Equine Neurology Flashcards
How do equine forebrain diseases commonly present?
Behaviour Seizure Blindness Altered Consciousness Head turn/pressing
What may be an iatrogenic cause of forebrain disease?
Intracarotid injection
What are the 3 main causes of neonatal seizure?
PAS, sepsis and trauma
Which neurological condition are arab foals predisposed to?
Juvenile idiopathic arab epilepsy
Starts before 1yo
What are the signs of vestibular Dz?
Head Tilt
Nystagmus
Ventral Strabismus
Ataxia
What is the most common cause of facial nerve paralysis in the horse?
Halters left on in field anaesthesia
Also: trauma/THO
What are the signs of facial nerve paralysis in the horse?
Dropped ear
Ptosis
Nostril Deviation
What problems can facial nerve paralysis lead to?
Exposure keratitis
Dysphagia
Poor Performance
What is the most common cause of horners in the horse?
extravascular injection of irritant substance (PBZ/buscopan)
What is Horners?
Interruption of SYMP supply to head (and neck)
What are the signs of horners?
Miosis, enophthalmos, ptosis, protruding
nictitating membrane.
Hyperaemic MMs
Sweating
What are the signs of cauda equine syndrome?
hypotonia/reflexia of tail/anus/perineal region
LMN weakness/paresis of pelvic limbs
What causes cauda equine syndrome?
Tauma: SacroCoccy #/luxation
Infection/inflammation: EHV1, Polyneuritis equi
Which herpesvirus may cause myoencephalopathy?
EHV-1
What are the signs of Herpes myoencephalopathy?
SUDDEN
Ataxia, paresis, incontinence
What causes the signs associated with equine herpes myoencephalopathy?
Vasculitis and thrombosis of arterioles in spinal cord
How is equine herpes myoencephalopathy diagnosed?
Location
Rule out other cause
CSF: xanthochromia & EHV-1 Ab
NPS: virus
Serum: High Ab titre
How is equine herpes myoencephalopathy managed?
Isolate
NURSE
NSAID, CS, Aspirin
Acyclovir
How can we diagnose spinal cord trauma in the horse?
Clinical exam & Hx plus Radiography!
CSF rules out other causes
How should spinal cord trauma be managed?
Aggressive Anti-inflm: CS, NSAID, DMSO
?Surgery
Box rest if standing, nursing if not
Which types of spinal injury carry a poor Px?
Luxation
Unstable #
Poor response in 1-2d
What is the most common cause of equine ataxia in the UK?
Cervical Vertebral Malformaiton (CVM)
What is Type I CVM?
Young Horse
Compression due to development
Dynamic Stenosis anywhere
What is Type II CVM?
Older Horse
OA of articular process
Static stenosis at c5-c6 OR c6-c7
How is CVM diagnosed?
Clinical exam and radiograph
If not diagnostic - myelography may be useful
How can you manage Type I CVM?
Dietary restriction
How can you manage Type II CVM?
IA Corticosteroids (US guided)
What is “Shivers” Dz?
Reflex hypertonia of flexor muscles of pelvic limbs
how does shivers initially present?
horse snatches up HL when being picked
What does shivers progress to?
HL being held in air in spastic state for some time
Which breeds of horse are predisposed to shivers?
Draft horses
Which type of diet has anecdotal support in the management of shivers?
High Fat, Low CHO
What is stringhalt?
Sudden involuntary exagerated flexion of 1/2 HLs during movement!
What causes the 2 types of stringhalt?
Plant: dandelion
Sporadic: unknown cause
How is sporadic stringhalt treated?
Myotenectomy of Lateral Digital Extensor
What are the most common causes of radial nerve injury in the horse?
External blow or recumbency
How does radial nerve damage present?
Inability to flex shoulder, extend limb or fix the elbow
What is “sweeny”?
“Shoulder Slip”
Atrophy of supra and infraspinatus muscles caused by Suprascapular nerve damage
How are peripheral nerve injuries treated?
Antiinflammtories
DMSO
Phsyio
What is EMND caused by?
low vitamin E
Which horses are predisposed to motor neurone disease? (EMND)
Stabled - no access to pasture for a long time
what are the signs of EMND?
weight loss
Muscle fasciculaiton
Prolonged recumbency
Ocular signs (brown pigment in retina)
How do you diagnose EMND?
Tail head muscle biopsy - measure vit E/Se levels
How is EMND treated?
VIt E supplement
What are the 3 common sources of botulism in horses?
Contamined silage
Water
Poultry litter and carcasses
What may be a rare form of c botulinum transmission in foals?
can grow in ingesta & pass through ulcers
How do C botulinum toxins cause clinical signs?
Block Ach release at NMJ –> Weakness
what are the clinical signs of botulism?
Abrupt progressive onset of flaccid paralysis: Symmetrical weakness, ataxia, dysphagia, low head
MAY be dyspnoeic, GI stasis
Which syndrome of foals (1-3m) is caused by c botulinum?
Shaker foal syndrome - inital trembling episodes
Why/when do horses die of botulism?
Resp muscle paralysis (takes 10d)
How is botulism diagnosed?
Identify spores/toxin in stomach content/faeces/feed
How is botulism treated?
GOLD STD: antitoxin
Normally: Penicillin (not procaine), IVFt and support
Where is C tetani (tetanus) found?
Soil - Gram + anaerobe
How does C tetani cause tetanus?
Neurotoxin inhibits presynaptic inhibitory neurones = continual contraction
Migrates along neurones to brainstem
What are the signs fo tetanus?
Elevated tail head Stiff gait Anxious Lock Jaw 3rd eyelid prolapse Recumbent/rigid
How is tetanus treated?
Antitoxin
ACP/Diazepam (relax)
Toxoid (away from antitoxin)
+ SUPPORT
+ Clean wound + metronidazole
How long may tetanus treatment need to be administered?
14d