Equine Seizures: Real Case

Question 1

How common is infectious encephalitis in the UK?

Answer 1

not common

• EHV spinal cord
• West nile virus (flavivirus spread by mosquitos throughout US)

Question 2

Which antipyschotic drug can lead to neuro signs similar to seizure?

Answer 2

Fluphenazine

Question 3

Potential physiological causes of equine collapse?

Answer 3

Sleep deprivation

- horses need REM sleep lying down

Question 4

What lesion may cause bilateral paresis of the thoracic limbs?

Answer 4

Brachial plexus (C6-T2)

Question 5

What pathogens can be detected on serology?

Answer 5

• EHV1 (differentiate from vax - PCR on NP swabs or buffy coat of blood)
• lyme dz (associated with ticks and deer - SW, N, hard to dx as often sero +)
• louping ill (more common sheep and goats, occasionally seen SW)
• sarcocystis neurona
• toxoplasmosis
• neosporosis

Question 6

How many cervical vertebrae do most mammals have?

Answer 6

7 (manitees and sloths have 6)

Question 7

Most common cause of seizures in horses?

Answer 7

1* Idiopathic

Question 8

Tx seizures in horses?

Answer 8

• phenobarb
• diazepam/midazolam SID/CRI
• alfalfa (high calcium) hay
• calcium carbonate
  +- TMPS BID in case of bacterial meningitis? afe long term, oral, ok for pregnancy
• prednisolone?? (not sure why)

Question 9

What may be added into tx if horse is pregnanct to v risk of abortion?

Answer 9

• progesterone analogue (regumate altrenogest)

Question 10

Define focal seizures

Answer 10

• repeaable, focal eg. localised muscle fasciculations

Question 11

Define generalised seziures

Answer 11

• generalised, progress from facial -> multi muscle groups +- conciousness and collapse

Question 12

Define status epilepticus

Answer 12

• severe tonic clonic muscle spasm + collapse
• unconcious
• dont last long

Question 13

What benign condition manifests as seizures?

Answer 13

Benign epilepsy of Arab foals

• cluster seziures starting @2-3 mo
• grow out by 1 yr
• metabolism and PE NAD
• = Lavender foal syndrome associated with hair coat colour change

Question 14

Tx benign epilepsy of arab foals

Answer 14

Phenobarbitone

Question 15

Causes of 2* seizures

Answer 15

> metabolic 
- hepatic encephalopathy usually depressive rather than seizure inducing 
> electrolyte imbalance
- v Ca
- v Mg
- v Cl 
> neoplastic 
- rare
> space occupying lesions
- strangles lesion in brain 
- cholesteatoma choroid plexus ventricles (cholesterol granuloma) -> 2* hydrocephalus d/t v CSF outflow 
> iatrogenic
> air embolism
> intra-carotid injection 
> post-myelography 
- avoid metrizamine contrast agent, use IOHEXOL instead and tilt head during injection 
- premed with dexamethosone to v sterile inflam responsee to drug