Seborrhoea and otitis in a crossbred dog Author: Ross BondEditor: David Lloyd © European Society of...
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Transcript of Seborrhoea and otitis in a crossbred dog Author: Ross BondEditor: David Lloyd © European Society of...
Seborrhoea and otitis in a crossbred dog
Author: Ross BondAuthor: Ross Bond Editor: David LloydEditor: David Lloyd
© European Society of Veterinary Dermatology © European Society of Veterinary Dermatology
History | Signs | Differentials | Tests | Therapy | NotesHistory | Signs | Differentials | Tests | Therapy | Notes
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History - 1
HistoryHistory
• 9-year-old neutered female Collie cross dog
• Weight 43 kg
• Has had a dull, somewhat greasy coat for 4 years or more
• Has always been overweight but gaining more in last 2 years
History | Signs | Differentials | Tests | Therapy | NotesHistory | Signs | Differentials | Tests | Therapy | Notes
History - 2
HistoryHistory
• Decreased exercise tolerance attributed by owners to weight gain and arthritis (reluctance to exercise)
• Mild, recurrent head tremor noted on several occasions in the past year
• Chews and licks feet but not a severe problem, has itchy ears
• Dog is bright, appetite good, thirst unchanged (1.8-2.0 litres/day)
History | Signs | Differentials | Tests | Therapy | NotesHistory | Signs | Differentials | Tests | Therapy | Notes
History - 3
HistoryHistory
• Neomycin + betamethasone drops for otitis - little improvement
• Etiderm (ethyl lactate shampoo) - resolved pedal pruritus but erythema remained. Relapse after 6 weeks
• Prednoleucotropin (PLT), 1-2 twice daily for arthritis. Some improvement
• Efavet 660, 1 twice daily. No effect
History | Signs | Differentials | Tests | Therapy | NotesHistory | Signs | Differentials | Tests | Therapy | Notes
Clinical signs - 1
SignsSigns
• Bright, alert dog
• Heart rate 110 beats per minute
• Rectal temperature 100.5oC
• Mild generalised seborrhoea
• Mild erythema and hyperpigmentation of interdigital skin
• Moderate ceruminous otitis
History | Signs | Differentials | Tests | Therapy | NotesHistory | Signs | Differentials | Tests | Therapy | Notes
Clinical signs - 2
SignsSigns
• The dog was overweight
• The coat was long, thick and greasy
History | Signs | Differentials | Tests | Therapy | NotesHistory | Signs | Differentials | Tests | Therapy | Notes
Clinical signs - 3
SignsSigns
Anterior and dorsal views of the dog
History | Signs | Differentials | Tests | Therapy | NotesHistory | Signs | Differentials | Tests | Therapy | Notes
How would youapproach this case?
SignsSigns
• What are the next steps you would take?
• Make a list of your principle differential diagnoses
• List any samples you would collect
• List any tests you would perform to assist in making a definitive diagnosis
History | Signs | Differentials | Tests | Therapy | NotesHistory | Signs | Differentials | Tests | Therapy | Notes
Case investigation
DifferentialsDifferentials
• Principle differential diagnoses• Ewan - what would you include?
History | Signs | Differentials | Tests | Therapy | NotesHistory | Signs | Differentials | Tests | Therapy | Notes
Tests
TestsTests
• Tests
• Skin scrapings from feet ..... Ewan where else?
• Tape strips from interdigital spaces ......?
• Blood tests• Routine haematology• Biochemistry panel
History | Signs | Differentials | Tests | Therapy | NotesHistory | Signs | Differentials | Tests | Therapy | Notes
Results
TestsTests
• Scrapings did not reveal ectoparasites
• Tape strips demonstrated substantial numbers of Malassezia in the interdigital spaces
• Haematological and biochemical profiles were within accepted limits
History | Signs | Differentials | Tests | Therapy | NotesHistory | Signs | Differentials | Tests | Therapy | Notes
What now?
• What treatment, if any, should you now institute?
• What are now your principle differential diagnoses?
• Are there any other samples you would collect?
TestsTests
History | Signs | Differentials | Tests | Therapy | NotesHistory | Signs | Differentials | Tests | Therapy | Notes
Initial therapy
• Ectoparasitism was deemed unlikely
• Malassezia numbers indicated infection necessitating therapy
• Owner was instructed to bathe the feet using Malaseb Shampoo twice weekly. Allowing a 10 minute contact time before rinsing.
TestsTests
History | Signs | Differentials | Tests | Therapy | NotesHistory | Signs | Differentials | Tests | Therapy | Notes
What is yourdiagnosis?
• What is your principle diagnosis?
• Do the investigations permit a definitive diagnosis?
• Are there any additional investigations which you think may need to be done?
TestsTests
History | Signs | Differentials | Tests | Therapy | NotesHistory | Signs | Differentials | Tests | Therapy | Notes
Further tests
TestsTests
• Total T4 and endogenous TSH were measured,
• Results
• Total T4 = 12.7 µmol/l (13-52)
• Endogenous TSH = 0.47 µg/ µl (<0.41)
• What does this mean?
History | Signs | Differentials | Tests | Therapy | NotesHistory | Signs | Differentials | Tests | Therapy | Notes
Diagnosis
• Hypothyroidism diagnosis supported by:
• Low total T4 and elevated TSH levels
• Dog overweight
• Poor exercise tolerance
• Susceptibility to skin infection
• Hypertrichosis
TestsTests
History | Signs | Differentials | Tests | Therapy | NotesHistory | Signs | Differentials | Tests | Therapy | Notes
How would you deal with this case?
• What is your prognosis?
• How will you advise the owner?
• What treatment would you institute?
TestsTests
History | Signs | Differentials | Tests | Therapy | NotesHistory | Signs | Differentials | Tests | Therapy | Notes
Prognosis
• Prognosis is good• Hypothyroidism normally responds well to therapy
with thyroxine
• Hypothyroidism may explain many, if not all of the clinical problems in this case
TestsTests
History | Signs | Differentials | Tests | Therapy | NotesHistory | Signs | Differentials | Tests | Therapy | Notes
Therapy
TherapyTherapy
• Thyroxine administered at 10 ug/kg twice daily for 12 weeks then the 4 hour post-T4 basal plasma total T4 measured and gave a value of 35 nmol/l
• Maintenance therapy was then established at 15 ug/kg of thyroxine twice daily
• Response. Loss of all hair apart from a short 2-3 cm coat, over a 3 month period
History | Signs | Differentials | Tests | Therapy | NotesHistory | Signs | Differentials | Tests | Therapy | Notes
Response to therapy
• Coat then grew gradually to form a normal coat
• Weight decreased to 32kg over 12 months
• Exercise tolerance and mobility improved
• Head tremor absent
• Coat improved but still some greasiness
• Continuing mild otitis externa
• No pruritus
TherapyTherapy
History | Signs | Differentials | Tests | Therapy | NotesHistory | Signs | Differentials | Tests | Therapy | Notes
Points to consider - 1
NotesNotes
• How do you asses the significance of Malassezia• Tape strips and surface culture methods only identify
superficial populations. Some cases without elevated surface populations will respond to anti-yeast therapy
• Could ketoconazole have been used to deal with the Malassezia?
• Signs were mild and did not justify ketoconazole an unlicensed product.
• Ketoconazole inhibits steroidogenesis and would have complicated the interpretation of subsequent endocrine assessments
History | Signs | Differentials | Tests | Therapy | NotesHistory | Signs | Differentials | Tests | Therapy | Notes
Points to consider - 2
NotesNotes
• Why is hypertrichosis sometimes a feature of hypothyroidism?• Thought to be caused by slowed hair cycle turnover -
telogen hairs not shed and resultant thick coat
• It is a common feature of equine hypothyroidism
• In dogs it is seen particularly in setters
History | Signs | Differentials | Tests | Therapy | NotesHistory | Signs | Differentials | Tests | Therapy | Notes
Review
NotesNotes
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