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Seizures: Causes and Diagnosis

Seizures, also called convulsions or fits, are sudden neurological events that cause change in consciousness and involuntary movements. Duration can last from a few seconds to several minutes.

They are classifies as generalized (grand mal) involving all the body, and partial (petit mal) involving just one area of the body.


There are three categories of cause

- structural brain disorders (such as tumours)

- Metabolic problems and toxins affecting brain function

- Seizures where an underlying disorder cannot be identified (idiopathic epilepsy)

Structural brain disorders can include congenital birth defects such as hydrocephalus, brain tumours, traumatic brain injury, vascular strokes, degenerative changes and infections.

Metabolic disorders include severe liver and kidney disease, electrolyte imbalance (sodium or calcium), low blood sugar, high blood pressure and various poisons (such as organophosphate insecticides)

Age, breed, history, description of seizure (video of seizures at home are very useful) and clinical findings are important.

Clinical Signs

During a generalized seizure the animal is unconscious and unresponsive. They may fall down. The limbs are often rigidly stretched or jerking (paddling) as if running. There may be chewing and hypersalivation, and the dog may urinate or defecate.

During a partial seizure, jerking or twitching of the head or a single limb may occur. There may also be confusion, excessive barking or unprovoked aggression.

Some animals have abnormal behaviour before  seizures (preictal) including restlessness, nervousness and attention seeking.

Some also have abnormal behaviour afterwards (postictal) including restlessness, panting and hyperactivity. Some may appear confused or blind. This period can last from several minutes to 24 hours.

Animals with brain diseases and metabolic or toxic problems will often have other clinical signs such as vomiting, diarrhoea, weakness and weight loss. Young animals may be stunted in size.

Diagnostic tests

Animals should have full physical and neurological examinations, routine blood and urine tests and possibly radiographs.

However identification of specific brain disorders requires more specialized imaging such as MRI. At Acorn we can rapidly arrange a CT or MRI scan if required.

Collection of cerebrospinal fluid for examination is also sometimes useful.


If an underlying cause is identified then specific treatment can be started for that disorder.

Symptomatic treatment to control the seizures may also be initiated depending on their frequency, duration or severity. As a general rule of thumb treatment is started if seizures occur more frequently than once a month, if multiple seizures occur within a 24 hour period, or if the underlying disease cannot be cured.

Follow-up and Prognosis

This is highly dependant on the underlying cause. Prognosis is good if it can be resolved and guarded if it cannot be treated.

It is recommended that the owner keep a diary of timing and frequency of seizures, which will often occur in clusters, and this may well aid in further follow-up.

Prognosis for idiopathic epilepsy is normally good as many of these seizures can be controlled.