seizures SA

History

·    How long do episodes last? Any change?

·    How frequent? Any change in frequency?

·    Any known trigger?

·    Are they normal between episodes? – abnormal between episodes = structural cause

·    Any other neurological signs?

·    Do they have a video?

·    Are they vaccinated? – rabies?

Signalment

·    <6m old – hepatic encephalopathy (PSS), juvenile onset hypoglycaemia, congenital malformations (hydrocephalus)

·    6m-1yr – idiopathic epilepsy most likely

·    >6yr – hypogylcaemia, neoplasia

Approach and management

·    If seizuring - anti-convulsants

o  Phenobarbitone – licensed in dogs and cats

§ Takes 2w to reach desired level in blood

§ Side effects – sedation, PUPD, polyphagia, incr. liver enzymes

o  Imepitoin – licensed in dogs for idiopathic epilepsy

§ Side effects: sedation, PUPD, polyphagia

o  Potassium bromide – licensed for secondary additional therapy

§ Takes 2m to reach desired level in blood

§ Side effects: sedation, PUPD, polyphagia

o  Rectal diazepam

Examinations:

·    Pyrexia? Systemically unwell?

·    Metabolic signs, e.g. jaundice

·    Neurological exam – vestibular signs (head tilt)? Non-forebrain signs

o  Seizures are usually forebrain lesions

Investigating cause:

·    Rule out metabolic causes – biochemistry

o  Hypoglycaemia, diabetes, hepatic encephalopathy, thiamine deficiency

o  If low glucose – give glucose

·    Rule out low oxygen – EPOC, supplement O2 if needed

·    Rule out structural causes – MRI/CT, CSF tap

o  Signs of increased ICP – swelling of optic disk, fundus haemorrhage

·    If all other causes ruled out = idiopathic

Treat underlying cause:

·    Low glucose – give glucose

o  Insulinoma – preds, nutritional management

o  Diabetes – get under control with insulin

o  Xylitol toxicity – anti-oxidants, glucose supplementation CRI (prevent insulin spikes)

·    Hepatic encephalopathy – low protein diet to decrease ammonia, treat kidney/liver disease

·    Thiamine deficiency – supplement vit B1, change diet from raw fish

·    Stroke – clopridogrel/aspirin to reduce platelet aggregation, vit K for rat poison

·    Increased ICP due to inflammation – corticosteroids

Causes

·    Low glucose: insulinoma, diabetes, xylitol toxicity

·    Decreased oxygen to brain: hypovolaemic, obstructive, cardiogenic, distributive shock

·    Decreased blood flow to brain: cerebrovascular accident/stroke

o  Pro-thrombotic state – DIC, HCM, IMHA, PLN, cushings

o  Aneurysm

o  Pro-coagulatory disease – rat poison, vWF, coagulopathy

·    Increased ICP: inflammation, hydrocephalus, trauma, drinking too much water, neoplasia

·    Inflammatory

o  Infectious: FIP, rabies, protozoa (toxoplasma, Neospora)

o  Non-infectious: MUO

·    Other metabolic causes:

o  Hepatic encephalopathy – acute liver disease, kidney disease, congenital/acquired PSS

o  Thiamine deficiency – raw fish diet

·    Metabolic – rule out with biochemistry

·    Structural – abnormal in between seizures, MRI/CT looking for neoplasia, bleed

·    Idiopathic – normal in between seizures, rule out other causes

·    Status epilepticus – uncontrolled seizures