The neurological horse with abnormal mentation Flashcards
Describe depressed mentation
animal is awake but not alert to surroundings, not interested in normal stimuli
Describe obtunded mentation
animal is dull and slow to respond but will respond appropriately
Describe stuporous mentation
animal is unresponsive to normal stimuli but can be aroused with strong stimuli
Describe comatose mentation
state of unconsciousness in which the animal cannot be aroused, even with noxious stimuli
List the general signs of forebrain disease
obtundation
head-pressing
teeth grinding
hyperstesia
blindness
seizures
circling
head turn
ataxia
4 neurological issues causing abnormal mentation
Viral encephalitides
head trauma
hepatic encephalopathy
leuko-encephalomalacia
4 viral encephalitides that cause abnormal mentation
Eastern/Western/Venezuelan equine encephalitis
west Nile virus
Borna
Rabies
Describe hepatic encephalopathy
accumulation of ammonia in the blood due to congenital shunts or dysfunctional liver
the ammonia reaches the brain and astrocytes remove it and convert it to glutamine
Describe the effect glutamine has on the brain
increases in glutamine lead to astrocyte swelling (oedema) and GABA neuron inhibition
List the clinical signs of hepatic encephalopathy
depression
obtundation
head pressing
compulsive walking
ataxia
seizures
Describe how to diagnose hepatic encephalopathy
liver enzyme elevation
hyperammonaemia, low BUN and prolonged clotting times in severe disease
Describe how to treat hepatic encephalopathy
treat liver disease
IVFT + dextrose, oral lactulose and/or mineral oil (absorps ammonia in GIT), xylazine/detomidine in severe cases
change diet - low protein and high carbohydrates
List the clinical signs of head trauma in horses
epistaxis
haemoptysis
ear bleeding
retropharyngeal swelling
blindness
cranial nerve deficits
irregular breathing
anisocoria
obtundation/comatose
Describe how to treat head traumas
establish airway
obtain vascular access
clean and dress wounds
antibiotics
padded helmet to prevent further trauma
control temperature
hypertonic saline + mannitol to control ICP
oxygen
antioxidants
NSAIDs
steroids
Describe seizures
abnoraml, synchronous electricl discharges in the neurons of the forebrain that lead to spontaneous paroxysmal, involuntary movements
Describe the diagnostic plan in a case of seizures
rule out structural aetiology
Good physical exam
full haem and biochem
CSF tap
Skull X-rays, guttural pouch endoscopy
Describe how to treat seizures during the acute phase
midazolam
diazepam
phenobarbital
Describe the safety considerations that need to be made when handling horse that seizures
can collapse at any time
handled by someone experienced on long rope
needs large stable with thick bedding
don’t ride until 6 months after withdrawal of medication
List the clinical signs of EEE/WEE/VE
high fever
forebrain disease signs
head-tilt
muscle tremors
recumbency
what type of hosts are humans and horses for WEE and EEE
dead end hosts
what type of hosts are humans and horses for VE
amplification hosts
are EEE/WEE/VE notifiable?
yes
how do we diagnose EEE/WEE/VE
clinical signs + signalment
serological IgM tests
CSF analysis (neutrophilic inflammation with high protein)
prognosis for EEE/WEE/VE
BAD
