Seizures In Dogs And Cats
By Emily Hoppmann, DVM
There are numerous potential causes of seizures in dogs and cats, but regardless of the cause the seizure is a result of excessive, disorganized electrical brain activity that is not consciously controllable. Generalized seizures are either convulsive (also known as grand mal) or non-convulsive (also known as petit mal) seizures. Generalized seizures are the most common type of seizures seen in animals and are characterized by loss of consciousness along with symmetric stiffening, paddling, and sometimes loss of movement in the limb muscles. Partial (also known as focal) seizures can also be seen and these occur when only a portion of the body is affected (for example only one side of the face). The most common cause of seizures is idiopathic epilepsy, meaning that there is no obvious cause of the seizures. The severity of the cause of the seizure does not necessarily match the severity of the seizure. For example, dogs with idiopathic epilepsy may have severe generalized seizures when a dog with a brain tumor may only have partial seizures.
Whether the seizure is caused by an issue within the brain (intracranial) or outside of the brain (extracranial), they can look exactly alike. Therefore, two crucial aspects when seizures are suspected are to be sure that it is a seizure that has occurred and not a different type of problem (such as liver shunts, low blood sugar, heart arrhythmias, etc.) and to identify whether the cause is intracranial or extracranial. There are multiple diagnostic tests that will need to be done to identify the cause, but the most common starting point is a good history from the owner, a comprehensive physical exam and general blood work. Often times a reason for the seizures is not found even with extensive testing and the seizures are diagnosed as idiopathic.
Seizures are often preceded by unusual behavior or a mood change that can last for minutes to days. This time period is called the preictal phase of a seizure and may or may not escape notice because of its subtle effects. The behavior changes that may be seen include hiding, attention-seeking, restlessness, whining, or howling. The actual seizure is known as the ictal phase and can last from a few seconds to several minutes. The most common appearance includes altered consciousness or unconsciousness, falling to the ground and lying on the side of the body, rhythmic muscle contractions such as paddling/jerking of the legs and/or “gum-chewing” motions with the jaws, salivation, urination, and defecation. There is no responsiveness to verbal commands because the animal is in an altered state of consciousness while this is happening. After a seizure, the postictal phase occurs and this is the recovery stage after the seizure. Some dogs and cats continue to lie on their side for a few minutes, and some fall into a deep sleep. Most are disoriented and may wander around, stumbling aimlessly and restlessly. They may appear temporarily blind or deaf. These behaviors can last from minutes to hours; rarely do they persist for a day or more. It is important to note the time-frame associated with the three phases of the seizure because it provides a great deal of helpful information when categorizing the seizure and determining what diagnostics and treatments are necessary. Typically when there is just a single seizure and blood work is normal, a patient is not started on medication until the number of seizures in a set time frame increases (usually more than 3 seizures in 2 months) or the seizures occur in a cluster (within 24 to 48 hours).
A dog or cat diagnosed with a seizure disorder may require lifelong medication, depending on the actual underlying disorder causing the seizures. Sometimes, seizures may continue to occur despite medication, and in these cases, recheck visits are important to make sure that the medication doses are adequate and there are no other medical conditions occuring. It is important to keep your pet as comfortable as possible before, during, and after seizures. If you recognize a preictal phase, you can help to prevent injury by not allowing your pet to go up and down steps or to jump on and off furniture, which could be hazardous if the seizure begins at that time. Keep your hands away from the mouth during a seizure to prevent being bitten; during a seizure, the animal has no conscious control or recognition and may inadvertently bite any hand that is near his/her face. The old wives’ tale of patients “choking on their own tongue” during a seizure is not true. Talking calmly and softly to your dog or cat may help smooth the recovery.
Once the determination that treatment is needed, the goal is to find the cause of seizures and eliminate it with treatment if possible. This is possible in some cases and not others, depending on the specific underlying disorder that is causing the seizures. For example, lead poisoning, liver disease, meningitis, and many other diseases can be treated with medications that reduce or eliminate the cause itself, making seizures less likely to occur. On the other hand, brain tumors that are inoperable will continue to cause seizures because the underlying cause cannot be removed or idiopathic seizures (whose cause is unknown) can only be treated with drugs that make seizures less likely to happen (anticonvulsant drugs). Once treatment with anticonvulsant drugs has been started, it must be given for the life of the patient and stopping the medication can cause a more severe seizure than the patient ever had before (which can be life-threatening). The levels of the drug in the body have to be monitored every 6 months to be sure they are in the therapeutic dose and do not need to be adjusted.
Seizures in your pet are very scary and overwhelming since there is nothing you can do to help your pet during the seizure. It is important to keep notes about the occurrence of the seizure and any details before, during, and after the seizures in a journal so you can provide this information to the veterinarian. The first time your pet has a seizure, you should seek immediate veterinary care so that the process of determining the cause can be started as promptly as possible and so that an individualized plan can be made to avoid your pet having future issues. Again, most seizures are idiopathic, but there are very good medications to help control the frequency and severity of the seizures. We are here to help and be your partner when dealing with this stressful disease.