Almost anything that irritates brain cells—a tumor, a stroke, an infection, a blow to the head—can cause a seizure. Such irritants disrupt the normal activity of neurons and cause them to fire inappropriately, triggering the electrical storm known as a seizure.
Often, the cause of a seizure is visible on a magnetic resonance imaging (MRI) scan, but sometimes, as in the case of Chief Justice John G. Roberts, the source of the irritation remains unknown. Because this is his second seizure, doctors are likely to look more aggressively for its cause.
When Roberts, 52, fell on a dock near his summer home on Hupper Island, Maine, on Monday, the Supreme Court's public information officer called it "a benign idiopathic seizure."
"Benign just means not very serious—not malignant, and also not recurrent," says Floyd E. Bloom, professor emeritus at the Scripps Research Institute and former editor-in-chief of Science. "Idiopathic just means we don't know what caused it."
However, Roberts had a similar seizure in 1993, which means Monday’s was a recurrence.
“People who have more than one seizure develop decreased thresholds for future seizures,” says Gregory Worrell, a neurologist at the Mayo Clinic. “Among people who have had only one seizure, only about 40 percent will have another, but among people who have had two, the chances jump to 60-70 percent.”
Roberts, however, is an ambiguous case.
“By the classic definition of epilepsy, which is two or more unprovoked seizures, Justice Roberts would fall into the category of epilepsy,” Worrell says. “But they were so far apart, I’d be inclined to treat this seizure as the first.”
Worrell adds that he would question Roberts very closely, however, about any other evidence of seizure activity.
“Often you’ll find that patients have been having small, discreet events that haven’t caused them to seek medical attention,” Worrell says. “Maybe they’ve had brief episodes where they have lost consciousness, or had brief amnestic episodes where they lost awareness of their surroundings.”
Another type of seizure can occur while people sleep.
“We ask patients if they ever woke up and found that they had lost their urine, or had a sore tongue, or were sore all over,” Worrell says. “Or they may have subtle seizures that involve lip-smacking or some other motor manifestation, and be unresponsive or confused. Often when you get a history you find they have indeed had more than one seizure.”
Roberts’ doctors probably will do an MRI scan of his brain to look for a tumor or a lesion, says Cynthia Harden, an associate professor of neurology at New York-Presbyterian Hospital/Weill Cornell Medical Center.
"They'll also look at his medical history to see if there has been a history of other events—confusional spells, for example, or nocturnal seizures," she says. "That would be cause for concern."
A check for signs of underlying disease such as lupus, diabetes, Lyme disease or brain infection is likely too, Harden says.
If the MRI and an electroencephalogram provide no explanation for the seizure, and if Roberts shows no sign of an underlying problem, "the chance of finding the cause is very low," Harden says.
As a result, Harden predicts the Chief Justice will end up taking one of the many anti-seizure medications now available, such as carbamazepine (Tegretol, Carbatrol), lamotrigine (Lamictal), and gabapentin (Neurontin).
With well more than a dozen common anti-seizure drugs available, patients have a good chance of finding one that will achieve the ultimate goal: no seizures and no side-effects. But sometimes a process of trial and error is necessary to find the best choice.
The most common side-effects are fatigue and drowsiness, but some patients also complain of dizziness, nausea, skin rashes, behavioral changes, sleep disturbances and other problems. The choice often comes down to such considerations as the patient’s age, other medical conditions and medications, and cost.
In addition, people who have had seizures should avoid anything that may lower their seizure threshold, such as excessive alcohol consumption or too little sleep.
The threat of having another seizure may affect a person’s quality of life. After his seizure in 1993, for example, Roberts gave up driving for a time, and this second seizure may require similar restrictions.
A sporadic seizure by itself poses little threat of brain damage. They last only a few seconds and terminate on their own.
“The problem generally is not the seizure itself, but what you’re doing when you have it,” Worrell says. “Driving an automobile or getting into a swimming pool—you have to be careful about any activity in which you could harm yourself or others.”
Status epilepticus, on the other hand, is a life-threatening medical emergency that involves a persistent seizure or a series of seizures lasting for several minutes. This condition seldom resolves itself, and it may cause brain damage in as little as 5 minutes. Such prolonged seizures usually result from a tumor, an abscess or a metabolic disorder.