FieldDxCanine / Feline EpilepsyClinical signs, differential diagnosis, treatment and prevention in dogs and cats.
Overview
Recurrent seizures from abnormal brain electrical activity. Idiopathic (presumed genetic) in many young dogs with no other identifiable cause; secondary to structural brain disease, metabolic disease, or toxin exposure in other cases.
Clinical signs
- Grand Mal (Major): Sudden loss of consciousness, tonic-clonic convulsions (rigidity, paddling, champing of jaws, foaming, involuntary urination/defecation) .
- Followed by a post-ictal phase of flaccidity, depression, and blindness.
- Petit Mal (Minor): Brief absence seizures with blinking, head nodding, or mild muscle jerks.
Predisposing factors
- Idiopathic (genetic predisposition, highly common in breeds like Cocker Spaniels and German Shepherds) or symptomatic (secondary to brain tumor, head trauma, meningitis, or metabolic toxicosis) .
Look-alikes to rule out
Treatment
- Status Epilepticus: Administer diazepam (0.1–0.4 mg/kg slowly IV) 5 or a constant-rate infusion of diazepam (0.5–1 mg/kg/hr).
- Alternatively, use propofol as a constant-rate infusion (0.1–0.6 mg/kg/min).
- Maintenance: Administer phenobarbital (2–4 mg/kg/day PO divided bid).
- Monitor serum therapeutic levels (15–45 mcg/mL) after 2 weeks.
- Never stop phenobarbital abruptly to avoid precipitating withdrawal seizures.
Drugs mentioned: Phenobarbital Propofol Diazepam
Prevention
Genetic screening of breeding lines; avoid exposing animals to known neurotoxins or extreme environmental stress; perform routine diagnostic imaging for symptomatic cases.
Source
Textbook of Clinical Veterinary Medicine by Amalendu Chakrabarti (Page 492 / Passage 492); The Merck Veterinary Manual 11th Edition (Passages 47, 266, 387–389).
MSD Veterinary Manual — Seizure Disorders in Small Animals (accessed 2026-08-11)
Condensed and attributed, never reproduced whole. Open the full entry in the app.