Seizures

What is a seizure?

A seizure is a neurologic event in which disproportionate electrical brain activity results in abnormal behaviors, loss of consciousness, and/or convulsions.
Seizures are classified into two categories, partial and generalized. Partial seizures involve a specific region of the brain and cause strange behaviors such as circling, “fly-biting,” howling, or facial twitching. Generalized seizures are more common and are either convulsive (grand mal) or nonconvulsive (petit mal).

What are the clinical signs?

Signs of a generalized seizure (grand mal) include: stiffness and muscle rigidity, muscle trembling, loss of consciousness, excessive salivation, and uncontrolled urination or defecation. All, or only a few of these signs may occur during a grand mal seizure. Petit mal seizures are more difficult to describe and will manifest as if the patient is “zoning-out.”

There are 3 phases associated with a grand mal seizure. The aura, ictal period, and postictal period. The aura occurs prior to the actual seizure event and may last only a few minutes, or several hours. The symptoms of an aura may be very subtle and even go undetected, however some patients will exhibit pacing, vomiting, excessive salivation, vocalizing, hiding, or attention seeking. The ictal period refers to the actual seizure event and generally only lasts seconds to minutes. During the postictal period immediately following a seizure, the patient may appear disoriented, lethargic, be excessively thirsty or hungry, exhibit inappropriate urination or defecation, or even experience temporary blindness. While some patients experience very little postictal symptoms, others may have a more dramatic postictal period that can last 12 to 24 hours later.

What causes a seizure?

The most important step in treating a patient for seizures is to determine if in fact the patient is experiencing a true seizure. Because the range of manifestations for seizures is so broad, they can sometimes be difficult to describe. Also, cardiac and respiratory disease can result in passing-out that is easily confused with a seizure. If at all possible, video-taping the event may help your veterinarian determine what is happening with your pet.

Many different things can cause seizures including primary brain disease such as a tumor, stroke, inflammatory conditions, intoxications, and epilepsy. Secondary causes of seizures include low blood sugar, low calcium, and high red blood cell counts.The most common cause will vary according to the pet’s age – older patients with sudden onset of seizures are more likely to have a brain tumor, while young to middle-aged patients are more likely to have epilepsy.

Bloodwork will be done to check the pet’s glucose level, metabolic function, electrolytes,and cell counts,. In addition, blood pressure and EKG evaluation may be necessary if your veterinarian feels it is possible cardiac disease may be contributing to your patient’s symptoms.

Further workup for neurological disease can include advanced techniques such as cerebrospinal fluid sampling or imaging of the brain via MRI or CT.

How do you treat a seizure?

Treatment of seizures is dependent on the underlying cause. Initial treatment often includes injections of medications to stop the seizures – the first line drug is usually valium. In order for this drug to be most effective, an intravenous catheter is needed for immediate treatment of seizures while in-hospital. If the patient is continuing to seizure, it can be given injections of longer lasting anticonvulsants to help break the seizure cycle. In rare cases the pet may need to be anesthetized to stop the seizure activity.

While a patient is being worked-up for a cause of seizures, specific problems will need to be addressed as they are determined. For example, if the glucose level is low it will be supplemented. Often no specific cause is found without advanced imaging such as MRI or CT. If the MRI or CT reveals a brain tumor, you may consider consulting with a veterinary neurosurgeon to determine if surgery is in your pet’s best interest. In the case of epilepsy, all tests are normal, making this a diagnosis of exclusion. Some pets may require life-long oral anticonvulsant therapy such as phenobarbital and/or potassium bromide to control their seizures. The goal of anticonvulsant therapy is to decrease seizure frequency and severity, not necessarily eliminate seizures all together. As there are some side-effects to the drugs used for treatment, and their effectiveness may change over time, frequent follow-up and blood work monitoring with your veterinarian will be important for the life of your pet.

What should you do if your pet has a seizure?

If this is your pet’s first seizure, seek veterinary medical attention.
While minimal handling is best during a seizure, you do want to move pets away from areas they may fall from such as couches, beds, or near stairs.
Use blankets to cushion your pet to avoid head trauma if they are hitting their head on a hard surface.
Animals have no control over their jaw muscles during a seizure and therefore may involuntarily bite – keep your hands away from their mouths during a seizure.
Situations which require immediate veterinary medical attention include: seizures that last greater than 5 minutes (time the event for accuracy), repeated seizures or failed return to consciousness between seizures (clustering), or status epilepticus (a seizure that will not stop on its own).
Rarely patients will experience respiratory distress immediately following a seizure, if your pet is having difficulty breathing after a seizure they should be taken to a veterinary hospital right away.

Prognosis

The prognosis depends on what is causing the seizures and the pet’s response to medication. Younger animals more commonly have infections of the brain or idiopathic epilepsy. Older pets most commonly have a brain tumor called a meningioma. While medical management of seizures caused by brain tumors is often worthwhile, the long-term prognosis is guarded for these patients.

It is important to realize that the severity of the seizure does not always reflect the cause or prognosis. For example, a pet with a nonresectable brain tumor may have infrequent, mild seizures and a pet with epilepsy can have frequent, severe seizures.

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