Seizures are the result of the abnormal activity of neurons in the brain and are relatively common in veterinary patients. Seizure events are usually brief (1-2 minutes) and self-limiting, but some animals may have prolonged activity (status epilepticus; seizures lasting more than 5 minutes) or runs of seizures over a less than 24 hour period (cluster seizures). Status epilepticus and cluster seizures are particularly concerning and can result in death as they lead to increased body temperature and metabolic changes within the body.
Classically, seizures are manifest by the loss of consciousness, involuntary convulsions, salivation, urination, and increased heart rate. However, some animals with seizures will not exhibit all of the classical clinical signs, making seizures sometimes challenging to recognize and diagnose.
There is a variety of causes for seizures in animals. Veterinarians often divide the causes of seizure activity into those that arise from physical problems within the brain (for example tumors or brain inflammation), metabolic issues outside the brain that make seizures more likely or idiopathic causes (genetic problems with chemicals in the brain).
Physical examination, neurological examination, blood work, MRI, and spinal fluid analysis are often used to discern the cause of seizure activity. While reducing the frequency of seizures is very important, ignoring potential underlying causes for seizures is not recommended.
Management of seizures will not necessarily eliminate all seizure activity, but it should decrease the frequency and severity of the events. Traditionally, Phenobarbital and potassium bromide have been used to control seizures in veterinary patients. While these drugs are very effective in most animals and relatively inexpensive, the side effect profile is felt to be greater than newer anti-seizure drugs. Phenobarbital and bromide do require careful patient monitoring of drug levels and body systems.
Animals on Phenobarbital should have liver function tests (bile acids or ammonia), complete blood count, and serum biochemistry performed prior to initiating treatment and when blood drug levels are acquired.
Additionally, we suggest periodic blood work re-checks every six months as Phenobarbital can lead to liver dysfunction and bloodline alterations. Blood drug levels are also performed 14-21 days after the Phenobarbital dose is changed.
Drug levels are usually acquired 2-4 months after initiating therapy due to the long half-life and every 6 months thereafter. Animals that are experiencing unregulated seizure activity will need blood drug levels promptly.
Animals that frequently experience cluster or status events are often provided with diazepam (Valium) to administer rectally to halt events. Additionally, anti-seizure drugs with a short half-life (e.g. gabapentin or levetiracetam) can be administered as “pulse” treatment to shorten cluster events.
Most Frequently Affected Breeds
- Labrador Retriever
- Golden Retriever