ORLANDO—In the pediatric age-group, sudden unexplained death in epilepsy (SUDEP) is "unlikely," according to a study from Nova Scotia. Although SUDEP is a frightening reality it is also very rare, said Carol S. Camfield, MD. Among 693 children in the study, only one death was attributed to SUDEP—and it occurred after childhood.

Since the risk of SUDEP can influence treatment decisions, actual rates are important to establish, said Dr. Camfield and her colleague, Peter R. Camfield, MD, both of Dalhousie University in Halifax. They based their study on records from the Nova Scotia Childhood Epilepsy Database, a population-based cohort that identified all children diagnosed with epilepsy between 1977 and 1985. The database lists 693 children with epilepsy in the population of 850,000. Of the 693 children, 74% had been diagnosed with either generalized tonic-clonic focal or focal secondary generalized epilepsy, 14% with absence seizures, and 12% with other generalized symptomatic epilepsy.

In 1999 the researchers searched Nova Scotian death and marriage registries and identified 25 (3.6%) of the 693 children who had died from various causes, reported Dr. Carol Camfield at the 53rd Annual Meeting of the American Epilepsy Society. Death certificates, autopsy reports, and physician records were then examined, and families were contacted to establish causes of death.

AN "INTERESTING" DISTRIBUTION BY SEIZURE TYPES

The death rate was 0/97 for children with absence epilepsy; 12/511 (2%) for those with partial and primary generalized epilepsy; 4/49 (8%) for those with secondary generalized epilepsy with onset after 1 year of age; and 9/36 (25%) for those with secondary generalized epilepsy with onset before 1 year. "It's interesting to look at the epilepsy and seizure types of these children," Dr. Camfield said. "In the absence group of 97 children, none died. In the children with partial and primary generalized epilepsies, 2% died, or 12 of 511 children." Of the 85 children with other generalized epilepsies, 13 (15%) died.

The children whose deaths were "expected" died at an average age of 7 years (range 1.5 to 16). Fourteen children with cerebral palsy and developmental disabilities died from aspiration with pneumonia. Most of those children had been diagnosed with epilepsy before the age of 1, said Dr. Camfield. "Three children died of sepsis and one each of shunt malformation, pulmonary embolism, and congenital heart failure." Another child failed to thrive, and one child died of multiple prolonged episodes of status epilepticus after being hospitalized for approximately eight days, she reported.

The three "unexpected" deaths were caused by homicide (at age 20), suicide (at age 30), and probable SUDEP (at the age of 21).

ONE CASE OF SUDEP

"The child who died from probable SUDEP was a mildly mentally handicapped 21-year-old with tuberous sclerosis, frequent seizures, and poor medication compliance," Dr. Camfield said. "She was diagnosed as having partial complex seizures and focal secondarily generalized seizures. At the time of diagnosis, she was noted to have lesions typical of tuberous sclerosis. She also had a normal neurologic exam. She had a mild mental handicap and a normal CT scan, with her EEG showing focal temporal spikes. In addition, she had moderate asthma requiring daily medication off and on throughout her life up to the time of her death." She had no known history of status epilepticus.

She had initially been treated with carbamazepine. "She had 12 seizures during the first year of treatment. She was depressed about this and certainly proved to be unhappy when she had three to four seizures per month over the next four years. The longest seizure-free interval was six months. At age 19 years, phenytoin was added by the local family doctor," said Dr. Camfield. The patient had a history of noncompliance with medication and physician appointments. At the time of death she was taking carbamazepine and phenytoin, but compliance was unknown.

The patient had several seizures the night before her death. According to her boyfriend, she was up and walking about the house that morning. However, by 2:00 pm she was found to have died in bed. The autopsy, said Dr. Camfield, showed mild pulmonary laryngeal edema and small airway changes compatible with a history of asthma. Gross and microscopic examinations of her heart, brain, and kidneys were normal.

The coroner who performed the autopsy referred the slides to the provincial coroner for evaluation. "There was an antiepileptic drug level drawn at the time of her death after the toxicology studies, but 10 years down the line I really haven't been able to track those levels down. There is no mention that they were abnormal or that that they were normal," Dr. Camfield said.

"I don't know if she died of status epilepticus; I don't know if she had cardiac arrhythmia; I don't know if she had asthma," Dr. Camfield added. For the purposes of the study, this death remains probable SUDEP, she said—the only case in the cohort. Overall, Dr. Camfield concluded, the findings suggest that "parents may be reassured that their children with epilepsy are exceedingly unlikely to die from SUDEP."

—Debra Hughes
Contributing Writer

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