Cerebral, brainstem, and cerebellar disease in the horse

What are TWO causes of extracranial seizures?

Intracarotid injection

Procaine reaction (PPG venous injection)

T/F If you give PPG IV, then it will cause the horse to have a violent seizure

True

What are some metabolic causes of extracranial seizure?

◦ Hypo/hyperglycemia

◦ Electrolyte disturbances

◦ Hepatic encephalopathy

◦ Renal disease (uremic encephalopathy)

What is the most common electrolyte of

What is something that you should do on a horse that has had a seizure?

bloodwork (it can help to rule out alot of the metabolic issue)

What is a common cause of intracranial seizures in horses?

Structural or inflammatory brain disease

in neontal foals what are TWO things that can cause seizures in foals?

◦ Hypoxic ischemic encephalopathy/maladjustment

syndrome

◦ Sepsis/Meningitis

What horse breed is known for juvenile epilepsy (idiopathic epilepsy)?

Arabian horses of Egyptian

lineage

An arabian foal that is 2 months old has had some episodes of seizures and has started to walk into the walls. What disease do they have and can they grow out if it?

Jevenile epilepsy

yes (2 years)

What is the first step in seizure treatment? What are the drugs you can use? (3)

STOP SEIZURE: Diazepam, Phenobarbitol, Midazolam

What are FOUR drugs that you can use fro maintenance therapy?

Phenytoin, Phenobarbital, Potassium bromide, Levotiracetam

What part of DAMNITV is Cerebellar abiotrophy?

Anomalous

Horses with Cerebellar abiotrophy are ____ at birth but progress starts ___ ___ to ___ ___

normal, 6 weeks-4 months

What are some clinical signs of Cerebellar abiotrophy?

Hypermetria, cerebellar ataxia, intention tremors, lack of menace response, truncal sway

What is the pathogenesis of cerebellar abiotrophy, specifically in arabian horses?

Autosomal recessive mutation at transcription factor binding site for MUTYH

Where can you do genetic testing for cerebellar abiotrophy?

UC Davis genetic testing laboratory

What will you see on histopathology when a horses has cerebellar abiotrophy?

degenerative purkinje cells

What are the most common viral encephalitis in horses?

West Nile Virus (WNV), Eastern Equine Encephalitis Virus

(EEE)

What are the clinical signs of WNV?

•Muscle fasiculations/tremors

•Ataxia (mild)

•Mentation changes: depressed to obtunded

•Cranial nerve abnormalities

What is the vector of WNV?

mosquito

What is the vector of EEE?

birds

T/F Humans and horses are dead end host of WNV

true

What is the fatality rate of WNV?

30 %

What is the fatality rate of EEE?

>90% mortality rate

What are the clinical signs of Eastern Equine Encephalitis?

Fever (inconsistent, only at onset)

•Ataxia

•Mentation changes (depressed, obtunded,

somnolence most common)

•Cranial nerve abnormalities

• Difficulty/inability to swallow

• Vestibular signs

How do you treat WNV/EEE?

supportive care

What are THREE Antiinflammatory drugs that can be used?

◦ Steroids (Dexamethasone, methylprednisolone)

◦ NSAIDS (Flunixin meglumine)

◦ DMSO (Dimethyl sulfoxide)

What vitamin can be supplemented to help with neurologic up keep ?

Vitamin E

What are the serology test looking for when diagnosing WNV/EEE/WEE?

IgM Capture ELISA (specific for virus)

When you do a CSF tap for WNV, what cells would you expect to see?

mononuclear

When you do a CSF tap for EEE, what cells would you expect to see?

Neutrophilic or lymphocytic

What is the first antibody to appear in response to an infection?

IgM

How do you prevent WNV/EEE/WEE?

VACCINATION

What is the vaccination guideline of WNV,EEE,WEE based on AEEP vaccination guideline?

6 month interval in constant mosquito area (like alabama)

T/F WNV/EEE/WEE vaccines are killed and very effective and that is why we should use them

True

With Rabies the onset of signs is ____, ___, and ___ dependent

Strain, dose and bite-site dependent

What is the incubation period for rabies?

2-9 weeks

What are the clinical signs of rabies in horses?

• Anorexia, fever, depression

• Colic

• Lameness

• Any neurological sign

What is the only way that you can have a definative diagnosis of rabies?

Fluorescent Antibody (FA) test on brain

T/F Rabies is a core vaccine for horses in the AAEP

True

When should you first vaccinate a foal and when do they get their booster?

at 6 months, booster 4-6 weeks later

Most states require administration by a ____ and most state (do/do not) legally require it

veterinarian, do not

What are some other names for Leukoencephalomalacia?

"Moldy corn disease" "Hole in the head disease"

How long does a horse have to eat moldy corn to get Leukoencephalomalacia?

> 3 wks

What is the specific toxin that causes Leukoencephalomalacia?

Fusarium moniliforme (B1 toxin)

How do you diagnose Leukoencephalomalacia?

Test for fumonisin B1 in feed

You send a horse to necropsy that you suspect died from Leukoencephalomalacia, what would you expect to see on necropsy?

liquefactive necrosis

What are the clinical signs of liquefactive necrosis?

◦ Cerebral neurologic: Somnolence, Mania, seizures, mentation changes

◦ Liver failure: Hepatoencephalopathy, Icterus

What is the most common cause of trauma in horses?

Classic "Flipping over injury"- Basisphenoid fracture

What is the most common way to diagnose trauma?

Imaging- CT or radiographs

What can a CSF show if trauma is indicated?

hemorrhage, inflammation or previous hemorrhage

What can be used to treat trauma in horses?

Antiinflammatory (NSAIDS, DMSO)

T/F Steroid are contraindicated for trauma cases in horses

True

What can be used for anti edema in trauma cases?

Mannitol

Furosemide?

3% Hypertonic saline

What drug should only be used if there is no hemorrhage?

mannitol