Neurological Examination and Diagnostic Testing in Birds and Reptiles

CLINICAL TECHNIQUE

NEUROLOGICAL EXAMINATION AND DIAGNOSTICTESTING IN BIRDS AND REPTILESCraig Hunt, BVetMed, CertSAM, DZooMed, MRCVS

gin.tengalp

sis

re

minsriotio

being ectothermic, have reexes that are inuenced by body temperature; therefore, reptiles should be1557-5063/14/2101-$30.00http://dx.doi.org/10.1053/j.jepm.2014.12.0053 4 Journal of Exotic Pet Medicine 24 (2015), pp 3451 2014 Elsevier Inc. All rights reserved.

From the Chine House Veterinary Hospital, Leicestershire, England, UK.Address correspondence to: Craig Hunt, BVetMed, CertSAM, DZooMed, MRCVS, Chine House Veterinary Hospital, Sileby Hall, CossingtonRoad, Sileby, Loughborough, Leicestershire LE12 7RS, UK. E-mail: [email protected] examination on a bird or reptilepatient owing to differences in anatomy andtemperament.Neurological disease signs in birds and reptiles

are often nonspecic, consequently a diseasediagnosis using external clinical signs alone israrely achieved. Birds and reptiles mask illness, orowners are unaware of subtle disease signs untilwell advanced, resulting in many of these patientsbeing presented to the veterinary clinic in a criticaldisease state. These critical presentations, withoften one or more life-threatening disease

organophosphates, pyrethroids, drugs and plants),infection (e.g. viral, parasitic, bacteria and fungus),neoplasia, congenital abnormalities andcardiovascular, hepatic and renal disorders.Metabolic diseases (e.g., hypocalcaemia) andmusculoskeletal disorders (metabolic bone disease)often present with similar clinical signs and may bedifcult to distinguish from primary neurologicaldisease without further investigation; hypothermiamay also mimic neurological disease in reptiles.The evaluation of neurological disorders in

reptiles and birds follows a similar pattern to thatmodications may be required when performing a may be caused by toxins (e.g., heavy metals,mammals, and the neurological examination maybe approached in a similar manner to thatdescribed for dogs and cats.15 Naturally some

Neurological disease in both birds and reptiles isoften secondary to inadequate husbandry (e.g.,temperature) and nutrition (birds and reptiles) butexamined in an environment that is within their selected body temperature range.

Although there are few exceptions, theneuroanatomy of reptiles and birds is similar to

problems, typically require extensive treatmentbefore a full neurological assessment.Abstract

Neurological dysfunction is a frequently presentinlogical signs are rarely pathognomonic, often requirinvolved diagnostic tests to achieve a diagnosisdemeanour present unique challenges to the veneurological disease signs. Despite these challeexamination can often be accomplished with minimis essential to formulate an appropriate investigativeand to provide the owner with an accurate progno

Key words: avian; examination; neurological; reex;

Abasic knowledge of the normal anatosystem is essential to enable the veterdisease in these animals.1-14 Variationtolerance to handling between the vaneurological examination and localisasign in avian and reptile patients. Clinical neuro-g the attending veterinary surgeon to perform moreVariations in patient anatomy, physiology andrinarian evaluating the bird or reptile that hases, a well-structured physical and neurologicalequipment. A structured neurological examinationlan and therapeutic regime for these difcult cases. Copyright 2014 Elsevier Inc. All rights reserved.

ptile

y and physiology of the reptile and avian nervousary clinician to accurately diagnose neurologicalin anatomy, physiology, temperament, andus avian and reptile species can make then of lesions challenging in these patients. Reptiles,

used for other species and begins by obtaining athorough history and performing a detailedexternal physical examination. Further assessmentof the patient will often include one or all of thefollowing diagnostic modalities: haematology andserum biochemistry, radiography, ultrasonagraphyand endoscopy. Additional diagnostic tests such asheavy metal analysis, serology/PCR for infectiousdiseases and cerebral spinal uid analysis may berequired in select bird or reptile neurological cases.Increasingly, computed tomography and magneticresonance imaging are becoming more accessibleand may give detailed images of the centralnervous system, though the small size of manypatients can be a limiting factor in the use of theseadvanced imaging modalities. Electromyographyand nerve conduction studies may be useful inselected cases, but these tests are rarely available inthe typical veterinary hospital.

HISTORY

All but the most compromised of avian and reptilepatients will have normal behaviour under mild tomoderate conditions of stress (e.g., veterinaryvisit). Observation of patients from afar in aquietened room, preferably after a period ofacclimatisation, allows the patient to relax anddisplay abnormal clinical signs, if present, orbehaviour, which may otherwise go unnoticed.Whilst the patient is acclimatising, a thoroughhistory may be obtained from the owner, giving

TABLE 1. Equipment list

(1) Pen torch(2) Hypodermic needles(3) Mosquito forceps(4) Towel(5) Gloves(6) Perch(7) Digital thermometer(8) Mouth gags(9) Cotton-tipped applicatorsthe clinician time to evaluate the animal from adistance. This hands-off evaluation will allow theveterinarian to ascertain the patients ability tocope with restraint and physical examination and/or whether steps should be taken to medicallystabilise the patient before handling.Important aspects of the history pertaining to the

neurological patient include nutritional offering(including any supplements), what it is eatingfrom, and what is being fed; the patients ability torecognise and obtain food in an appropriatemanner for that particular species; access to toxins;

Hunt/Journal of Exotic Pet Medicine 24 (2015), pp 3451recent administration of medication; provision ofappropriate ultraviolet light (many reptiles andsome birds); and access to suitable thermalgradients (reptiles).

CLINICAL EXAMINATION

Much of the neurological examination may beincorporated into a well-structured physicalexamination. Following the physical examination,the clinicians goal is to localise the disease processto one or more areas of the nervous system. Asstated previously, the natural behaviour of manyavian and reptile patients routinely complicates theveterinarians ability to accomplish the task oflocalising the lesion associated with theneurological disease process.The aim of the neurological examination is to

localise any lesion to the brain or 1 of 4 majorspinal cord divisions. The spinal cord divisionsdescribed in birds and reptiles are the cervical,brachial, thoracic and lumbosacral plexus; snakesand presumably limbless lizards have reduced orabsent brachial and sacral plexuses.Accurate localisation of pathology allows the

clinician to determine which diagnostic test willconrm a disease diagnosis. Once a denitivedisease diagnosis has been made, the veterinariancan form a prognosis and institute a treatment planthus avoiding the unnecessary use of sometimesexpensive and invasive tests.

HOW TO PERFORM A NEUROLOGICALEXAMINATION

Equipment required to perform a properneurological examination on reptile and avianpatients is provided in Table 1. Cranial nervefunction tests for birds and reptiles and signs ofneurological dysfunction are in Tables 2 and 3,respectively.

Step-by-step guide for birds:

(1) Observe the patient from a distanceassess posture and symmetry of the head, facialfeatures and body, demeanour, level of alertnessand responsiveness to surroundings (Fig. 1).(2) Make a loud noise such as clapping ofhands or dropping keys onto oor whilst the birdis otherwise occupied to assess hearing.(3) Approach patient calmly and evaluateresponse to determine visual acuity and alertness.Note: birds with unilateral blindness often turnthe blind side away from the examiner, thereforethe blind eye is not easily observed.3 5

TABLE 2. Avian cranial nerves and their function and clinical tests to determine normal function and clinicalsigns of dysfunction

Nerve Function Clinical Test Sign of Dysfunction

I Olfactory Sensoryolfaction Response to odour suchas alcohol; patientshould avoid noxiousodour

No response; beware thataversion is not alwaysowing to odour but tophysical irritation

II Optic Sensoryvision Menace reex Absent blink and/oraversive movements ofhead and body inresponse to a threat.

Inability to avoid objectsplaced in path

III Oculomotor Motorextrinsic ocularmuscles and uppereyelid muscle

Eyeball position andmovement

Ventrolateral deviation

Parasympatheticintrinsic ocular muscle

Menace reex Drooped upper eyelid

Pupillary light reex Dilated pupilIV Trochlear Motorextrinsic ocular

muscleEyeball position and

movementDorsolateral deviation

V Trigeminal:Ophthalmic branch Sensory (upper lid,

forehead skin, nasalcavity and upper beak)

Response to touch,palpebral reex

Lack of sensation

Sensory (both lids, hardpalate, nasal cavityand lateral upperbeak)

Unable to blink

Maxillary branch Motor (orbicularis, lowerlid and chewing)

Menace reex Unable to close jaw

Mandibular branch Sensory (lower beak skincommissures)

VI Abducens Motorextrinsic ocularmuscles and nictitans

Eyeball position andmovement

Medial deviation

Nictitans immobilityVII Facial Motorfacial expression Facial asymmetry

Sensorytaste Poor tasteParasympatheticmost

glands of the headDecreased secretions

VIII Vestibulocochlear Sensoryhearing Response to sound No response to sound,head tilt, nystagmus,abnormal posture andpoor righting reex

Sensorybalance andcoordination

Oculocephalic reex

Righting reexIXa Glossopharyngeal Sensorytaste and

sensation in thetongue and trachea

Gag reex No gag reex

Motorpharynx, larynx,crop and syrinx

Dysphagia and voice loss

Xa Vagus Sensorylarynx, pharynxand viscera

Gag reex No gag reex

Motorlarynx, pharynx,oesophagus and crop

Oculocardiac/vago-vagalreexapply pressureto both eyes for severalminutes and check fordecreased heart rate

Inability to swallow,regurgitation, voicechange, increasedheart rate and no cropmotility

3 6 Hunt/Journal of Exotic Pet Medicine 24 (2015), pp 3451

,(4) If tame, encourage the bird to step up ontoand off a perch or hand (glove for raptors)noting coordination and strength of legs and grip(Fig. 2).(5) Perform menace reex by obscuring thevision in one eye with one hand whilst making athreatening gesture close to the opposite eye withthe other hand, taking care not to cause any airmovement that may be detected by the bird(Fig. 3).(6) Drop and/or throw a ball of cotton woolin the patients normal eld of vision and assessresponse. Assessment of the response to beingshown a favourite food item may also beperformed and is especially useful in raptors andcorvids.(7) Assess the pupillary light reex (PLR) byshining a bright light into each eye and assesspupil response (Fig. 4). Note: there is noconsensual response in birds.(8) Whilst on hand/glove, rotate the hand inall directions to assess balance and strength ofgrip (Fig. 5).(9) Lower the hand quickly to stimulate a fall;the normal bird should extend wings ap tomaintain balance. Observe for symmetry andspeed with which the wings are returned to a

TABLE 2. Continued

Nerve Function

Parasympatheticglands,heart and viscera

XIa Accessory Motorsupercial neckmuscles

XIIa Hypoglossal Motortongue, tracheaand syrinx

Modied with permission from Clippinger TL, Bennett RAneurodiagnostic techniques. J Av Med Surg 1996;10(4):221-47.aAnastamoses present involving cranial nerves IX-XII.normal resting position.(10) Palpate legs for symmetry, muscle massand tone.(11) Pinch the toes of each foot in turn andasses the withdrawal response and determinewhether there is any conscious perception ofpain (Fig. 6); caution must be observed by theexaminer. Raptors may strike out with theirfeet, and parrots may attempt to bite.(12) At this point, some patients may berestrained in a towel to allow access to thehead whilst limiting wing and leg movement,which allows more control over the patient(Fig. 7).

Hunt/Journal of Exotic Pet Medicine 24 (2015), pp 3451(13) Assess the palpebral reex by lightlytouching the medial canthus with a nger orcotton-tipped applicator (Fig. 8).(14) Pinch the skin over the face and cere toassess facial sensation using nger or mosquitoforceps (Fig. 9).(15) Open the beak to assess jaw tone and oralsecretions, and observe the glottis and tongue forsymmetry and normal movement (Fig. 10).(16) In nonpsittacine birds, place theindex nger of the hand restraining the head inthe commissure of the beak to maintain thebeak in an open position whilst manipulatingthe tongue and glottis with a cotton-tipapplicator or a nger on the free hand toassess the gag reex and tongue-grab reex(Fig. 11). In psittacine birds, the oral cavity isbest opened and examined with the aid of asuitable speculum to avoid injury to theexaminer.(17) Assess the oculocephalic reex by movingthe head from side to side whilst maintaining thehead in a horizontal plane. In healthy birds,nystagmus should be observed with the fastphase in the direction of the head movement.(18) Palpate the neck for muscle mass and toneand palpate the crop.

Clinical Test Sign of Dysfunction

Inability to open andclose the glottis

Poor neck movement

Tongue grab Tongue deviation

Platt SR. The avian neurological examination and ancillary(19) Extend each wing individually and pinchthe wing tip to evaluate a withdrawal responseand pain perception, then release the wingobserving how quickly the bird retracts the winginto the normal resting position (Fig. 12).(20) Assess the muscle tone of the vent andthen pinch or prick the vent with a needleinthe normal bird, the vent sphincter shouldconstrict (Fig. 13).(21) Whilst restraining the bird from abovearound the shoulders with the wings heldagainst the body but with the legs unrestricted,bring the feet towards the examining table or aperch to evaluate the placing reex (Fig. 14);

3 7

TABLE 3. Reptile cranial nerves and their function and clinical tests to determine normal function and clinicalsigns of dysfunction

Nerve Function Clinical Test Sign of Dysfunction

I Olfactory (including thevomeronasal nervebranch)

Sensoryolfaction Patient should avoidnoxious odour such asalcohol or showability to nd foodwhen eyes are covered

No response; beware thataversion is not always dueto odour but to physicalirritation

II Optic Sensoryvision Menace reex Absent blink (in species witheyelids) and/or aversivemovements of head andbody in response to athreat. Inability to avoidobjects placed in path

III Oculomotor Motorpulls eye in orx gaze;

Eyeball position Abnormal eyeball position,movement and pupil

Parasympatheticcontrols iris andciliary body

Menace reex Shape/size; dilated pupil

Pupillary light reex

IV Trochlear Motordraws gazeanteriorly anddorsally

Eyeball position Abnormal eyeball positionand movement

V TrigeminalOphthalmic branchand maxillary branch

Sensoryfrom skinaround eye andmouth. Sensory pitsof pit vipers andboids.

Assess sensation aroundface, lower lid andnasal area

Lack of sensation

Mandibular branch Motorjaw adductormuscles, muscles ofskin around teeth-bearing bones insnakes andintermandibularis (inoor of mouth)

Assess normal jawclosure and buccalpumping.

Unable to close jawAbsent buccal pumping

VI Abducens Motordraws gazeposteriorly

Eyeball position Abnormal eyeball positionand movement

VII Facial Sensoryfrom skin andmuscle around theear, upper jaw andpharynx.

Assess sensation Unable to move eyelids (inspecies with eyelids).

Motorsupercial neckmuscles andmandibular depressor

Palpebral reex Unable to open mouthvoluntarily

Voluntary opening ofmouth

VIII Auditory/Acoustic Sensoryhearing Response to sound No response to sound, headtilt, nystagmus, abnormalposture and poor rightingreex

Sensorybalance andcoordination

Oculocephalic reex

Righting reex


Ga

Ex

Ga

Oc

AsTABLE 3. Continued

Nerve Function

IX Glossopharyngeal Sensorytaste andsensation in thepharynx

Motorcontrols tonguemuscles

X Vagus Sensory and motor to theglottis, heart andviscera

XI Spinal accessory Motortrapezius andraptors may be hooded to increase testsensitivity.(22) With the bird still restrained asdescribed before and with one leg held upagainst the body wall, perform the hoppingtest on the standing leg by manoeuvring thepatients body to change the centre of gravitylaterally, medially, forward and backwardwhile measuring the compensatory movementsof the leg (Fig. 15).(23) With the bird standing but with the bodybeing supported, knuckle the toes of one footover and evaluate how long it takes for the birdto return the foot to a normal position (Fig. 16);alternatively, place a card under the foot andslide it laterally and evaluate the speed withwhich the bird returns the foot to a normalposition.(24) Finally, pinch the skin or gently pull at thefeathers along either side of the dorsal midlineworking methodically cranial to caudal or vice

sternomastoidmuscles

XII Hypoglossal Motorhyoid musclesand tongue

To

Adapted with permission from Wyneken J. Reptilian neurology: aPract 2007;10:837-853.

Hunt/Journal of Exotic Pet Medicine 24 (2015), pp 3451Clinical Test Sign of Dysfunction

g reex No gag reex

amine tongue foractive protrusion andretraction and observeability to swallow

Absent or abnormal tonguemovements

Dysphagia

g reex No gag reex

ulocardiac/vago-vagalreexapply pressureto both eyes forseveral minutes andcheck for decreasedheart rate

Inability to swallow,regurgitation and ileus

Inability to open and closethe glottis

sess muscle tone in Poor muscle tone in neck andversa to assess cutaneous pain sensation. Note:birds lack a panniculus reex.

Step-by-step guide for reptiles:

(1) Observe the patient from a distanceassess posture and symmetry of head, facialfeatures and body, demeanour, level of alertnessand responsiveness to surroundings. In snakesand monitor lizards, note the presence or absenceof tongue icking (Fig. 17).(2) Make loud noise such as clapping of handsor dropping keys onto the oor whilst the patientis otherwise occupied to assess hearing. Note:many normal reptiles may not demonstrate avisible response.(3) Approach patient calmly and observeresponse to assess vision and alertness. Note:many reptiles, especially lizards with unilateralblindness, often turn the blind side away fromthe examiner.

dorsal neck andshoulders (difcult toassess in snakes andchelonia)

shoulders.Poor neck movement

ngue grab Tongue deviation

natomy and function. Vet Clin North Am Exot Anim

3 9

FIGURE 1. Before hands-on physical examination, the patient should be examined from a distance. (A) Mute swan(Cygnus olor) demonstrating neck weakness. (B) Harris hawk (Parabuteo unicinctus) presented with seizures because ofhypoglycaemia. (C) A juvenile emu with hindlimb paresis resulting from zinc toxicity after ingesting several zincscrews and nails. (D) An aged Toulouse goose (Anser anser domesticus) with multiorgan failure demonstratingtorticollis. (E) Wild European kestrel (Falco tinnunculus) found unable to y presented with knuckling of the right footand absent withdrawal reex; note also the soiling of the tail feathers resulting from an inability to perch and preenappropriately. (F and G) An aged blue-and-gold macaw (Ara ararauna) with pulmonary carcinoma demonstratingHorner syndrome in the right eye (ptosis of the upper eyelid and miotic pupil); compare with the left eye of thesame bird.


lu

FIGURE 4. Pupillary light reex being assessed on adomestic chicken; this test is best performed early in theexamination to minimise conscious reaction of the pupil,which often occurs during excitement or stress in birds.(4) If tame, encourage the patient to climb uponto a perch/branch (chameleons/snakes) or

FIGURE 2. Hybrid falcon (Falco cherrug Falco rusticostepping up onto a T perch from the gloved hand.hand (smaller lizards) noting coordination,muscle tone and strength of grip (Fig. 18).(5) Perform menace reex by obscuring thevision in one eye with one handwhilst making a threatening gesture close to

FIGURE 3. Menace reex being performed on a domestichicken; note the head reaction.

Hunt/Journal of Exotic Pet Medicine 24 (2015), pp 3451s)c

FIGURE 5. Hybrid falcon (Falco cherrug Falco rustico-lus) perched on the gloved hand; the hand is rotated intodifferent positions to alter the birds centre of gravity,forcing the bird to make compensatory movements toretain balance.

4 1

FIGURE 6. The withdrawal reex performed on ahybrid falcon (Falco cherrug Falco rusticolus)noting withdrawal response and any consciousperception.

FIGURE 7. African grey parrot (Psittacus erithacus) beingwrapped in a towel to allow control over the head; thisprocedure is not always necessary depending on thepatients demeanour.

FIGURE 8. Palpebral reex being elicited in a domesticchicken by gently touching the medial canthus with acotton-tipped applicator.

4 2FIGUchicskin

Huthe opposite eye with the other hand takingcare not to cause any air movement that maybe detected by the reptile (Fig. 19)(6) Drop and/or throw a ball of cotton wool

in the patients normal eld of vision and

RE 9. Facial sensation being assessed in a domesticken by gently pinching the comb, wattles, cere and facialusing ngers or forceps.

nt/Journal of Exotic Pet Medicine 24 (2015), pp 3451

(10) Extend each limb individually and pinchthe toes to measure the withdrawal responseand pain perception (Fig. 23); then release thelimb whilst in extension observing howquickly the limb is retracted into the normalresting position (caution must be observed bythe examiner as some species may attempt tobite or tail whip).(11) Depending on the demeanour of thepatient and to gain more control over the patient,either restrain in-hand or wrap the patient in atowel to allow access to the head whilst limitingleg and tail movement. Depending on the sizeand species, snakes may be allowed to coilaround the examiners arm whilst being heldbehind the head with the examiners hand or thebody is supported by one or more assistantswhilst the examiner holds the head.(12) Assess the palpebral reex by lightly touchingassess response. Judging an animals responseto being offered a favourite food item (e.g.,live insects) may be especially useful ininsectivores (e.g., chameleons) (Fig. 20). Note:it may be difcult to completely differentiatean olfactory response from a visual one insome species.(7) Assess the PLR by shining a bright lightinto each eye and assess pupil response (Fig. 21).Note: the consensual response may be difcult toappreciate in reptiles.(8) Whilst on hand/perch, rotate hand in alldirections to assess balance and grip. Snakesshould be allowed to move from hand to handand determine strength of coiled grip andstrength in extension as the snake traverses thegap (Fig. 22).(9) Palpate body and limbs (where present)for symmetry, muscle mass and tone.

the medial canthus with a nger or cotton-tipped

FIGURE 10. Jaw tone being assesses in a domesticchicken by gently opening the beak; the oral cavityand glottis are assessed for symmetry and presence ofany lesions.

Hunt/Journal of Exotic Pet Medicine 24 (2015), pp 3451FIGURE 11. In nonpsittacine birds, the index nger ofthe hand restraining the head is placed in the commis-sure of the beak to maintain the beak in an openposition whilst manipulating the tongue and glottiswith a cotton-tip applicator or a nger on the free handto assess the gag reex and tongue-grab reex. Inpsittacine birds, the oral cavity is best opened andexamined with the aid of a suitable speculum to avoidinjury to the examiner.4 3

FIGURE 12. Wing of a domestic chicken being exten then released to assess proprioception; the test isrepeated, and the wing tip is pinched to evaluate the al reex making note of any conscious perceptionof pain.

FIGURE 13. Cloacal muscle tone and pinch reex beingmeasured in a domestic chicken.

4 4ded andwithdrawFIGURE 14. Placing reex in a domestic chicken (rabe hooded to increase test sensitivity).

Hunt/Journal of Exotic Pet Medicine 24 (2015),ptors maypp 3451

applicator (Fig. 24). Note: it is not possible to assessthe palpebral reex in species without eyelids suchas snakes and many gecko species.(13)Pinch the skin over the face and head toassess facial sensation using nger or mosquitoforceps or by pricking with a needle.(14) Open the oral cavity to assess jaw toneand observe the glottis opening and tongue forsymmetry and normal movement and assess oralsecretions (Fig. 25).(15) For smaller terrestrial tortoises,place the index nger in the commissure of thebeak to maintain the mouthopen and manipulate the tongue and glottiswith a cotton-tippedapplicator to assess the gag reex and tongue-grab reex (Fig. 26). A speculum may berequired for larger species and/or those withsharp teeth and/or a powerful bite.(16) Assess the oculocephalic reex by movingthe head from side to side whilst maintaining the

FIGURE 15. The hopping test is being performed on adomestic chicken.

Hunt/Journal of Exotic Pet Medicine 24 (2015), pp 3451head in a horizontal plane. In healthy reptiles,nystagmus should be observed with the fastphase in the direction of the head movement.(17) Palpate along the neck and spine formuscle mass and tone.(18) Assess the muscle tone of the vent and thenpinch or prick the vent with a needle (Fig. 27); inthe normal reptile, the vent sphincter shouldconstrict and the tail will often move to the side.(19) Roll the patient on both its left and rightsides to assess the righting reex (Fig. 28).(20) If the patient is a species with limbs,restraint should be achieved without restrictinglimb movement; bring each foot in turn towardsthe examination table or a perch (chameleons) to

FIGURE 16. Proprioception being assessed in a domes-tic chicken by knuckling the toes of one foot over andassessing speed and coordination with which the foot isreturned to normal standing position.assess the placing reex (Fig. 29).(21) With the patient in a normal standingposture, hold the limbs on one side against thebody wall and push the patient in a lateraldirection (away from the side with the limbsrestrained), repeat for the other side and evaluatethe compensatory movements of the limbs(Fig. 30).(22) Restrain the patient with only one footstanding on the examination table, and performthe hopping test on the standing leg bymanoeuvring the patients body to change thecentre of gravity laterally, medially, forward, andbackward to calculate the compensatorymovements of the limb (Fig. 31).(23) With the patient standing but with the bodysupported, knuckle the toes of one foot over andevaluate how long it takes for the patient to returnthe foot to a normal position (Fig. 32);alternatively place a card under the foot and slide

4 5

FIGURE 17. Before hands-on physical examination, the reptile patient should be examined from a distance. (A)Dwarf reticulated python (Python reticulatus) with uraemic encephalopathy presented with seizures and incoordina-tion. (B) Bosc monitor (Varanus exanthematicus) with severe nutritional secondary hyperparathyroidism (NSHP)presenting with muscle fasciculation; note the abnormal posture, maloccluded jaw and deformity of the spine. (C)Leopard gecko (Eublepharis macularius) presented with dysecdysis; this patient was suffering from NSHP. (D) Femalebearded dragon (Pogona vitticeps) demonstrating a head tilt and circling to the left. (E and F) Veiled chameleon(Chamaeleo calyptratus) with a sunken left eye. (G) Corn snake (Pantherophis guttatus) with strabismus during recoveryfrom general anaesthesia.


FIGURE 18. Panther chameleon (Furcifer pardalis) being encouraged to reach out and walk from one hand toanother.

FIGURE 20. A food item (arrow) being offered to a pantherchameleon in an attempt to assess vision.

FIGURE 19. Menace reex being performed on a Russian tortoise (Agrionemys horseeldii).

FIGURE 21. Pupillary light reex testing in a Russiantortoise.

Hunt/Journal of Exotic Pet Medicine 24 (2015), pp 3451 4 7

FIGURE onexamine ue

FIGUREpantherany cons

4 822. (A) Tail grip being assessed in a panther chameled in a king snake (Lampropeltis getula); note also the tongit laterally and evaluate the speed with whpatient returns the foot to a normal positio(24) Finally, pinch the skin along eithethe dorsal midline working methodicallyto caudal or vice versa to assess cutaneousensation. Note: reptiles lack a panniculus

23. The withdrawal reex performed on achameleon noting withdrawal response andcious perception.ich then.r side ofcranials painreex.

FIGUtorto

Hu; (B) strength of coiled grip and demeanour beingicking, which suggests a degree of alertness.USEFUL TIPS

Some reptile species have the potential to causesignicant injury to the examiner, especially duringexamination of the head (e.g., monitors, iguanas,large boids and venomous species) whereas somespecies (e.g., iguanas) may attempt to whip the

RE 24. The palpebral reex being assessed in a Russianise.


FIGURE 25. Determination of a Russian tortoises jaw tone canbe achieved by gently opening the mouth; the oral cavity andglottis opening are assessed for symmetry and the presence ofany lesions.

FIGURE 26. Gag reex and tongue-grab reex being assessed ina Russian tortoise using the index nger as a speculum.

FIGURE 27. (A) Cloacal tone and pinch reex being assessed in a Russian tortoise. (B) Prolapsed hemipenes in a king snake withneoplasia of the spine.

FIGURE 28. Righting reex being assessed in red iguana(Iguana iguana); this patient failed to return to a normalstanding position.

FIGURE 29. Placing reex being assessed in a Russiantortoise.

Hunt/Journal of Exotic Pet Medicine 24 (2015), pp 3451 4 9

examiner with their tail. Raptors may strike withtheir talons, and psittacines and some raptors(especially vultures and eagles) can deliver asubstantial bite. Ratites can deliver a powerful kick,which can cause serious injury.

FIGURE 30. Hemistanding being assessed in a Russian tortoise.

FIGUREtortoise.

FIGdragspeenor

5 0The ciliary muscle is under voluntary control inbirds and reptiles giving these species the ability tooverride the PLR particularly when the animal isstressed. The PLR is best performed early in theexamination, preferably with the patient31. Hopping test being performed on a Russian

HuREFERENCESSUMMARY

Birds and reptiles present unique challenges to theveterinarian attempting to investigate and diagnoseneurological conditions in these species.Performing an adequate neurologic examinationon avian and reptile patients is perceived by manyveterinarians as a formidable challenge owing tothe wide variations in anatomy, physiology anddemeanour; however, success can be achieved byadapting recognised examination techniques usedfor dogs and cats.unrestrained, to minimise stress effect on the testresults.

URE 32. Proprioception being evaluated in a beardedon by knuckling the toes of one foot over and assessingd and coordination with which the foot is returned to amal standing position.1. Bennet RA: Neurology, in Ritchie BW, Harrison GJ,Harrison LR (eds): Avian Medicine: Principles and Appli-cation. Lake Worth, FL, Wingers Publishing, pp728-747, 1994

2. Dubbeldam JL: Motor control system, in Whittow GC(ed): Sturkies Avian Physiology (ed 5). San Diego, CA,Academic Press, pp 83-100, 2000

3. Gunturkun O: Sensory physiology: vision, in Whittow GC(ed): Sturkies Avian Physiology (ed 5). San Diego, CA,Academic Press, pp 1-20, 2000

4. King AS, McClelland J: Birds: Their Structure and Function(ed 2). Bath, UK: Bailliere Tindall, pp 237-315, 1984

5. Kuenzel W: The autonomic nervous system of avianspecies, in Whittow GC (ed): Sturkies Avian Physiology(ed 5). San Diego, CA, Academic Press, pp 101-122, 2000

6. Mason JR, Clark L: The chemical senses in birds, inWhittow GC (ed): Sturkies Avian Physiology (ed 5). SanDiego, CA, Academic Press, pp 39-56, 2000

7. Molenaar GJ: Anatomy and physiology of infrared sensi-tivity of snakes, in Gans C, Ulinski P (eds): Biology of theReptilian, vol. 17 (neurology C). Chicago, IL, University ofChicago Press, pp 367-453, 1992


8. Necker R: Functional organization of the spinal cord, inWhittow GC (ed): Sturkies Avian Physiology (ed 5). SanDiego, CA, Academic Press, pp 71-82, 2000

9. Necker R: The avian ear and hearing, in Whittow GC (ed):Sturkies Avian Physiology (ed 5). San Diego, CA, Aca-demic Press, pp 21-38, 2000

10. Necker R: The somatosensory system, in Whittow GC (ed):Sturkies Avian Physiology (ed 5). San Diego, CA, Aca-demic Press, pp 57-70, 2000

11. Orosz SE, Bradshaw GA: Avian neuroanatomy revisited:from clinical principles to avian cognition. Vet Clin NorthAm Exot Anim Pract 10:775-802, 2007

12. ten Donkelaar HJ, Bangma GC: The cerebellum, in GansC, Ulinski P (eds): Biology of the Reptilian, vol. 17(neurology C). Chicago, IL,, University of Chicago Press,pp 496-586, 1992

13. Ulinski PS, Dacey DM, Sereno MI: Optic tectum, in Gans C,Ulinski P (eds): Biology of the Reptilian, vol. 17 (neurologyC). Chicago, IL, University of Chicago Press, pp 241-366, 1992

14. Wyneken J: Reptilian neurology: anatomy and function.Vet Clin North Am Exot Anim Pract 10:837-853, 2007

15. Jaggy A, Spiess B: Neurological examination of smallanimals, in Jaggy A (ed): Small Animal Neurology. Hann-over, Germany, Schlutersche, pp 1-37, 2010Hunt/Journal of Exotic Pet Medicine 24 (2015), pp 3451 5 1

Neurological Examination and Diagnostic Testing in Birds and ReptilesHistoryClinical ExaminationHow to Perform A Neurological ExaminationUseful TipsSummaryReferences

Neurological Examination and Diagnostic Testing in Birds and Reptiles

Documents

Transcript of Neurological Examination and Diagnostic Testing in Birds and Reptiles