Seizure disorder, or epilepsy, is a central nervous system disorder that causes periodic seizures unrelated to progressive brain disease. It is one of the most common neurologic problems in dogs.
The three forms of epilepsy include primary epilepsy (also known as idiopathic epilepsy), juvenile epilepsy, and acquired epilepsy. Dogs with epilepsy appear normal between seizure episodes. Some dogs become anxious just before a seizure and may either hide from you or seek your attention. The seizures usually affect the whole body, last one or two minutes, and cause loss of consciousness.
During a seizure, the dog typically stiffens, chomps his jaw up and down, salivates, urinates, defecates, and makes a paddling motion with all four limbs. Some dogs may experience mild, generalized seizures in which they don't lose consciousness but have uncontrollable muscle rigidity or trembling. After a seizure, the dog may be confused and temporarily blind. Seizures usually occur when a dog is resting or asleep during the night or early in the morning.
Risk factors and detection
Primary epilepsy is common in dogs. It can affect any dog, but certain breeds often inherit primary epilepsy, including beagles, Belgian Tervurens, Border collies, boxers, cocker spaniels, collies, dachshunds, German shepherds, golden retrievers, Irish setters, keeshonds, Labrador retrievers, poodles, Saint Bernards, Shetland sheepdogs, Siberian huskies, English springer spaniels, Welsh corgis, and wire fox terriers. Primary epilepsy occurs most frequently in dogs between 6 months and 5 years old, and male dogs are at higher risk.
Juvenile epilepsy develops in very young puppies, usually 8 to 12 weeks old. This condition, which affects such breeds as cocker spaniels, can be difficult to control, but pups may grow out of it by 4 to 6 months of age.
Acquired epilepsy affects dogs of any age and breed. It stems from brain injury caused by trauma or infection, such as distemper. Damaged nervous tissue serves as a starting point for the seizures. However, it might take six months to three years after the original injury before a seizure occurs. In most cases, the original injury is never identified.
Signs of epilepsy include:
- seizures
- urine and feces spread out or smeared on the floor
- urine and feces on your dog's fur
- confusion or behavioral changes
- uncontrollable muscle rigidity or trembling
- a state of continual seizure activity, known as status epilepticus. Status epilepticus is a life-threatening emergency. Take your dog to the veterinarian immediately so the doctor can stop the seizure activity.
If you notice any of these signs and think your dog may have experienced a seizure, take him to your veterinarian. Your dog's doctor will ask about the nature of the seizures, your pet's family history of seizures, and if the dog was exposed to poisons or infectious agents. He or she will perform a complete physical examination and may use blood tests, urine tests, X-rays, and ultrasound to rule out other causes of seizures, including low blood sugar levels, low blood calcium levels, poisoning, liver disease, brain tumors, and infectious disease. Your veterinarian also may refer you to a veterinary specialist for advanced diagnostic techniques, such as cerebrospinal fluid analysis, computed tomography (CT) scan, or magnetic resonance imaging (MRI), though this is rarely necessary with primary epilepsy.
Prevention and treatment
If the veterinarian diagnoses primary epilepsy in your dog, neuter or spay the dog to prevent passing epilepsy to offspring. Avoiding head trauma or serious infection will reduce your dog's risk for acquired epilepsy.
Don't allow dogs with epilepsy to swim because they can experience seizures in the water and drown. Another precaution: Place your dog in a large kennel each night to sleep. If he experiences a seizure during the night, the kennel will protect him from injury (such as falling down stairs, falling off furniture, or banging against a hard object). Keeping him confined also will make morning cleanup easier.
If you witness your dog having a seizure, make sure that he is away from stairs or any other hazards. But don't put your fingers in his mouth—he won't swallow his tongue, but he might bite you inadvertently.
If your dog develops epilepsy, the veterinarian will ask you to record the seizures and any event or condition that seems to trigger them, such as thunderstorms or excitement. This journal will help your veterinarian decide if treatment is necessary. Not all dogs with epilepsy require treatment. The medications for epilepsy don't completely eliminate seizures, and they can cause side effects and complications. If the seizures are mild and infrequent—less than one every five to six weeks—then the benefits of treatment don't outweigh the risks.
Anticonvulsant medication can help dogs who experience frequent seizures, cluster seizures (many seizures in a short period), and status epilepticus. However, once you administer anticonvulsant medication, your dog becomes dependent on it. Abruptly stopping the medication may trigger seizures.
Phenobarbital is the preferred anticonvulsant. If your veterinarian prescribes this drug, he or she will periodically test blood levels of the medication and adjust the dose as needed. Also, the doctor will run blood tests once or twice a year to make sure the drug isn't damaging your dog's liver. Phenobarbital increases thirst and appetite and can contribute to obesity. Your veterinarian may use the anticonvulsant potassium bromide alone or in combination with phenobarbital to maximize seizure control
The drug diazepam can interrupt seizure activity in dogs experiencing status epilepticus. Diazepam isn't used for routine seizure control in dogs because its effect is short-lived, requiring frequent doses.
Primidone, valproic acid, clonazepam, and clorazepate are anticonvulsant medications that treat epileptic dogs who don't respond to phenobarbital alone. However, these drugs cause a lot of adverse side effects, they're expensive, and their effectiveness is unproven.
Prognosis
Most dogs with epilepsy lead good quality lives. Dogs who experience frequent seizures, cluster seizures, and status epilepticus and those who don't respond to drug treatment have a guarded prognosis because they're more likely to die from status epilepticus.
