Seizures, part 1: the questions to ask

Clients often panic when they think their pet is having a seizure and can skip over vital information.

Often, what an owner describes as a “fit” may actually be syncope, collapse from anaphylaxis or internal haemorrhage (for example, neoplasia), a vestibular event or a behavioural condition.

True seizures

True seizures can be divided into two groups:

• Generalised (grand mal) seizures, which involve both cerebral hemispheres and result in loss of consciousness, incontinence and muscle activity.
• Focal/partial (petit mal) seizures, which originate from a focal region in the brain. These can also result in alterations in consciousness, but more typically only manifest in the form of repetitive twitching or limb movement.

Once you have established the owner is likely describing a true seizure, there are many important questions to ask to narrow down your differential diagnoses and treatment options.

The important questions

So, as part of a thorough history, always ask:

Was the pet conscious during the episode?

This will help to determine whether the seizure was generalised or focal.

How long did the episode last?

Status epilepticus is when a continuous seizure lasts more than five minutes or when the patient has not recovered fully before another seizure occurs. This can result in severe secondary brain injury.

How many episodes has the pet had in the past?

Epilepsy is the condition of recurrent seizures. This can be further classified as primary and symptomatic epilepsy, with symptomatic being secondary to an underlying cause (such as head trauma or a brain tumour).

How close together were the episodes?

• Cluster seizures are when an animal has more than two or three episodes within a 24-hour period.
• If a patient presents first time with a cluster, this carries a poorer prognosis in dogs, but has no influence in cats.
• Clusters are generally an indication for commencing long-term management.

How was the pet before and after the episode?

• Seizures often come with predicting (pre-ictal) and recovery (post-ictal) events.
• In the pre-ictal phase, the patient may act strangely (for example, agitated or clingy) and may vomit.
• Alterations in consciousness prior to a seizure usually indicate an intracranial cause.
• The post-ictal phase can last anywhere between minutes and days, and animals are usually disorientated and/or lethargic. They may also appear blind.

Has the pet demonstrated any other strange activity recently?

• For example, if an animal has also been circling to one side, you can start to predict the location of the lesion.
• Cats more commonly present with partial seizures compared to generalised – this is seen as stereotypic behaviours and bursts of activity.

Has the pet been exposed to any toxins or chemicals?

Seizures caused by toxins (such as snail bait) generally do not stop and start, but are continuous.

In the next part of this series, we will look at differential diagnoses for seizures and highlight the differences between dogs and cats.