In Brief: When is it epilepsy?
When is it epilepsy?
In vulnerable people, emotional conflict, stress, or an abnormal need for attention can result in symptoms that uncannily resemble true epileptic seizures. These episodes, once called pseudoseizures, are now usually called psychogenic nonepileptic seizures or attacks. Psychiatric disorders, especially conversion disorder are a common cause. As many as 20% of patients with genuine epileptic seizures may also have psychogenic seizures.
The most reliable way to tell the difference is to measure brain electrical activity during the episode with electroencephalography (EEG). Video recording of the event can also be helpful. But these methods are not perfect and, more important, are often not available in an emergency. Two papers published in 2006 in the journal Neurology suggest other tests that can be used during and shortly after a seizure.
In a German study of 147 seizure episodes, researchers used medical records to compare generalized (grand mal) epileptic seizures with similar psychogenic seizures. The retrospective diagnosis was based on EEG and other signs. Patients with psychogenic seizures were 17 years younger, on average, and half of them had a venous access port, an implanted device that allows drugs to be injected intravenously without repeated needle sticks. Compared to patients with true epilepsy, they required a much higher dose of the anti-seizure drug diazepam (Valium), either because they had developed tolerance to the drug or because less is needed to stop a seizure than to sedate a person undergoing a nonepileptic event. Blood levels of creatine kinase, measured a few hours after the seizure, were high in patients with true epileptic seizures but normal in those with psychogenic seizures. Creatine kinase is an enzyme needed by muscle cells; it pours into the blood when convulsions damage those cells.