Neurological exam of the horse and neuro diseases Flashcards
What does hypermetria, intetion tremors and weakness point towards
Cerebellar lesion
What is the first question to ask during neurological exam
Are there are cranial nerve signs present
What virus can have neurological and respiratory presentations
Equine herpes virus
What localisation would blindness, dementia, seizure, mild ataxia point towards
forebrain
What location would gait CN signs, gait deficits, tetraparesis and altered consciousness point towards
Brainstem
If we see tail/bladder paralysis, perineal hyperalgesia what localistion of lesion does this point towards
Sacral
What behavioural abnormalities might we see with forebrain disease
Yawning
Wandering
Psychosis
Circling
Head pressing
Seizures
What are some possible causes of forebrain dysfunction
Trauma to head
Hyponatraemia, hypoglycaemia
Hepatic encephalopathy hyperammoniaemia
Toxicity
Space occupying lesions
Intracarotd drug administration
How quickly will a horse react to an intra carotid drug injection
Immediately off the needle
How can we classify seizures
Either generalised or focal
Then focal split into simple focal or complex focal +/- secondary generalisation
Difference between simple focal and complex focal seizures
Complex focal has impaired consciousness
Signs of a generalised seizure
Loss of consciousness
Tonic clonic contraction
Limb paddling
Loss of continenance
Jaw clamping
WHen might strabismus be normal
NEwborn foals
What CN dysfunction causes a ventrolateral strabismus
CN III oculomotor nerve
What CN dysfunction causes a medial strabismus
CN VI
What CN dysfunction causes a dorsal strabismus
CN IV
Pathway for pupillary light response
Photoreceptors –> optic enrve –> optic chiasm with 90% decussation –> contralateral optic tract –> visual cortex + some to pretectal nuclei to prasymp CN III nuclei for pupil constriction (some crossing back here hence consensual response)
Which nerve is responsible for pupil constriction in PLR
CN III
Difference between dazzle response and PLR
Dazzle response uses a higher level of response with rostral colliculi but sitll subcortical
ONly gone in very bad disease
What do we expect to see with the swinging light test
Both pupils constrict with more constriction when light moved to contralateral eye
PAlpebral reflex
Touch medial canthus; stimulates CNV trigeminal sensory branch
Get blink response via Facial nerve motor
What is important to remember about the menace response
IT is learned; absent for a few days
What might a slow, abnormal menace indicate
cerebellar disease since cerebellum has a role in coordination and smoothing the menace response
What nerve controls head position and if there is a lesion which way does it go
VEstibulocochlear
Fall towards side of lesion
What are classic signs of facial nerve paralysis
Ear droop on that side
Eyelid droop
Muzzle twisted towards normal side
What is the cervicofacial reflex
Tap neck at C1-C2 and look for grimace from the corner of the mouth; tests C1/C2 nd CNVII
What would an animal with proprioceptive defects look like when walked; esp with head raised to move line of sight
Excessively floaty forelimbs
What disease would be shown up when horse blindfolded and asked to move
Proprioceptive defects with vestibular disease
What does it mean about deficits if proprioception is abnormal at rest vs when moving
If abnormal at rest = conscious deficits
If when moving = unconscious proprioceptiv deficits
Grades 0-5 ataxia
0 = normal
1 = mild neuro deficits only under special circumstances e.g walking in circles
2 = mild neuro deficits at all times/giats
3 = moderate deficits at all times
4 = severe deficits with tendency to buckle, stumble, trip, fall
5 = recumbent
Basic signs with UMN lesion
Paresis
Hyperreflexia
Basic signs with LMN lesion
Paralysis/paresis
Neurogenic muscle atrophy
Loss of reflexes
What would we see with gait at C-C5 lesion
UMN signs in fore and hindlimbs with hindlimbs looking worse
Wha would we see with C6-T2 lesion
LMN signs in forelimbs
UMN signs in hindlimbs
So forelimbs look ‘worse’
What would we see with T3-L3 lesion
Normal forelimbs, UMN signs to hind lims
What would we see with L4-S1 lesoni
Normal forelimbs
LMN signs to hindlimbs
What would we see with sacral/caudal lesions
Normal forelimbs
Normal or LMN signs in hing limbs
Cauda eqiune sign e.g bladder issues