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CLINICAL TECHNIQUE
NEUROLOGICAL EXAMINATION AND DIAGNOSTICTESTING IN BIRDS AND
REPTILESCraig Hunt, BVetMed, CertSAM, DZooMed, MRCVS
gin.tengalp
sis
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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
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,(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
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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
3 8 Hunt/Journal of Exotic Pet Medicine 24 (2015), pp 3451
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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
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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.
4 0 Hunt/Journal of Exotic Pet Medicine 24 (2015), pp 3451
-
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.
4 6 Hunt/Journal of Exotic Pet Medicine 24 (2015), pp 3451
-
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.
nt/Journal of Exotic Pet Medicine 24 (2015), pp 3451
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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
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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
nt/Journal of Exotic Pet Medicine 24 (2015), pp 3451
-
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