Companion October2010

The essential publication for BSAVA members

PDPThe Professional Development Phase initiative P6

How ToDecide whether CT or MRI is best for your patient P14

The essential publication for BSAVA members

companionOCTOBER 2010

Respiratory problemsBrachycephalic dogsP22

Clinical Conundrum...a confusing case of polydipsia

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companion

3 Association NewsLatest news from BSAVA

45 Monty Halls Congress AdventureCongress 2011s keynote speaker

68 PDP Hit or Miss?Three years into the Professional Development Phase initiative, John Bonner reports on the scheme

913 Clinical ConundrumConsider a confusing case of polydipsia

1420 How ToDecide whether CT or MRI is best for your patient

21 Neurology to turn headsA look at BSAVAs forthcoming Neurology Roadshow

2224 PublicationsAirway problems in brachycephalic dogs

25 PetsaversLatest fundraising news

2628 WSAVA NewsThe World Small Animal Veterinary Association

2930 The companion InterviewSandy Trees

31 CPD DiaryWhats on in your area

Additional stock photography Dreamstime.com Joop Snijder; Nikolai Sorokin; Swinnerrr; Yuri Arcurs; Zoran Stojkovic

companion is published monthly by the British Small Animal Veterinary Association, Woodrow House, 1 Telford Way, Waterwells Business Park, Quedgeley, Gloucester GL2 2AB. This magazine is a member only benefit and is not available on subscription. We welcome all comments and ideas for future articles.

Tel: 01452 726700Email: [email protected]

Web: www.bsava.com

ISSN: 2041-2487

Editorial BoardEditor Mark Goodfellow MA VetMB CertVR DSAM DipECVIM-CA MRCVSSenior Vice-President Richard Dixon BVMS PhD CertVR MRCVS FRSE

CPD Editorial TeamIan Battersby BVSc DSAM DipECVIM-CA MRCVSEsther Barrett MA VetMB DVDI DipECVDI MRCVSSimon Tappin MA VetMB CertSAM DipECVIM-CA MRCVS

Features Editorial TeamCaroline Bower BVM&S MRCVSAndrew Fullerton BVSc (Hons) MRCVS

Design and ProductionBSAVA Headquarters, Woodrow House

No part of this publication may be reproduced in any form without written permission of the publisher. Views expressed within this publication do not necessarily represent those of the Editor or the British Small Animal Veterinary Association.

For future issues, unsolicited features, particularly Clinical Conundrums, are welcomed and guidelines for authors are available on request; while the publishers will take every care of material received no responsibility can be accepted for any loss or damage incurred.

BSAVA is committed to reducing the environmental impact of its publications wherever possible and companion is printed on paper made from sustainable resources and can be recycled. When you have finished with this edition please recycle it in your kerbside collection or local recycling point. Members can access the online archive of companion at www.bsava.com .

Spread the cost of membershipDirect Debit takes the hassle out of renewing your BSAVA membership. Did you know that as well as an annual renewal by Direct Debit, you can also choose to spread the cost of your subscription over twelve months?

Paying your annual membership by Direct Debit allows us to reduce your rate by 10 given that this is the most efficient and cost-effective way for BSAVA to administer your subscription. Already over 50% of paying members choose to pay this way. However, if you would find it more helpful to split your subscription, you can spread the cost throughout the year, with our 12 month payment plan. There is a 10 administration cost for this facility, yet paying monthly rather then in one lump sum might suit you better.

If Direct debit sounds attractive you have until 29 October to change your subscription payment method either an annual DD to save 10, or a monthly DD to spread the cost.

If you have any questions about your coming renewal or want to set up a DD email [email protected] or call 01452 726700 during office hours.

DETAILS UPDATEIn the coming months you will be renewing your membership and registering for Congress and this is the perfect opportunity to make sure all the details we have for you are correct. If you are reading your own copy of companion and it came to your house or workplace, then at least we know we have your address right! However, make sure your email address and all other details are correct too, as this is the best way to make sure we give you the best service and information possible.

You can also update your profile at any time online at www.bsava.com, or email [email protected] with your new details.

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ASSOCIATION NEWS

No other British veterinary conference offers as much choice for delegates, with over 40 streams over four days. The quality of the BSAVA Congress programme is acheived by a committee of volunteers vets and nurses working in all aspects of the profession who know whats needed to push the science forward and make your lives better and easier.

Weve introduced more interactive lectures, where you can vote and answer questions using keypads, management and communication streams, and an appropriate spread of cutting edge and controversial topics. So, new topics are head lined as well as the return of the ever popular subjects.

By using your exclusive free access to the lecture podcasts after the event, BSAVA Congress can enable you to complete your entire annual CPD, with some of the most impressive experts in the world. n

SuBmIT AN ABSTRACTSubmissions for Clinical Research Abstracts take place online until 28 October. Clinical research abstracts are a valued and integral part of Congress and run concurrently with the main scientific programme. BSAVA particularly welcomes submissions from practitioners, as well as from those in research and academia, but only online submissions can be considered. Visit www.bsava.com or call 01452 726705 for more details. n

31 march 3 April: the dates for BSAVA Congress 2011, and this month members will be sent priority registration packs, ahead of anyone else. Of course, members get the best discounts whenever and however they book. However, to really get ahead of the crowd and save money you can register online, as web registrations receive a 5% discount early and online is the very best way.

The price for veterinary nurses now includes the new advanced Nursing master Series, which means the event is brilliant value for money for everyone in the practice. Theres even a weekend rate now for the first time, offering even more registration options and making life easier. If you need any help with your registration or getting online then email [email protected] or call 01452 726700 during office hours. n

Book online now to save

Register for Congress online and save 5% on your registration

Each year on the Thursday of Congress, BSAVA holds its awards ceremony. The awards are made in recognition of the contributions made by individuals working in the field of small animal medicine and surgery and are just one of the ways BSAVA supports success in the profession. The Awards Committee, comprising the Presidents of the BSAVA, RCVS and BVA together with the chairs of the BSAVAs Scientific and Publications Committees, meet every December to consider nominations for Awards. Of course the Committee cannot make nominations and relies on the BSAVA membership putting forward names for consideration. Visit www.bsava.com to nominate a colleague or email [email protected] to get a nomination form. Nominations must be received before 12 November 2010. n

Nominate now for BSAVA awards

Not-to-miss science

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Congress

Monty Halls stunning stories of underwater experiences will be illustrated with amazing images and fantastic film footage from his adventures when he delivers the BSAVA Congress Lecture on the Thursday afternoon of Congress. He follows in the footsteps of the likes of Joe Simpson, Phil Hammond, Simon King and Susan Greenfield, who have all proved popular guest speakers with Congress delegates.

From marine to marine biologyHalls left the Royal Marines at the age of 29 after a successful career that included a stint in South Africa. He chose to study marine biology at the University of Plymouth, where he was involved with a project filming a rare species of crocodile in Belize in partnership with the Natural History Museum. He graduated with a First Class Honours degree in 1999.

Media careerHalls first caught the eye of television producers in 2004 when he won Channel 4s Superhuman show, and after that came two series of Great Ocean Adventures for Channel 5 and Journey To The Centre Of The Earth on Channel 4. His Great Hebridean Escape television series was shown in April/May 2010 on BBC2. This followed Montys experiences living in the Outer Hebrides for six months working as a volunteer wildlife ranger. Living in a restored crofters cottage on the island of North Uist, Monty and his dog Reuben (the real star of the show) explored the natural

Monty Halls Congress Adventure

Ocean adventurer, writer, television presenter Monty Halls next adventure will be to inspire BSAVA delegates with his tales of derring-do

Hes been variously described as the shark whisperer and the new Cousteau. Monty Halls is an adventurer in the true old-fashioned sense of the term. The former Royal Marines Officer is a professional diver and a trained marine biologist who has led teams through some of the most demanding environments in the world. His adventures include discovering prehistoric settlements amid great white sharks, avoiding the bullets of poachers, and photographing a dangerous rare crocodile underwater for the first time. A popular TV presenter, his two series of Monty Halls Great Escape for the BBC have won him fans worldwide.

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Congress

beauty of the area. A third series of Monty Halls Great Escape has been commissioned.

International adventuresMonty Halls first made the news in 2002 when he led a multinational team of adventurers and scientists to South-east India to discover the ruins of a lost civilization beneath the sea. This established Monty as a new star of British exploration. In South Africa, he led an international project seeking out sites of prehistoric settlements.

Before TV notoriety he had led a pioneering expedition in sea kayaks up the inland shore of one of Africas great rift lakes, photographing new underwater species and contacting remote villages and indigenous peoples en route. He has also led successful projects in Indonesia, Honduras and the Philippines. In total Halls has completed three circumnavigations of the earth, seeking out the greatest encounters in the oceans. He has also led an expedition to the ten greatest shipwrecks in diving, and memorable experiences include swimming with wild killer whales off New Zealand and exploring an ancient Maori cave system.

Awards and charitiesMonty has found time to record his adventures. He has published several books including Dive: The Ultimate Guide and Great Ocean Adventures, as well as a book about Beachcomber Cottage and his life-changing

CongressCongress

adventure living on the West Coast of Scotland for the first Great Escape series.

In 2003 Monty Halls was awarded the Bish Medal by the Scientific Exploration Society for his services to exploration. He is passionate about conservation, particularly of the worlds reefs and shark populations. He is a patron of several international charities including Help for Heroes, The Shark Trust, and The Whale and Dolphin Conservation Society, and is Honorary Ambassador to the Galapagos Conservation Trust.

His enthusiasm, energy, passion and sense of fun are said to be infectious. Halls style is dynamic, light-hearted, frequently hilarious, and hes open to investigation and questioning from the floor. His lecture will take place on the Thursday afternoon of Congress and all delegates can apply for a free ticket when they register.

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PDP

They said it was unnecessary and irrelevant and even if they wanted to do it, they couldnt because they would be unable to spare the time.Back in 2007 there were a significant minority of the graduating year who felt this way about PDP. They were being asked by their professional body to make a note of the numbers of different procedures they carried out in their first job in practice and to record the details on a password-protected website, along with their comments on how they felt their clinical skills were developing.

Being asked to carry out a potentially time-consuming task that was never demanded of previous generations of new graduates caused grumbling among many in that 2007 cohort. Yet the vast majority

did eventually register on the Royal College website 93 per cent of that years output, according to RCVS figures. It is believed that the remainder were mainly foreign students returning to their home countries or are working in non-clinical areas, such as meat hygiene work, where the PDP is irrelevant.

In theory, new graduates will be developing, what the College calls, Year 1 skills during the PDP process, but importantly it was never intended that the goal should be to complete this within a single year. Many young vets may not begin work immediately and they may decide to get their feet under the table in practice before signing up. Moreover, their progress in completing the PDP portfolio may depend on many factors including some beyond their control, such as the practice caseload, in addition to their own energy and commitment.

Improving trendsEncouragingly, the time taken to fill in and submit the required portfolio has shown a clear downward trend in the 2008 and 2009 cohorts, as successive waves of new graduates get a better understanding of both how the system operates and its possible benefits in providing them with more focussed and structured training in those first anxious months in practice.

Although it is too early for detailed comparisons between the different academic years, some trends are clear. On average, it took 16 months for the 2007 group to complete their PDP and 13.5 months for the next years cohort. The 2009 cohort are finding the process even easier, with 58 candidates having already completed and returned their portfolio before the end of August 2010.

Winning graduates overWill Oldham is a 2008 graduate from Edinburgh who completed his PDP while working in small animal practice with Cinque Port Veterinary Associates in Kent. He says that unhappiness with the schemes demands continued well beyond the first year. I was very sceptical about PDP at the beginning and there was quite a lot of animosity among my year group at being made to jump through yet another hoop. But I soon found it useful to be able to look back at my clinical records and see which areas I needed to

Three years into the Professional Development Phase initiative, the RCVS appears to be winning the battle to persuade new graduates of the need to record details of their postgraduate training. John Bonner asks some of those young veterinary surgeons how they feel about the scheme and wonders what changes may be planned for their future colleagues

PDP

PDPHit or miss?

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PDP

strengthen. I was getting a lot of cat neutering but not enough bitch spays. So I was able to go to my boss and ask for those cases to be passed on to me.

Working independently for the first time, it can be difficult for a newly qualified clinician to assess their own progress, said Aaron Harper, a 2008 Cambridge graduate at a practice in Burnley. The website is a very good tool for seeing how you are doing. You can compare the numbers of procedures that you have done with the average for your cohort. I perhaps lacked a bit of confidence in surgery at first and so it made me chase up cases that I might have avoided if I had been given the choice.

Less onerousOne reason for the increased acceptance of PDP is that recording the necessary data is not as tedious and time consuming as some may have feared. However, the new graduate must still be reasonably well organised, as 2009 RVC graduate Loreen Chan explains. I found it difficult to remember all the

cases I saw, so I wrote down everything I did in a notebook which I then added on to my PDP record later. It takes an average of an hour per week to record online but I think the time spent reflecting on cases to identify things that could be improved next time is well justified.

Ayrshire practitioner Fiona Brockbank, who graduated from Glasgow in 2008, found the website easy to navigate around and so the process was pain-free. The one thing I would warn others about is to remember to press save immediately after you have updated the numbers, otherwise you forget and move on to something else. I made that mistake a couple of times and it is very irritating.

However, not all the new graduates are entirely clear about their responsibilities for recording PDP data. Stephen Ware is one four senior clinicians appointed by the Royal College as postgraduate deans to monitor progress and give advice to the younger colleagues. One area of concern to the former Royal College president is that many of his charges record the numbers of procedures they undertake but add inadequate notes. We are not looking for a truncated version of the clinical notes, what we need is a few words to give us some assurance that the new graduate is thinking about what they have learned. In most cases these problems can be overcome by simply reading the explanatory notes and frequently asked questions on the website.

Another issue highlighted by fellow postgraduate dean Julian Wells is that of clinicians filling in the forms from the top downwards so that categories towards the bottom are completed in a rush, with unsatisfactory results. He notes that a high proportion of respondents fail to include anything in the section on biosecurity, with small animal practitioners maybe thinking that this only applies to farm animal work.

Of course, as Fiona Brockbank points out, it is impossible for the website text to fit every practitioners personal circumstances. So often the young vet has to interpret these instructions in a manner appropriate to their own situation. Biosecurity is not just a concept used in preventing epidemics in high-density pig herds it also necessary in preventing the transmission of infections between small animal patients.

it made me chase up cases that I might have

avoided

PDP

Aaron Harper

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PDP

PDP Hit or miss?

Finishing upAt the last count, 440 of the 662 registrants from the 2007 cohort and 295 out of 663 in the 2008 group have completed their PDPP requirements, so what has happened to the rest? To the frustration of the RCVS and postgraduate deans, their answer is We dont know. They have found that while it may be possible to persuade new graduates to sign up for PDP, it is a different matter getting them all to finish the job.

For the postgraduate deans, the problem is in maintaining contact with their charges. In their first few years in practice, new graduates are highly mobile and many dont bother to keep the Royal College informed of their new postal address. Even their email addresses may change, for example, in the case of RVC graduates who may use their college email for a limited period after graduation. Those PDP candidates that dont receive or even ignore the reminders sent out by the postgraduate deans, will find that this was a mistake when they do have to get in touch with their statutory body.

Aaron Harper was in contact with Horseferry Road when he decided to enrol for the new certificate in advanced general practice. He notes that his application would have been turned down if he hadnt already proved his competence in the more basic clinical skills through his completion of the PDP.

Yet not all young veterinary surgeons have the ambition to advance their professional expertise through the certificate system. How are the postgraduate deans to persuade the many stragglers to finish the course?

If the certification carrot doesnt work, the Royal College feels that it may be necessary to wave the stick of disciplinary proceedings. Although completing PDP is not a statutory requirement under the current legislation, there are potential consequences for those that ignore the RCVSs

advice. So the RCVS is planning to identify those that have not completed their PDP within two years of registration and have failed to respond to messages from their postgraduate dean. Defaulters will then be sent two further letters pointing out that CPD is a requirement for complying with the Royal College CPD policy and later that their non-compliance may be taken into account if a complaint about them is made to the colleges professional conduct department.

Making improvementsTo date, the RCVS has made no significant changes to the PDP system, believing that the initiative would need some time to become properly established. Any immediate changes would be confusing to both the new graduates and their employers, whose responsibilities are explained in a booklet sent out to each registrant.

However, now would be a good point to look for possible improvements, says Freda Andrews, head of the RCVS education department. Three years is a very long time in world of IT and her colleagues are talking with a software designer on plans to update the website. This process will take into account the comments received from those sending in their PDP portfolio. Loreen Chan recalls her confusion when she started the PDP process with the requirements for entries in the notes section of the log. My postgraduate dean, Professor Agnes Winter, provided me with a few examples of reflective notes from another graduates PDP. This was exceptionally helpful and I think some examples of notes should be included in the guidelines for the future.

Any modifications to the PDP system will not be considered in isolation. Ms Andrews explained that the Royal College is currently discussing with the seven UK schools a plan for a similar system for online recording of the training received by veterinary undergraduates in their extramural studies. Rather than allowing each school to go it alone, the RCVS will take the lead in trying to encourage institutions with different training cultures to use the same software system.

She hopes that by introducing a self assessment system for recording a young clinicians developing skills and competencies at student level, this will have benefits as they progress to the PDP and beyond. Many other equivalent professions already have an online system for keeping these records. If members can become familiar with what is expected of them when they are undergraduates we hope it will become a seamless process as they continue into PDP and then into a career of lifelong learning. n

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CLINICAL CONUNDRUM

Clinical conundrumconundrum

Mary Trehy, intern at Davies Veterinary Specialists invites companion readers to consider a confusing case of polydipsia

Case presentationA 12-year-old, 30 kg male entire Golden Retriever presented with a 2 day history of weakness and anorexia. The owner describes a weak and wobbly hindlimb gait and reports that the dog is drinking excessively. She has estimated his water intake is approximately 4 litres daily. On presentation, the dog is subdued, rectal temperature is 38.1C and heart rate is 68 bpm. Peripheral pulse quality is good and mucous membranes are moist and pink. Thoracic auscultation and abdominal palpation are unremarkable.

Create a problem list based on the information so farThe problem list consists of:

Anorexia Polydipsia (as estimated water intake

(4000 ml/30 kg) exceeds 100 ml/kg/day) Hind limb weakness Ataxia.

As a clinical sign, anorexia has low diagnostic value and is commonly a sequel to a primary disease process; therefore, it is appropriate to direct investigations towards the main problems of polydipsia, ataxia and weakness.

potassium and calcium), hypoglycaemia, anaemia or endocrinopathies. Given the ataxia, a neurological condition was considered more likely. Differentials to consider for primary neuromuscular weakness include peripheral neuropathies, junctionopathies and myopathies.

Construct an initial diagnostic plan. What is your rationale for performing these tests?Initial investigations should include a haematology profile, to assess for alterations in leukogram and to rule out anaemia (although the clinical examination was not suggestive of marked anaemia). A full biochemistry screen, in conjunction with urinalysis, is indicated to evaluate serum electrolytes (particularly sodium, calcium and potassium) and to investigate other potential causes of polydipsia (for example renal or hepatic disease). A full neurological examination is required to further investigate the weakness.

The results of these initial investigations are presented in Table 1 parts ad.

Haematology Reference Interval

RBC 5.12 x 1012/L (5.08.5)Hb 12.5 g/dL (1218)

Hct 39 % (3755)

Platelets 160 x 109/L (160500)

WBCs 12.5 x 109/L (615)Neutrophils 11.25 x

109/L(3.011.5)

Lymphocytes 1.13 x 109/L (1.04.8) Monocytes 1.13 x 109/L (0.01.3)Eosinophils 0.0 x 109/L (0.01.2)Basophils 0.0 x 109/L (0.00.2)Platelet comment: Occasional small cluster

Table 1a: Haematology

What are your differentials for these problems?Differentials for polydipsia in this case include structural renal disease, diabetes mellitus, hyperadrenocorticism, pyelonephritis and electrolyte derangements (hypercalcaemia or hypokalaemia). Other differentials including diabetes insipidus and renal glucosuria are less common and were considered less likely.

The dogs hindlimb weakness could be a consequence of primary neuromuscular disease or could be seen in association with metabolic disorders including electrolyte imbalance (particularly

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CLINICAL CONUNDRUM

Clinical conundrum

Biochemistry Reference Interval

Total protein 75 g/L (5277)Albumin 39 g/L (2640)

Globulin 36 g/L (2047)Sodium 140 mmol/L (139154)Potassium 3.3 mmol/L (3.56.0)Chloride 105 mmol/L (99125)Magnesium 1.0 mmol/L (0.61.2)Total calcium >4.0

mmol/L(23)

Ionised calcium

1.98 mmol/L

(0.752.0)

Phosphate 0.64 mmol/L (01)Urea 11.1

mmol/L(29)

Creatinine 138 mol/L (40106)ALT 25 U/L (025)

Alkaline phosphatase

148 U/L (20150)

Total bilirubin

5 mol/L (09)

Glucose 5.4 mmol/L (3.55.5)Cholesterol 5.1 mmol/L (3.87.0)Amylase 478 U/L 01800)Lipase 200 U/L (0250)

Table 1b: Biochemistry

UrinalysisSample appearance Pale yellow, clear Specific gravity 1.009pH 5Protein Negative

Glucose NegativeKetones Negative

Urobilinogen NegativeBilirubin Negative

Haemoglobin NegativeRBCs 1 /hpfWBCs 3 /hpfCrystals None seen Casts None seen

Table 1c: Urinalysis

Neurological exam Left RightMental status Normal

Fundus Normal

Cranial nervesI Olfaction 2 2

II Menace 2 2

Following 2 2

Obstacle course 2 2

III PLR 2 2

Consensual PLR 2 2

Strabismus Absent Absent

IV Lateral rotation Absent Absent

V Motor 2 2

Sensory 2 2

VI Medial strabismus Absent Absent

VII Facial muscles 2 2

VIII Hearing 2 2

Head tilt Absent Absent

Nystagmus spontaneous Absent Absent

Nystagmus positional Absent Absent

Nystagmus physiological Present Present

IX/X Swallowing, gag NormalXI Trapezius Not performed

XII Tongue muscles 2 2

Postural reactions

Wheelbarrowing 1 1

Extensor thrust 1 1

Hemistand 1 1

Hemi-walk 1 1

Proprioception 1 1

Hopping 1 1

Tactile placing Not performed

Visual placing Not performed

Spinal reflexesBiceps Not performed

Patellar 1 1

Anal 2 2

Panniculus 2 2

Withdrawal reflexes

Thoracic limb 1 1

Pelvic limb 1 1

Nociception

Thoracic limb 2 2

Pelvic limb 2 2

Head 2 2

Perineum 2 2

Table 1d: Neurological exam. 0 absent, 1 reduced, 2 normal, 3 exaggerated


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CLINICAL CONUNDRUM

How does your interpretation of the test results help you refine your problem list and differential diagnoses?Haematology was unremarkable. The main significant findings on biochemistry were a high total and ionised calcium, mild azotaemia and mild hypokalaemia. Other electrolytes were within normal limits. The urine sampled was isosthenuric but otherwise normal.

Diabetes mellitus can be excluded on the basis of biochemistry and urinalysis. Hyperadrenocorticism is considered unlikely given the absence of a stress leukogram. The urine specific gravity is inappropriately low and given the azotaemia could suggest renal dysfunction. This interpretation is complicated by the presence of hypercalcaemia, as this impairs the function of ADH and results in the production of dilute urine. The presence of hypercalcemia would explain both polydipsia and the anorexia. The history of anorexia could account for the hypokalaemia.

The neurological exam revealed reduced hind limb spinal reflexes with reduced postural reactions and withdrawals in all four limbs. These findings are consistent with a peripheral neuropathy, junctionopathy or myopathy. There is no direct evidence for a metabolic cause of the dogs weakness although hypercalcaemia can exacerbate pre-existing neuromuscular weakness.

The revised problem list therefore includes:

Anorexia Weakness Ataxia Polydipsia Hypercalcaemia Neuromuscular disease

What are your differential diagnoses for hypercalcaemia and can these be narrowed based on the information so far?

addressed as a priority.In this case, intravenous fluid therapy

with 0.9% NaCl at 6ml/kg/hr was initiated. After 24 hours of fluid therapy, ionised calcium remained significantly elevated, so following adequate rehydration, furosemide was prescribed (at 2 mg/kg BID) to promote calciuresis and IVFT was continued at 2 ml/kg/hr.

In order to investigate the cause of the hypercalcaemia a rectal exam, thoracic radiographs and abdominal and cervical ultrasound were indicated (to assess for evidence of neoplasia and evaluate the parathyroid glands). Further investigation for neuromuscular disease was also indicated, to distinguish between a junctionopathy (e.g. Myaesthenia gravis), a peripheral neuropathy or a myopathy.

Following furosemide, serum calcium normalised. Thoracic radiographs were performed under general anaesthesia and were unremarkable. Electromyography (EMG) was also unremarkable. Repetitive nerve stimulation was not suggestive of myasthenia gravis (which would typically produce a decremental amplitude during the stimulation train), however nerve conduction studies indicated reduced conduction velocity (31 m/s) of the sciatic nerve (: reference range 6080 m/s) with polyphasia and temporal dispersion (Figure 2).

These findings were suggestive of a polyneuropathy. However, EMG changes would also be expected with a polyneuropathy as the loss of some axons causes the muscles they innervate to become hyperexcitable. This is usually evident as fibrillation potentials or positive sharp waves. The normal EMG in this case may be due to the acute onset of neuromuscular signs as these changes take 57 days to develop.

A nerve biopsy was considered to further characterise the disease but as this

The differentials for hypercalcaemia are most easily remembered with the mneumonic HARD IONS G

Hyperparathyroidism Addisons (and hypervitaminosis A) Renal secondary

hyperparathyroidism Vitamin D toxicity Idiopathic (Cats) or Iatrogenic (oral

phosphate binders) Osteolysis Neoplasia Spurious result (lipaemia,

postprandial) Granulomatous Dx

The most commonly diagnosed cause of hypercalcaemia is humoral hypercalcaemia of malignancy, seen particularly with lymphoma and anal sac adenocarcinoma. Other differentials to consider in this case are primary hyperparathyroidism and granulomatous disease.

Hypervitaminosis D and lytic bone lesions were unlikely differentials owing to a lack of known toxin exposure or hyperphosphataemia on biochemistry. Renal secondary hyperparathyroidism was also considered unlikely as ionised calcium tends to be decreased or low-normal in these cases.

What are the immediate treatment priorities and what further investigations would you perform?With the potential adverse effects of sustained hypercalcaemia (mineralisation of soft tissues and potential renal failure due to nephrocalcinosis), this should be


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CLINICAL CONUNDRUM

was unlikely to alter the management of the patients condition, it was not performed.

Cervical ultrasound revealed a discrete, 0.3 cm by 0.6 cm, hypoechoic nodule at the caudal pole of the left parathyroid gland (parathyroid diameter of greater than 0.2 cm is considered abnormal). A diffuse but non-specific mild increase in hepatic echogenicity was identified on abdominal ultrasound when comparing the hepatic parenchyma with the relative echogenicity of the neighbouring spleen and falciform fat. No parenchymal nodular pattern or ultrasonographic pattern of hepatic vascular congestion was identified. All other structures were considered unremarkable.

How do these findings influence your differential diagnoses and which further tests are indicated?Following the ultrasonographic demonstration of a parathyroid nodule, primary hyperparathyroidism was considered the most likely differential for hypercalcaemia, The other abdominal

Clinical conundrum

Endocrinology Reference Interval

Parathyroid hormone

2.2 pg/ml (0.025.0)

Table 2: PTH assay result

changes were considered less likely to be significant at this time. As the parathyroid nodule represented a potential source of autogenous PTH production, a PTH assay was conducted. EDTA plasma samples were collected for PTH assay and were transported immediately. The laboratory was contacted to ensure samples had been frozen upon receipt pending analysis. Results, shown in Table 2 were available within 48 hours.

Golden Retrievers was possible and may have been exaggerated by the presence of hypercalcaemia.

What is your interpretation of the PTH results?The PTH value is at the low end of the reference interval, which is appropriate for a hypercalcaemic state. This result suggests the parathyroid mass was not autonomously producing PTH and is thus not responsible for the patients hypercalcaemia. The mass could originate from the thyroid or a parathyroid gland but given the PTH result it was felt unlikely to be related to the clinical picture. So it was elected to re-evaluate the patient and problem list before further action.

Based on the information so far what are your most likely differentials and what are your next steps?Low PTH with elevated ionised calcium and normal phosphorus is compatible with humoral hypercalcaemia of malignancy. In this condition production of

Figure 1: Motor nerve conduction study of the right sciatic nerve revealing reduced conduction velocity

Figure 2: Cervical ultrasound revealing a parathyroid nodule (small arrows) within the thyroid (large arrows)

Differentials for polyneuropathy at this stage included a paraneoplastic syndrome. Although infrequent, this has been reported in dogs with bronchogenic or mammary carcinoma, lymphoma and multiple myeloma. Idiopathic and hypothyroid polyneuropathy were also considered possible. Congenital polyneuropathies were excluded on the basis of age however a degenerative neuropathy described in


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CLINICAL CONUNDRUM

WRITING A CLINICAL CONUNDRUM IS AS HELPFUL AS READING ONEI observed this case being worked up during a medicine rotation as part of my internship. I found the case interesting but slightly confusing, so spent some time discussing the diagnostic approach and the interpretation of test results with the clinician in charge.

I felt it would be useful to write the case up and decided to submit it to companion. I saw it as an opportunity to understand the case more fully and to gain some experience of writing an article for peer-review. I was given advice on submitting Clinical Conundrums and also some more general guidance on the problem oriented approach to medicine cases, which I found really helpful.

Having had a first attempt at the article, I was given some pointers on areas to expand upon and revise. In particular, emphasising how each test result allowed us to refine the differential diagnosis list. After more reading of lecture notes and textbooks and some further revisions, I submitted the article for review. The constructive feedback from the editor was also really useful and comparing my first and final drafts, I can see how much my understanding of the case has improved.

I would definitely recommend submitting a case to other interns; its a great opportunity to feel more involved with a case and to learn to justify every step taken in reaching a diagnosis.

Mary Trehy

other mediators (including Parathyroid hormone related peptide (PTHrP) and Osteoclast Activating Factor (OAF)) accounts for calcium release. Options for further investigations include measurement of PTHrP and repeating screening imaging. Given the delay in processing a PTHrP assay, it was elected to repeat imaging before submitting a sample for determination of PTHrP.

Abdominal ultrasound was repeated first to re-evaluate the mild changes previously identified in the liver as 4 days had elapsed. This revealed increased echogenicity of the liver and an irregular increased echogenicity in the spleen. Fine needle aspirates (FNAs) were taken from the liver and spleen to further characterize the nature of this non-specific pattern and were submitted for cytological analysis.

An experienced pathologist should evaluate the smears in detail but what are your initial impressions of the cytology pictures?

What is the final diagnosis and can you explain all of the problems you have identified? What treatment options are available?A diagnosis of hepatosplenic lymphoma with paraneoplastic polyneuropathy and humoral hypercalcaemia of malignancy is sufficient to explain all of the clinical signs and test results encountered.

This dogs lymphoma would be classified as at least WHO stage IV (indicating involvement of the liver and/or spleen) and sub-stage b (due to the presence of clinical signs). Based on the certainty of the diagnosis achieved with clinical and cytological findings, histological confirmation of the diagnosis was not deemed necessary. Similarly, immuno phenotyping the lymphoma would not have affected treatment decisions in this case.

Treatment options include palliative

Figure 3:FNA of the hepatic parenchyma

The splenic and hepatic samples consist of a population of large mononuclear cells with variable to very high nuclear: cytoplasmic ratio, moderate mitotic rate and moderate nucleoli. Such cells are neoplastic round cells. These changes were considered by the clinical pathologist to be consistent with hepatosplenic lymphoma.

prednisolone or chemotherapy. The majority of chemotherapy protocols are based on either COP (cyclophosphamide, vincristine and prednisolone) or CHOP (also including doxorubicin) protocols. Additional agents (for example L-asparaginase and lomustine) can be employed as rescue therapies.

The mean survival times for canine lymphoma treated with a COP or CHOP protocol are reported as a 68 months and 13 months, respectively. However the presence of clinical signs, paraneoplastic polyneuropathy and hypercalcaemia are all poor prognostic indicators. In this case; the owners elected to treat with a CHOP protocol.

Over the following 4 weeks the dog remained normocalcaemic and its strength improved. Unfortunately the dog then relapsed, exhibiting weakness and anorexia and at this point the owners elected for euthanasia.


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Figure 1: (A) External appearance of a CT scanner. (B) External appearance of a high field MRI scanner (image courtesy of the Animal Health Trust). (C) External appearance of a low field MRI scanner

A

B

C

How to

Decide whether CT or MRI is best for your patient

Victoria Johnson of Vet CT Specialists Ltd helps us make this decision

There has been a rapid increase in the availability of cross-sectional imaging techniques in recent years. CT and MRI are now readily accessible in many referral institutions. In addition, mobile MRI and CT units make frequent visits to veterinary practices all over the UK and some first opinion practices are investing in low field MRI systems and CT scanners. This means that vets are now faced with a situation where they have the choice between these two advanced imaging modalities and a need to understand their respective strengths and weaknesses.

This article aims to simplify that choice and guide you in selection of an appropriate imaging modality. In some situations this is easy and there is a clear clinical benefit to using one modality over the other. There are, however, some circumstances where other factors such as cost, time, accessibility or personal preference become more important in selection.

What is CT?Computed tomography (CT) (Figure 1A) is a cross-sectional imaging modality based on X-ray technology. X-rays are produced from a high-powered X-ray tube and pass through the patient to be received by a panel of detectors. The X-ray beam is attenuated as it passes through the patient and this allows an image to be created based on the relative density of the different

body parts. In most modern X-ray machines the tube rotates around the patient as the CT bed moves forwards or backwards. The bed can either move in small steps, creating a single slice of the patient, or can move constantly as the tube rotates. The latter creates a helix of imaging data from the patient (so-called helical CT) that can then be reconstructed by a computer into different formats.

Usually the data are reconstructed into transverse slices of varying thickness, but sagittal, dorsal and three-dimensional reconstructions can also be created and are extremely useful. The most up-to-date CT scanners have multiple panels of detectors to receive the X-ray beam after it has passed through the patient. This multidetector CT (MDCT) technology allows extremely rapid imaging (as little as 10 seconds to image an entire dog from nose to tail) and generates a volume of attenuation information, thus enabling exquisite multiplanar and 3D reconstructions. MDCT also facilitates highly detailed CT angiography to be performed using iodinated contrast media.

CT Key features Ionising radiation Equipment, setup and maintenance

usually cost less than MRI Images acquired in transverse

plane, but with MDCT additional planes can be reconstructed with equivalent resolution

Extremely quick, especially MDCT Intravenous iodinated contrast

media used for most examinations* Can easily perform angiography

with helical CT scanners

* In general contrast medium is advised for most CT examinations with the exception of cases where its administration could compromise the health of the patient, or in cases where bone imaging alone is required.

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What is MRI?Magnetic resonance imaging (MRI) is based on the use of strong magnetic fields and radiofrequency pulses to generate cross-sectional images. The patient is placed into a large magnet and the powerful magnetic field results in the alignment of hydrogen atoms within the body. Different radiofrequency pulses and additional gradient magnetic fields are then turned on and off to create a complex set of frequency information that can be transformed into an image. Unlike CT, images of the patient can be acquired in any plane (sagittal, dorsal, transverse, or oblique).

Magnetism is measured by means of a unit, the Tesla (T). Two main types of MR scanner are available: low field and high field (Figures 1B and 1C). The low field magnets have a smaller magnetic field (0.20.5 T usually) and are open devices. These are considerably cheaper than high field magnets and have a smaller field of view. The image quality especially of the brain and head is usually good, though sequences generally take longer to acquire than with high field magnets.

High field magnets are supercooled with liquid helium. They are larger, more expensive structures with a closed gantry. The images are quicker to acquire and of high quality due to the higher signal-to-noise

part. This usually facilitates the choice of CT or MRI, as there are some clearly defined differences between the modalities when considering specific anatomical regions.

1. Central nervous system (CNS)MRI is the imaging modality of choice for the central nervous system due to its superior contrast resolution. There are many subtle changes that are seen on MRI of the brain and spinal cord that simply cannot be detected on CT. Also, CT has limitations in evaluation of the brain and spinal cord due to artefacts created by the surrounding bone of the skull and vertebrae. These artefacts create more of a problem in canine and feline patients (due to their smaller brain size and thicker skull and overlying musculature), than they do in human patients.

Specific MRI sequences can also be used in the CNS and present additional

Figure 2: Transverse MR scan through the caudal fossa of a 13-year-old dog. This is a particular sequence called a gradient echo (or T2*) scan, which aids in the detection of haemorrhage. The multiple lesions present are haemangiosarcoma metastases

MRI Key features No ionizing radiation Relies on magnetic fields and radiofrequency pulses to generate an image Creates a map of hydrogen atoms within the body Equipment, setup and maintenance usually more expensive than CT Two main types of scanner: low and high field strength Can acquire images in any plane Usually takes longer than CT Much greater contrast between the soft tissues than in CT Intravenous contrast medium (gadolinium) used in many examinations Numerous advanced techniques can be performed (generally with a high field

scanner)

ratio compared to low field systems. High field MR scanners are much more suited to angiography and other advanced imaging techniques than the low field scanners.

In MR imaging different combinations of radiofrequency pulses and gradient magnetic fields are used to create sequences of images with different contrast. Many different MRI sequences are available. By utilising different sequences and techniques and also by the administration of intravenous contrast medium (gadolinium) it is possible to be very precise about the nature of a lesion. For example, haemorrhage (Figure 2), fat, proteinaceous fluid and pure water are amongst substances that have very specific imaging characteristics on MRI.

More advanced imaging techniques are also available. These include: diffusion weighted imaging (used in ischaemic strokes); diffusion tensor imaging (used in fibre mapping and demyelinating disease); and functional MRI (identifies areas of neural activity by evaluation of blood oxygen levels).

Selecting an imaging modality depending on the anatomical regionOften a patient is sent for cross-sectional imaging for evaluation of a particular body

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advantages over CT. These include: gradient echo sequences for the diagnosis of haemorrhage (Figure 2); diffusion weighted imaging in the evaluation of ischaemic disease; FLAIR sequences to assist in diagnosis of perilesional oedema and identification of pure fluid; and STIR sequences to evaluate muscle, bone and nerve root changes.

The use of CT alone to diagnose spinal cord disease in the acutely paretic or plegic patient is controversial. Extruded mineralised disc material in chondrodystrophoid patients is easily visualized in non-contrast CT scans, but CT myelography is necessary to identify significant sites of spinal cord compression or expansion. CT myelography does not, however, allow detailed assessment of the parenchyma of the spinal cord. The presence of related, or unrelated, intramedullary lesions is better recognized

on MRI without the inherent risks of myelography (Figure 3).

The use of CT alone to diagnose brain disease should be limited to situations where MRI is not available. CT can be used to identify an intracranial mass effect, areas of severe oedema or acute

Figure 4: Transverse CT scan of the brain after intravenous contrast medium. A ring enhancing mass is present in the right parietal lobe. CT can demonstrate large contrast-enhancing mass lesions within the brain, but subtle parenchymal lesions will be missed. Note the lack of detail seen within the remainder of the brain parenchyma on a typical brain CT scan

Figure 3: (A) Sagittal T2W MR scan through the cervical spine of a 3-year-old Rottweiler. The patient has a subarachnoid cyst (red arrow). MRI not only demonstrates the presence of the cyst, but also shows the associated parenchymal hyperintensity within the spinal cord at C3 (blue arrow). (B) Sagittal reconstruction from a MDCT scanner of the thoracic and lumbar spine after lumbar myelography. This patient is a 3-year-old French Bulldog and also has a subarachnoid cyst. CT myelography demonstrates the presence and location of the cyst (yellow arrow), but it is not possible to evaluate the spinal cord parenchyma. This patient also has multiple vertebral abnormalities and a kyphosis. Osseous vertebral changes are clearly demonstrated by CTB

A

CNS Key features MRI preferable in almost every situation for brain and spine imaging MRI offers many significant advantages in terms of tissue contrast and special

sequences to identify particular pathology CT can be used if MRI is not available:

To identify a mass effect, severe oedema, acute haemorrhage or contrast-enhancing lesions in the brain or spinal cord

With myelography for the assessment of extradural compressive lesions in acutely presenting paretic or plegic patients

CT is often useful in addition to MRI in: Trauma Skull and vertebral malformations Degenerative lumbosacral stenosis

haemorrhage and contrast-enhancing brain (Figure 4) or meningeal lesions. Brain CT may overlook many subtle, but significant brain lesions that would be easily detected on MRI. Note that CT is not generally suitable for assessment of foramen magnum herniation.


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There are many instances where CT is complementary to MRI in evaluation of the CNS these include skull and vertebral malformations (Figure 3B), trauma cases and lumbosacral stenosis. In some trauma situations CT can be suitable for first line imaging of the CNS to assess for fractures and overt oedema/haemorrhage. This can even be performed in non-anaesthetised comatose patients due to the rapid image acquisition of CT.

2. Nasal cavities and sinusesBoth CT and MRI are extremely useful in assessment of the nasal cavities and frontal sinuses. CT and MRI are effective in the assessment of turbinate, maxillary and palatine destruction (Figure 5), mass lesions, presence of fluid, osteomyelitis, and contrast-enhancing lesions. Whilst CT and MRI are both able to detect cribriform

plate destruction, rostral meningeal/brain enhancement or mass lesion, MRI has the advantage that it may also demonstrate T2W meningeal hyperintensity surrounding the olfactory lobes in cases of nasal neoplasia. The cause of this finding is, as yet, unknown but it may represent micrometastases, secondary meningitis or an accumulation of fluid. It has not been shown to have an effect on neurological deficits or survival time.

CT can be used to guide fine needle aspiration (FNA) and biopsy if required. CT of the thorax can easily be performed at the same time as nasal CT in order to evaluate for metastatic disease.

3. External, middle and inner earsCT and MRI are both able to detect the presence of fluid or mass lesions within the tympanic bulla and external ear canal, sclerosis or erosion of the bulla wall, associated retropharyngeal or para-aural lesions and regional lymphadenopathy

Nasal cavities and sinuses Key features Both CT and MRI are very useful Both can demonstrate cribriform

plate invasion and rostral brain involvement in nasal neoplasia

MRI may show additional meningeal changes surrounding the olfactory bulbs in nasal neoplasia

CT can be used to guide FNA or biopsy

CT can be used for thoracic metastatic screening

Figure 5: Transverse CT scan through the nose of a 6-year-old dog with aspergillosis. CT provides exquisite detail of the nasal chambers and demonstrates severe left-sided turbinate destruction

AFigure 6: (A) Transverse CT scan (bone algorithm) at the level of the tympanic bullae in a 7-year-old Weimaraner with chronic otitis media. The right tympanic bulla wall is thickened and irregular, and both bullae contain abnormal material. (B) Transverse T1W/C transverse MR scan through the tympanic bullae of a cat with severe chronic ear disease and clinical signs of otitis interna. In addition to the abnormal material within the bullae, MR also demonstrates contrast enhancement of the right vestibulocochlear nerve (purple arrow) and suspected meningeal enhancement around the brainstem (yellow arrow)

B

(Figure 6A). MRI has an additional advantage in enabling evaluation of the facial and vestibulocochlear nerves for thickening and enhancement (Figure 6B) and also allows visualization of the fluid signal within the cochlea and semicircular canals. Associated brain disease is also best assessed by MRI, but may be recognized on CT.

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CT can be used for thoracic metastatic screening if aural/para-aural neoplasia is suspected.

External, middle and inner ears Key features CT or MRI can be used MRI can also assess cranial nerves

VII and VIII, the cochlea and semicircular canals and the adjacent brainstem

CT can be used for thoracic metastatic screening

4. ThoraxThe inherent variation in densities within the thorax makes the chest ideally suited to CT evaluation (Figures 7 and 8). Conversely, the low signal from the air-filled lungs and the presence of artefacts means that MRI is far less suited to assessment of the thorax. Overall, CT is the preferred modality for assessment of the thorax, though MRI can be useful in the assessment of the thoracic wall, mediastinal masses, the pleural space

Figure 8: Dorsal MDCT reconstruction of the thorax (at the level of the tracheal bifurcation) in a young dog. The right caudal mainstem bronchus is dilated and contains an abnormal structure. This was found to be a Holly leaf at bronchoscopy and surgery was required for removal

Figure 7: Transverse CT scan (lung algorithm) through the mid thorax of an 11-year-old mix breed dog. A large left-sided lung mass is present. Thoracic CT provides excellent pulmonary detail and also enables assessment of regional lymph nodes and a search for pulmonary metastases. Post-contrast images were also acquired (soft tissue algorithm)

Figure 9: Dorsal T2W MR scan of the ventral part of the thorax of a 3-year-old dog with chronic pyothorax. The scans were obtained prior to surgery (CT was not available) to locate loculated fluid and to assess for possible foreign material. The areas of high signal represent fluid pockets. The low signal structure is the apex of the heart

Thorax Key features CT is definitely the modality of choice

Extremely useful in the evaluation of pleural, mediastinal, bronchial, pulmonary parenchymal and thoracic wall lesions

Superior metastatic screening when compared to radiographs MRI can be used for thoracic imaging in some situations

Useful for mediastinal masses, thoracic wall masses and the pleural space Respiratory and cardiac gating techniques are usually required Cardiac MRI can be performed with extremely advanced MR scanners

(Figure 9) and, with a suitable scanner and compatible equipment, the heart. Images using either modality should be obtained during periods of apnoea. With rapid CT machines this can usually be achieved by hyperventilating to an apnoeic state or by the use of remote ventilation and breath-hold techniques. Respiratory and cardiac gating techniques are usually required for MRI of the thorax.

5. AbdomenCT provides excellent images of the abdominal organs and peritoneum (Figure 10). Contrast should always be administered (see CT Key features, page 14) and with helical CT (particularly MDCT) it is also possible to obtain exquisite angiographic studies. Contrast CT is extremely useful for CT excretory urograms, portosystemic


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potential for cartilage imaging, but powerful scanners are required for this level of detail.

Shoulder Key features MRI has great potential for the

assessment of muscular, tendinous and ligamentous shoulder injury

CT is much less useful overall and is reserved for osseous disease

Elbow Key features CT usually recommended Quick and provides excellent

osseous detail Ideal for the diagnosis of common

elbow conditions (medial compartment disease, IOHC, OC, elbow incongruity)

Complementary to arthroscopy MRI may also be used and could

provide additional information concerning bone oedema and cartilage

Abdomen Key features CT is the current modality of choice,

providing good quality images and being much easier to perform

MRI can be used but requires special sequences and expertise

In the future MRI may be used more for the characterization of abdominal masses and nodules in veterinary patients

Pelvic region Key features Either CT or MRI may be used MRI may hold a slight advantage

with its benefits of additional soft tissue contrast

6. Pelvic regionBoth CT and MRI are suited to evaluation of the pelvic region. This area is not prone to movement artefact, and therefore MRI may hold the advantage over CT given its superior soft tissue contrast and the ability to assess the adjacent CNS structures more readily.

8. ShoulderMRI offers significant potential for the evaluation of muscular, ligamentous and tendinous shoulder injuries in adult dogs. Some of these conditions are not seen arthroscopically and hence may be underdiagnosed. MRI is also well suited to the diagnosis of brachial plexus disease.

CT of the shoulders is generally much less useful. Osteochrondrosis lesions in young patients are usually seen radiographically and assessed and treated arthroscopically. CT may be helpful in fracture assessment and can also be used for assessment of suspected neoplasia with the addition of a thoracic metastatic scan.

Expertise and experience are essential to obtain the most relevant information from abdominal MRI.

7. ElbowCT has been the most widely reported cross-sectional imaging technique in the assessment of canine elbow disease. CT is ideally suited to the osseous changes of medial compartment disease, osteochondrosis (OC) lesions and incomplete ossification of the humeral condyle (IOHC). CT and arthroscopy have been shown to be complementary techniques, with CT identifying some lesions not seen on arthroscopy and vice versa. CT has also been used quantitatively in the assessment of elbow incongruity.

More recently MRI has been advocated in the detection of subtle intramedullary abnormalities such as bone oedema. MRI also theoretically holds the

shunt diagnosis, presurgical assessment of abdominal masses, and many other indications. It may even be preferable to abdominal ultrasonography in large obese patients.

MRI of the abdomen allows excellent evaluation of the parenchyma of the organs due to the good soft tissue contrast. Body MRI is used widely in people for the assessment of hepatic, splenic and renal nodules and masses and also for prostatic disease. Once again, rapid sequences and/or gating are usually required.

9. General skeletonCT offers the advantage of superior multiplanar and volume rendered 3D reconstructions which are extremely beneficial in the planning of fracture repair

Figure 10: Dorsal MDCT reconstruction of the abdomen after intravenous contrast medium administration. This 11-year-old dog has a large heterogenous right-sided liver mass (black arrow), which can be seen displacing the portal vein (white arrow) to the left. CT was used to perform a full assessment of the mass, regional lymph nodes, other abdominal organs and the thorax

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ConclusionVeterinary practices now have unprecedented access to cross-sectional imaging modalities. In many situations CT and MRI can be used interchangeably and the decision on which to choose may be mostly affected by cost and availability. There are, however, some important situations where the correct choice is extremely important and the wrong modality may make the study non-diagnostic for the disease process in question.

for the same purpose. The CT studies are quick to acquire if MDCT is used, whereas special protocols are required for fast MRI screening techniques. All of these types of studies take a long time to read, but certainly are useful in detecting previously unrecognized metastatic disease. In these whole body techniques the emphasis is generally on contrast rather than spatial resolution and MRI holds the advantage in the detection of bone marrow changes, lympadenopathy, soft tissue lesions and CNS lesions. CT remains beneficial in metastatic lung and bone imaging, but the latter is probably better assessed using bone scintigraphy.

In the future, positron emission tomography (PET) may become increasingly important in cancer staging. PET/CT or PET/MRI may eventually become the gold standard of cancer imaging in our canine and feline patients.

Patients with metallic implants CT or MRI?Metallic implants create problems for both CT and MR examinations.

In MRI non-ferrous implants may be placed into the magnet, but can create serious artefacts and hence non-diagnostic studies. The magnitude of these artefacts differs depending on the MR sequence used.

The artefacts identified on CT examinations in patients with metallic implants can also prevent interpretation, but on occasion the gantry can be angled to avoid the metallic region and certain slices and reconstructions can limit their effect on the final image.

CT and MR angiographyBoth CT and MR have a role in angiography in our small animal patients. Current applications include evaluation of portosystemic shunts, assessment for

General skeleton Key features CT useful for angular limb

deformities, fracture repair planning MRI advantageous in neoplastic

disease (such as mandibular or maxillary tumours)

pulmonary thromboembolic disesase, planning of vascular mass resection and many others. For CT angiography a helical scanner is required and a rapid injection pump is preferable (Figure 12). For MR angiography the best results are achieved with high field scanners and special techniques such as parallel imaging.

and other orthopaedic surgeries such as angular limb deformity correction (Figure 11). MRI is more advantageous where neoplastic invasion into bone is suspected. In this scenario the altered intramedullary bone signal may be seen long before lytic changes are recognized on a CT examination.

Whole body MRI and CT for metastatic disease?Recently protocols for whole body MRI screening for the diagnosis and staging of neoplastic disease have been reported. Some institutions are also routinely performing whole body CT examinations

Figure 11: 3D CT reconstructions can be useful to assess the overall alignment of osseous elements of the axial and appendicular skeleton for surgical planning

Figure 12: CT angiogram performed with an MDCT unit and a rapid injection pump. The image is displayed as a Maximum Intensity Projection (MIP) which is a useful way to view contrast-enhanced vessels or mineralized lesions


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CPD

The ultimate goal of this course is to provide the busy practitioner with the necessary clinical tools to take on the challenge of a neurological examination and to tackle common neurological complaints encountered in daily general practice.

The vet in general practice will learn to develop a logical step-wise approach to common neurological complaints and to take home some realistic management plans that can be easily applied in practice. We really want this course to be useful for veterinarians at any stage of their career, and will take delegates from the common clinical presentations of neurological cases (on video) to the

World-class speakers Simon Platt and Laurent Garosi will be taking their neuro know-how on the road to four locations in November. Here they talk about their aims for the course and their passion for communicating their specialist subject in innovative ways

Neurology to turn heads

NEUROLOGY ROADSHOW FOR BUSY PRACTITIONERSDerby 18 NovemberYorkshire 19 NovemberCardiff 22 NovemberSurrey 23 November

Member fee: 203.28 inc. VATNon-member: 304.91 inc. VAT

Specific topics covered: Is it spinal? Working up the weak: neuromuscular

diseases of the dog and cat Rock and roll: the many faces of vestibular

disease Seizures behaving badly Headaches: dealing with head trauma Dropped jaw, lockjaw and droopy faces

Visit www.bsava.com or email [email protected] or call 01452 726700 for more details.

work-up and treatment options available whether or not advanced technology and unlimited finances are on hand. We hope to take away the fear factor from these cases and discuss treating for the treatable.

Each clinical presentation will be illustrated by videos and interactive case studies. Indeed, the programme is mostly video-based which will make the course more interactive, engaging and practical. The hope is that delegates will return to their practice with more confidence to manage those common neurological complaints such as weakness, loss of balance, refractory seizures, paralysis or head trauma.

Simon and Laurent bring over 20 years of combined experience dealing with neurology cases on a daily basis. Both are RCVS recognised specialists in veterinary neurology. Laurent is a diplomate of the European College of Veterinary Neurology and currently company director and head of neurology service at Davies Veterinary Specialists, UK. Simon is a diplomate of both the European College of Veterinary Neurology and the American College of Veterinary Internal Medicine, subspecialty Neurology. He is currently associate professor at the College of

Veterinary Medicine at the University of Georgia, USA.

Both speakers have written extensively on veterinary neurology subjects, from brain tumours to strokes, in scientific articles in the most respected veterinary journals, in textbooks and the veterinary press. Simon is a co-editor of the BSAVA Manual of Canine and Feline Neurology. As speakers they are known for their comprehensive knowledge and passion for their subject, providing delegates with tools for the quick-thinking that is required for dealing with neurological cases.

Little known speaker facts

Laurent enjoys anything to do with planes and flies in his spare time.

Simon coaches his 3 daughters to swim and all three are USA state champions.

ABOUT THE SPEAKERS

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Brachycephalic breeds are popular in the UK, and include British and French Bulldogs, Pugs, Pekingese and Boston Terriers. The term means short-headed or broad-headed and refers to the characteristic appearance of the head. These dogs may also have dyschondroplastic development of the limbs, resulting in relatively short, bowed legs. The breed characteristics depend on breeding selectively for those offspring with abnormal development of the bones of the skull such that the head is shortened, but of a normal width. The soft tissues develop normally and, consequently, the majority of these dogs have some element of upper respiratory tract noise, including snoring and stridor due to obstruction and

pharyngeal folds and occasionally hypoplastic trachea) and the subsequent secondary problems (eversion of the mucosa of the lateral laryngeal saccules ventricles and laryngeal collapse).

PresentationMost dogs present in the first 3 years of life, with English Bulldogs and Pugs presenting at a younger age than other breeds.

Typical presenting complaints include more snoring and stridor than expected for the breed, coughing, reluctance to exercise, and dyspnoea when hot or excited.

Marked respiratory distress, cyanosis and collapse may occur in those dogs where owners have failed to recognise, or ignored, the clinical signs. Typical scenarios include exercising in hot weather or stressful trips to their veterinary practice where they may collapse in the waiting room.

Some dogs may have difficulty breathing on recovery from anaesthesia for another condition.

DiagnosisA provisional diagnosis is made in affected breeds with a typical history and supportive physical examination findings. In some cases the dog may not show any respiratory effort or distress on examination, in which case the owners description becomes very valuable. Clinical examination may confirm that the nares are stenotic, with reduced airflow at rest when the mouth is shut. Auscultation of the thorax may be impossible due to referred stridor from the upper airways.

The definitive diagnosis is based on examination of the pharynx and larynx under a light plane of anaesthesia, such that the dog is able to demonstrate movement of the larynx. However, in severely affected cases, these patients may pose problems for recovery from

Airway problems in brachycephalic dogs

Obstruction of the upper respiratory tract is a problem in many brachycephalic breeds. Alison Moores and Davina Anderson from Anderson Sturgess Veterinary Specialists in Winchester, outline the clinical approach to this disease

Figure 1: Stenotic nares in a French BulldogReproduced from the BSAVA Manual of Canine and Feline Head, Neck and Thoracic Surgery

oscillation of the redundant soft tissue.Most dogs will not have clinical

problems, although many owners limit exercise, especially in hot weather, to avoid the risk of collapse episodes. Breed websites suggest that these dogs are at abnormal risk of heatstroke, indicating a general acceptance of the fact that upper respiratory obstruction is a fact of life for these breeds. Brachycephalic airway obstructive syndrome or disease (BAOS) is the clinical presentation of upper airway obstruction due to a combination of the anatomical abnormalities in the upper respiratory tract of brachycephalic dogs and some cats. It comprises primary problems (stenotic nares (Figure 1), elongated soft palate, redundant

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anaesthesia and they should not be anaesthetised unless facilities are available to treat the condition or place a tracheostomy tube if necessary.

The difficulty is that most brachycephalic dogs will have some or all of the primary problems that define BAOS to a certain extent. However, most dogs with clinical signs have extreme anatomical abnormalities and may have secondary erythema and oedema of the mucosa, suggestive of turbulent airflow.

Anatomical abnormalitiesUp to 85% of brachycephalic dogs are found to have an elongated, and often thickened, soft palate, which is seen to obstruct the rima glottidis. The tip of the palate can often be seen vibrating on inspiration and may get sucked into the glottis. The palate can be assessed by fluoroscopy (which avoids anaesthesia), or by an accurately positioned lateral skull radiograph.

In the normal dog, resistance to airflow is primarily (76%) in the nasal cavity and the larynx contributes very little (4%). However, in the brachycephalic dog the extreme negative pressures required to draw air through the nasal cavity frequently exert sufficient pressure on the larynx to cause secondary changes, which then significantly increase air flow resistance in the laryngeal area as well.

Examination of the larynx is often hampered by the long soft palate, but can be achieved by use of a long laryngoscope to gently lower the epiglottis ventrally and a second laryngoscope or wooden tongue depressor to lift the palate dorsally. The lateral laryngeal ventricles lie rostral to the vocal folds, and eversion of the mucosal lining may occur secondary to chronic negative airway pressures in the pharynx and larynx. This should be assessed prior to intubation as restoration of normal

pressures often allows the mucosa to return to the ventricles. The mucosa causes obstruction of the ventral rima glottidis and in extreme cases can occlude half of its functional area.

Redundant pharyngeal folds cause a generalised narrowing of the pharynx that is unaffected by surgery and can only be managed by weight loss and reducing the dynamic effects of forced inspiratory effort. Finally, the dog is assessed for laryngeal collapse (Figure 2), a consequence of chronic negative airway pressures. This is more common in dogs that are older on

first presentation, even if their clinical signs are milder, reflecting the time it takes for collapse to manifest.

TreatmentSurgical treatment is ideally performed immediately after diagnosis, under the same anaesthetic, as it may be more difficult to recover the dog from anaesthesia without definitive surgery. Surgical management of these dogs aims to reduce the high resistance to inspiration in the nasal part of the upper respiratory tract, which involves nasal and palate (Figure 3) surgery. Whilst there are reports that only 50% of BAOS dogs have stenotic nares, the majority have a smaller nostril than normal dogs and these authors consider that all affected animals will benefit from surgery to widen the external nares and improve airflow. More recently, there have been reports of removal of nasal turbinates, but this involved specialist techniques and facilities.

Surgery is more difficult to perform in certain breeds, most notably the English Bulldog in which the soft palate is markedly thick and long; and cut and sew techniques without the use of haemostatic clamps can be associated with brisk haemorrhage. More recently, alternative procedures have been described which debulk the muscle of the hypertrophied palate as well as achieve shortening of its length. If the lateral laryngeal ventricles are everted, these may be removed at the same time in order to facilitate anaesthetic recovery, although they will recede if sufficient improvement to airflow has been achieved. Some surgeons also remove the tonsils if they are grossly enlarged.

Laryngeal collapse is generally treated conservatively, but the collapse will continue to contribute to airway obstruction and may progress. It has been suggested that laryngeal lateralisation (tieback) may

Figure 2: Severe laryngeal collapse. The cuneiform and corniculate processes meet in the midline, closing both the ventral and dorsal glottisReproduced from the BSAVA Manual of Canine and Feline Head, Neck and Thoracic Surgery

Corniculate process

Cuneiform process


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PUBLICATIONS

Airway problems in brachycephalic dogs

be beneficial for dogs with extreme collapse, although this is unproven, with permanent tracheostomy considered as a last resort.

The abundant pharyngeal folds mean that the pharynx may continue to look very narrow despite palatoplasty, and owners should be encouraged to keep these dogs on the slim side to reduce the impact of these folds. Clinically this may manifest as ongoing upper respiratory tract obstruction during recovery from anaesthesia. Recovery should therefore be slow and quiet, with the endotracheal tube left in place for as long as the dog tolerates it. The head can be supported on a sandbag and the tongue extended to aid breathing, but most dogs will breathe normally by the time they are conscious. Postoperative swelling of the mucosa is rarely a problem if the technique is performed by an experienced surgeon.

Associated conditionsWhilst most BAOS dogs respond well to surgical management, other contributory

factors may affect the long-term outcome. Brachycephalic dogs treated for BAOS may also have bronchial stenosis, although it is not thought to affect surgical outcome. Nasopharyngeal turbinates are present in 20% dogs with BAOS, especially Pugs, and unless facilities are available to resect them, they may continue to affect the level of nasal airway resistance. Epiglottic cysts and laryngeal granulomas are also described in English Bulldogs.

Finally, recent reports have shown an association between BAOS and gastrointestinal disease, with 50% of dogs having dysphagia and vomiting. Abnormalities (including hiatal hernia) and inflammatory disease are commonly found during upper gastrointestinal tract endoscopy and biopsy, and there is a relationship between the severity of respiratory disease and gastrointestinal signs. Affected animals benefit from 23 months of treatment with a histamine (H2) inhibitor and prokinetic, with prednisolone for cases with severe inflammation/fibrosis and an antacid and

surface protector if there is oesophagitis. Long-term therapy is required in 25% of dogs, and owners should be aware that this may be a significant factor in the postoperative outcome.

SummaryThe aim of surgery is to reduce airway obstruction such that collapse episodes do not occur. It is rare for affected dogs to have quiet respiration and most will still be unable to tolerate exercise in hot weather. Owners should remain conservative in their expectations and should continue to avoid exercise in hot weather. However, the majority of dogs recover without complication and achieve an improved quality of life. Brachycephalic breeds are charming and entertaining household pets and are likely to increase in popularity; however, the likelihood of the conformation defects being improved are slim and it would appear that veterinary involvement in these breeds is here to stay. n

References are available upon request.

SOFT TISSUE SURgERyThe Manuals of Canine and Feline Abdominal Surgery, Head, Neck and Thoracic Surgery, and Wound Management and Reconstruction highlight the most commonly performed techniques. Procedures undertaken by surgeons with more experience are also discussed, so that practitioners can better inform their clients. Step-by-step Operative Techniques detail the common procedures, with notes on patient positioning and preparation, instrumentation and postoperative care. Member price 49 Member price 44 Member price 49

Figure 3: Soft palate resection. (A) Allis tissue forceps are used to grab the centre of the soft palate and pull it rostrally. The grasped area will be removed. (B) A clamp is applied and used as a guide for cutting the soft palate. (C) The palate is oversewn loosely around the clamp, which is then removed. The larynx is now visibleReproduced from the BSAVA Manual of Canine and Feline Head, Neck and Thoracic Surgery

A B C


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PETSAVERSPETSAVERS

Improving the health of the nations pets

Petsavers produces a range of products specifically designed to meet the requirements of small animal practice. By buying Petsavers veterinary products you can ensure that all the profit goes directly back to Petsavers, helping to support the important work that Petsavers does in awarding grants to vets both in academia and practice to research the many conditions and illnesses that affect pets.

Heated padsPetsavers heated pads are designed to keep small pets warm in hospital and are also effective in minimising perioperative hypothermia. The pads are cheaper than an incubator and are less hassle than hot water bottles. The pads are easy to clean and run on a low voltage so that they can be left on constantly. A plug-in lead means it can be easily passed through the bars of a cage.

Protective collarsAssembly of the protective collars is easy and they are attachable to regular collars. The collars come in packs of ten and are available in a range of sizes starting at 7.5 cm through to 40 cm.

Petsavers veterinary products now available direct

We are pleased to announce that Petsavers veterinary products, previously available only through your veterinary wholesaler, are now available online direct through www.petsavers.org.uk

PETSAVERS CHRISTMAS CARDSAn order form for Petsavers Christmas cards is included in this edition of companion, with a special offer price of 3 for a pack of 10. These cards can also be ordered through www.petsavers.org.uk where you can also see the extended range of Petsavers Christmas cards.

Recovery blanketsPetsavers recovery blankets are made of metalized polyester, which means these blankets are tough and also retain 95% of radiated body heat. The blankets are ideal for preventing hypothermia in the perianaesthetic period and are also radiolucent, which means that diagnostic radiographs can be taken while the animal remains in the blanket. They are especially useful for trauma patients or hypothermic cases. The blankets are 2.14 m x 1.42 m and can be cut to fit smaller animals.

Pet carriersPetsavers wire carriers are suitable for cats and small dogs. The hinged lid allows full access to the interior of the carrier, so its easy to get pets in and out.

Petsavers also features inexpensive cardboard carriers that are popular with clients and easy to store.

water bottles. The pads are easy to clean and

plug-in lead means it

Pet carriers

The hinged lid

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The challenges ofvaccination in Asia

The WSAVA Vaccination Guidelines Group (VGG) was established in 2006 following recognition by the WSAVA Board and Scientific Advisory Committee (SAC) of the need for globally applicable recommendations on best practice for the vaccination of dogs and cats. During its first phase of activity (200607) a substantial guidelines document was produced which was published (Day et al., Journal of Small Animal Practice 2007; 48: 52841) and made freely available on the WSAVA website (latterly with Spanish and Polish translations). This document included a set of invaluable fact sheets related to the major canine and feline vaccine-preventable infectious diseases and a set of frequently asked questions (FAQs) related to vaccination practice.

The 2007 WSAVA vaccination guidelines had major global impact as assessed by a survey conducted of WSAVA member organisations in 2009. The availability of the guidelines, accompanied in some instances by local public pressure, led to many countries either formally adopting the WSAVA guidelines as national policy, or using the WSAVA guidelines as a basis for formulation of a national policy document. It is clear

that the controversy surrounding small companion animal vaccination has not diminished and that there is an urgent requirement to educate veterinary practitioners in this area. The members of the VGG are actively engaged in delivering national and international lectures to help address this demand.

The VGG was reconvened in 2009 for a second phase of activity which concluded in June 2010. During Phase II the initial task was the above-mentioned assessment of the global impact of the 2007 guidelines. The second major task was the production of an updated 2010 version of the guidelines. The document has been prepared and published (Day et al., Journal of Small Animal Practice 2010; 51: 33856). The revised document includes much new background information which was included following the feedback from the 2007 version. In addition, there is a new infectious disease fact sheet related to rabies virus and the number of FAQs has almost doubled. As a supplement to the revision we also make available a set of images, related to the major vaccine-preventable infectious diseases, that may be used by veterinary surgeons in their consultation room to emphasise the importance of vaccination to clients. The final outcome of Phase II was the release of a substantial information document for the owners and breeders of small companion animals in June 2010.

VGG Phase III: focus on AsiaDuring 200809, the chair of the VGG was privileged to lecture on the vaccination guidelines in Japan,

The WSAVA Vaccination Guidelines Group is reconvening for a new phase of activity, which will focus on the challenges related to infectious disease control in dog and cat populations in Asia

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WSAVA NEWS

Thailand, Singapore and India. These visits also provided unique opportunities to discuss with local practitioners, academic experts and officers of professional associations the issues and challenges related to vaccination in Asia.

The developing Asian countries provide particular challenges related to infectious disease control in dog and cat populations. The relevant issues include:

Stray animals: There are vast populations of stray animals within these countries and a lack of infrastructure to control these animals. There is a high prevalence of infectious disease within these stray populations diseases that are well controlled by vaccination in developed countries are commonplace in these areas.

Rabies: Rabies is a major cause of human mortality in these countries. Mandatory vaccination of the canine pet population is not routine and control is particularly challenging in the stray population.

The economics of pet ownership: Although in some burgeoning economies, such as India and China, greater affluence has led to increased pet ownership and a clientle prepared to finance this activity, the majority of owned animals in developing nations will not receive regular veterinary attention. The affluent clientle also has a distinct preference for particular small breeds of dog (e.g. the Pug in India, the Dachshund in Japan) and in some instances there is unregulated cross-border importation of stock (e.g. from Thai puppy farms) that frequently carry infectious disease. In most Asian countries, the dog is th

Companion October2010

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