Neurology: SA Neurological Exam, Equine Neurological Exam, Interactive

Question 1

What are the three components of the neurological consultation?

Answer 1

History

Observation- mentation, behaviour, posture, gait

Hands-on- physical, neuro examinations

Question 2

What are the different mentations?

Where does altered mentation indicate dysfunction?

Answer 2

Alert- normal response to environmental stimuli

Disorientated/confused- abnormal response to environment

Depressed/obtunded- inattentive, less responsive to environment

Stuporous- unconsciour but can be roused by painful stimuli

Comatose- unconscious, unresponsive

Altered mentation- forebrain or brainstem

Question 3

Where does alteration of behaviour indicate dysfunction?

What behaviours can change?

Answer 3

Forebrain

• Agression
• Compulsive walking/circling
• Loss of learnt behaviour
• Vocalisation
• Hemineglect syndrome- ignore half of environment

Question 4

Head tilt and Head and/or body turns are postural differences from neurological disease

How do they appear and where does it indicate disease?

Answer 4

Head tilt-
rotation on the medial plane of the head- one ear lower
Vestibular disease

Head and/or body turn-
Median plane of the head remains perpendicular to ground but nose to one side
Forebrain disease

Question 5

What is decerebrate/decerebellate rigidity?

Where do they indicate lesions?

Answer 5

Decerebrare rigidity-

• Extension of all limbs
• Release of inhibitory UMNS descending pathways on LMNS
• Lesion in rostral brainstem

Decerebellate rigidity-

• Hyperextension of TLs and opisthotonus
• Loss of inhibiton of stretch reflex mechanism of antigravity muscles
• Lesion in rostral cerebellum

Question 6

What is Schiff-Sherington?

What causes it?

Answer 6

Hyperextension of FLs, Paralysis of PLs

Interference with border cells- inhibitory neurons in cranial lumbar spinal cord that inhibit the FL extensor muscles

Lesion in thoracic of cranial lumbar spine

Question 7

How can gait be affected?

What are the terms used?

Answer 7

Ataxia- uncordinated gait- drunk

Paresis- weakness, reduced voluntary movement
ambulatory- falling but can walk
non-ambulatory- weight needs supporting

Paralysis- complete loss of voluntary movement

Question 8

What are the three causes of ataxia?

Answer 8

Spinal ataxia- usually subtle, due to decreases sensory information from limbs to CNS to know where they are

Vestibular ataxia- loss of orientation of the head with eyes, neck, trunk and limbs, causing loss of balance- leaning, falling, rolling
Towards side of lesion

Cerebellar ataxia- typically with inability to regulate rate, range or force of movement, dysmetria [overshooting]

Question 9

How can paresis be further described?

Answer 9

Tetra- all limbs

Para- pelvic limbs/hind limbs

Mono- 1 limb

Hemi- same side

Question 10

What are the 4 parts of a hands-on neurological examination?

Answer 10

Postural reactions

Spinal reflexes and muscle tone

Spinal pain

Cranial nerve examination

Question 11

What is postural testing?

What is it useful for?

What are the 3 postural reactions tested?

Answer 11

Testing awareness of prescise position and movement of the body

Useful to first identify a problem but not specific

• Paw position- turn paw so dorsal surface bears weight, see how quickly returned
• Hopping- support 3 limbs and hop laterally, hipsway/wheelbarrow
• Placing responses- pick up patient and bring limbs to edge of table so that dorsal surface touches surface

Question 12

What are spinal reflexes used for?

What are the two types of reflexes used in fore and hindlimbs?
How do they differ between FL and HL?

What is the cutaneous trunci reflex and what is it useful for?

Answer 12

Used to classify lesion as UMN or LMN- look at muscle bulk and tone, evaluate reflexes in FLs/HLs

Withdrawals- pinch digit, contraction of flexor muscles and limb should withdraw- Same for HL/FLs

Myotatic- strike muscle, contraction
FL- extensor carpi radialis, biceps, triceps
HL- patellar, cranial tibial, gastrocnemius

Cut trunci-pinch skin on back- contraction of muscle on both sides, usefil for T3-L3 lesions, brachial plexus lesions

Question 13

How is pain perception assessed?

What is the perineal reflex?

Answer 13

Pain perception-
Gentle squeeze of digit, look for behavioural response (head turning, vocalisation)

Perineal-
Stimulation of perineum with haemostat should cause contraction of anal sphincter

Question 14

How is spinal pain assessed?

Answer 14

Palpate all the spine, starting gently and progressively increasing the degree of pressure

Move neck in all directions- look for pain or resistance to move

Move tail and palpate lumbosacral region

Question 15

What are the different cranial nerve examinations that can be done?

For each test list the afferent nerve, intermediate location and efferent nerve

Answer 15

Palpebral reflex- V, brainstem, VII

Corneal reflex- V, brainstem, VII /VI

Physiological nystagmus- VII, brainstem, III/IV/VI

Menace response- II, forebrain/cerebellum/brainstem, VII

Nasal mucosal stim- V, forebrain/brainstem

PLR- II, brainstem, III

Gag reflex- IX and X, brainstem, IX and X

Question 16

Describe how to do a palpebral reflex test

Describe how to do a corneal reflex test

What is a physiological nystagmus?
What commonly causes a lost/reduced effect?

Answer 16

Palpebral- Touch medial/lateral canthus of the eye- blink

Lightly touch cornea- blink and eye retraction

Nystagmus- elicited by moving of head
Vestibular eye movement- lift head or put animal upside down
Look for evoked stabismus/nystagmus
Raised/lost most commonly due to raised intercranial pressure

Question 17

What are the input and output nerves for corneal and palpebral reflexes?

How can you use this to diagnose nerve dysfunction?

Answer 17

Input for both- trigeminal
Output-
Facial (VII)- blink- both
Abducens (VI)- globe retraction- corneal only

• If blink normally on both tests but doesn’t retract globe- abducens dysfunction
• If retracts globe normally but doesn’t blink for either trigeminal fine therefore facial dysfunction
• If neither tests result in reflex- likely trigeminal

Question 18

What is strabismus and Nystagmus?

How can they both be futher described?

Answer 18

Stabismus- abnormal position of the eyeball that the animal cannot overcome

Nystagmus- rhythmical, involuntary movements of the eyeball

Strabismus- resting or evoked
resting- CNs III, IV, VI dysfunction
evoked- positional, vestibular dysfunction

Nystagmus- physiological, jerk, pendular
physiological- normal in response to moving of head
jerk- slow and fast phase- vestibular dysfunction
pendular- equal oscillations- visual pathway dysfunction

Question 19

Describe horner’s syndrome in SA and Horses

Answer 19

Small animals-

• Miosis- pupil constriction
• Ptosis [drooping] of the upper eyelid with smaller palpebral fissure
• Protrusion 3rd eyelid
• Subtle enophthalmos- posterior displacment of eyeball
• Sometimes congestion of conjunctiva
• Warmth of skin, pinkness

Horse-

• mild miosis
• Ptosis of upper eyelid with smaller palpebral fissure
• Subtle protrusion of 3rd eyelid
• Decreased angle of eyelashes
• Excessive sweating in denervated area

Question 20

Describe how to do a nasal mucosa stimulation?

How do you do a menace response?
When can a menace response test not be done and why?

What is a pupillary light reflex?

How is a gag test done?

Answer 20

NMS- Touch nasal mucosa- head withdrawal

Menace- menacing gesture, cover other eye- blink
Not a reflex, learnt- takes 10-12 weeks in SA, 1-2 in horses

PLR- shine light into eye- constriction of pupil and other side (consensual)

Gag- open mouth or touch pharynx- contraction of pharynx

Question 21

What is wanted to be extracted from an equine neurological examination?

Answer 21

Is the horse neurologically normal

Where is the lesion

What is it

What can be done

Question 22

What are the limitations of equine neurological examinations?

Answer 22

Size

Behaviour/ danger

Recumbancy

Question 23

What should be assessed about a horse for a neurological exam from a distance?

Answer 23

Mentation- curious, paying attention/ dropped head, depressed, head pressing (forebrain)

Behaviour- aggression, compulsive walking/circling, loss of learnt behaviour, vocalisation

Posture- head tilt, head or body turn, wide-base stance

Question 24

How can the following cranial nerves be tested?:

• Olfactory
• Optic
• Trochlear
• Trigeminal
• Abducens

Answer 24

• CN I- difficult, polo mint test
• CN II- sight, menace, PLR (less obvious), very good at compensating with one eye for bad sight
• CN III- PLR, eye position with vestibular system
• CN IV- eye position with vestibular system
• CN V- mastication muscle atrophy, facial sensation- palpate and observe response
• CN VI- eye position with vestibular system

Question 25

How can dysfunction of CN VII be assessed?

Answer 25

Facial nerve- muscles of expression, sensory tongue/ear Muscles of facial expression- ears, eyes, blinking, dilation of nostrils, lips Assess facial symmetry Palpation can be useful

Question 26

How can CN VIII be assessed? What is the most common sign of dysfunction?

Answer 26

Head posture- dysfunction= tilt Induced eyeball movment Normal vestibular nystagmus (following train)- hold horses head and move side to side- should keep rhythmically moving Normal gait- dysfunction=ataxic Blindfold to eliminate eyes of vestibular Hearing- clap to see it ears move Dysfunction- ventral strabismus

Question 27

How can CN IX, X and XI be assessed? How can CN XII be assessed?

Answer 27

Let the horse eat some grass Sensory and motor to pharynx and larynx- Swallowing, can endoscopy Slap test- adduction of horses contralateral arytenoid cartilage XI motor to trapezius and cranial sternocephalicus XII- tongue size, tone and symmetry

Question 28

How is the neck, trunk, back, tail and anus assessed for a neurological exam?

Answer 28

* Observation and palpation of neck and back- atrophy, asmmetry, swelling * Range of movements of neck and back- use food, not if fracture suspected * Cervicofacial reflex- poke neck with pen, twitches lips- some do some don't- asymmetry * Testing back flexion- pen on withers and rub in midline- horses should dip then arch at lumbar area, pen in sternum * Cutaneous trunci reflex- gently touch flanks, horse should shake skin (flies), if not present move cranially * Perineal reflex, tail clamp, anal tone * Male external genitalia- penis not retracting * Rectal- assess lumbar, sacral vertabrae and bladder volume and tone

Question 29

What are the two broad causes of abnormal postures in horses?

Answer 29

Orthapaedic problem- broken leg Neurological- Loss of spatial awarness- doesn't correct Inability to move limb

Question 30

What are you looking for with gait of a horse in neuro exam? What is ataxia?

Answer 30

Looking for abnormalities in spontaneous and induced, posture and movement interpreted as ataxia and weakness Ataxia- subconscious proprioceptive defecits seen as irregular or unpredictable movement

Question 31

What are signs of ataxia in horses? How can signs be exaggerated? What are the 3 places of origin for ataxia?

Answer 31

Signs- poor coordination, swaying, limb moving excessively during swing phase Exaggerated by tight circles- pivoting, circumduction, serpentine, sudden stopping, backing Cerebellar, Vestibular or Spinal origin

Question 32

What signs are associated with ataxia in horses with the cerebellum, vestibular system and spinal?

Answer 32

Cerebellar- uncommon No weakness Hypermetric ataxia- accelerated range of movements Other signs- tremor, lack of menace Vestibular Loss of balance, hypometric ataxia, wide based Other signs- head tilt, nystagmus Spinal- Dysmetric ataxia +/- weakness

Question 33

How are equine ataxia defectits classified?

Answer 33

1. Subtle- just barely detected at normal gait, occur during backing, stopping, turning 2. Mild- detected at normal gate, exagerated by above movements 3. Moderate- prominent at normal gait, buckle with above movements 4. Severe- tripping and falling spontaneously at normal gait

Question 34

What creates weakness? What are the different types in horses? What can cause them?

Answer 34

Interruption to general somatic efferent (motor) pathways Extensor weakness- sinking/buckling, weak when pulling tail Flexor weakness- toe drag/delay, swinging movement Motor tract lesion- UMN- tail pull during movement Motor neuron- LMN- tail pull at rest

Question 35

Timmy a border terrier has the following symptoms: Obtundation- dull Right circling Abscent proprioception in left limbs- paw position Abscent menace response in left eye Reduced facial ensation in left side What is the location of the lesion?

Answer 35

**Right Forebrain** Circle towards lesion- right Proprioception contralateral Vision contralateral

Question 36

Max has the following symptoms: Ataxia with leaning to the right Head tilt to right No proprioceptive defectits Right positional strabismus Spontaneous nystagmus with fast left phase Where is the lesion?

Answer 36

**Right Peripheral Vestibular System** Signs of central vestibular disease- multiple cranial nerves affected not seen, proprioceptive defecits No cerebellar signs- truncal sway, tremors

Question 37

Milly has the following neurological signs: Mild leaning to the right Right head tilt Hypermetria left thoracic limb Clumsy hopping on left limb Where is the lesion?

Answer 37

**Left Cerebellum** Hypermetria- cerebellum Paradoxical head tilt- opposite side Proprioception on the same side- left

Question 38

Gingerboy- cat No menace bilaterally No PLRs bilaterally Normal proprioception Normal fundus exam and ERG- retina and fundus normal Where is the lesion?

Answer 38

**Optic chiasm or Bilateral CN2 (optic nerves)** If both PLR and menace affected- must be cranial to chiasm

Question 39

Buster Generalised ataxia with hypermetria Reduced proprioception in all limbs Owners has seen 3 seizures- difficult to train Where is the lesion?

Answer 39

**Multifocal** Cerbellar- hypometria, ataxia, can give reduced proprioception Seizures- forebrain, behaviour

Question 40

Bertie Absent proprioception in hindlimbs Normal in forelimbs Spinal reflexes unaffected Absent pain sensation in pelvic limbs Cutaneous trunci cut-off Localise the lesion

Answer 40

**T3-L3** Forelimbs not affected- must be caudal to T3 Reflexes intact L4-S3 normal

Question 41

Natasha- cat Tetraplegia- possible slight movement Proprioception absent/reduced in all limbs Normal spinal reflexes in pelvic limbs Reduced spinal reflexes in thoracic limbs- some pain Where is the lesion?

Answer 41

**C6-T2** All limbs- cranial to T3 At reflexes in forelimbs reduced- must be C6-T2

Question 42

Sam Monoparesis left forelimb Absent spinal reflexes in left FL Reduced sensation in left FL ipsilateral Horner's syndrome Where is the lesion?

Answer 42

**Left brachial plexus- neuropathy** Not C6-T2 should affect back leg on left side

Question 43

Charlie Flaccid tetraparesis/plegia Absent spinal reflexes in HL/FL Abnormal bark Where is the lesion?

Answer 43

**polyneuropathy- diffuse** Cannot be C6-T2- reflexes on HL reduced

Question 44

Minky Weakness Stiff, stilted gait Normal neural exam Where is the lesion?

Answer 44

**Myopathy- no neurological defecits**