At least two unprovoked seizures more than 24 hours apartA known seizure cause that makes future seizures more likelyA known epilepsy syndrome (1)
An unprovoked seizure is one in which there is no cause identified aside from abnormal electrical activity in the brain. The term “unprovoked” is also sometimes used for seizures caused by a brain lesion or neurodegenerative process, because these carry a higher risk for future epileptic seizures. To determine whether symptoms are caused by epilepsy, other potential causes of seizures must be ruled out. There are many causes of epilepsy-like symptoms that are not caused by epilepsy. A wide variety of tests can help to rule out other causes for seizures and find out what part of the brain is seizing. With a more detailed diagnosis, better treatment choices can be made. The EEG is a standard test to assess the abnormal electrical brain activity that causes epilepsy. But some people who have epilepsy have a normal test, and some people without epilepsy have abnormalities that show up on an EEG. Another drawback of the EEG is that the seizures can be too deep in the brain to be detected by the electrodes that are placed on the scalp during the test. Sometimes a videotape is made of the person during a seizure while the EEG is also reading brain waves. This test is typically done in a hospital setting, where the seizure can be monitored. A video EEG allows specialists to compare the person’s brain waves with their symptoms, sometimes giving a more complete picture of what’s going on in the brain. When a person has his first seizure, the emergency department team may order a drug screen to see whether the person was exposed to recreational drugs. That’s because a number of drugs, such as cocaine, kratom, and PCP (phencyclidine, or “angel dust”) can cause seizures. (3,4) Seizures can also be caused by some prescription medications, as well as withdrawal from some prescription medications and alcohol. Some seizure disorders are syndromes caused by known genetic mutations, so genetic testing can be helpful in diagnosing these. Other blood tests can indicate that seizures were caused by an illness or by abnormal levels of electrolytes or sugar in the blood, not by epilepsy.
Magnetic resonance imaging (MRI) can reveal structural problems with the brain that may be causing seizures, like tumors or cysts. One type, called a functional MRI (fMRI), can be used to check for abnormalities in function.Computed tomography (CT) is used to look for bleeding or structural abnormalities in the brain that may cause seizures.Positron emission tomography (PET) is used to identify areas of lower metabolism in the brain, which happens after a seizure.Single photon emission computed tomography (SPECT) can be used to compare the brain blood flow during a seizure with the brain blood flow between seizures.
If the EEG, MRI, and lab work are all negative for epilepsy, the seizures could be nonepileptic, which means they are not accompanied by abnormal electrical activity in the brain, according to the Epileptic Society in the United Kingdom. The treatment for nonepileptic seizures is very different from epileptic seizures, so consider this diagnosis with your doctor if you meet the criteria.
Symptoms and duration of the seizures. If the person doesn’t remember the seizures or can’t recount them, a witness or caregiver account with as much detail as possible is helpful.Any information about family history of seizuresA history of any other medical or psychological problems and medications taken
Febrile seizures are a common type of seizure that children usually outgrow. Febrile seizures are triggered by fever and may occur in up to 5 percent of children ages 6 months to 5 years, according to research. If a child over 5 experiences a new onset seizure, even associated with a fever, a neurologist should be consulted. Because older people often have multiple health issues, it is important to rule out possible other causes for seizures rather than assume they’re caused by epilepsy. (6,7)
