RISK OF SUDDEN UNEXPECTED DEATH IN EPILEPSY DUE TO TUBEROUS SCLEROSIS: A RETROSPECTIVE COHORT STUDY

Objectives: Epilepsy is associated with an increased risk of sudden unexpected death (Sudep). This risk is thought to be higher in those with learning difficulty and those with symptomatic epilepsy. Tuberous sclerosis is a genetic disorder with approximately 50% of affected individuals having severe learning difficulty and 75% having symptomatic epilepsy. We undertook a retrospective case note review of all patients seen in our tuberous sclerosis clinic to estimate the risk of Sudep.

Methods: Complete ascertainment of patients was possible because comprehensive records have been kept. Patients seen on only one occasion or who were not followed up for more than one year were excluded from the analysis. Risk factors for Sudep were extracted from the notes. Results: There were 698 years of follow up of 110 individuals with epilepsy, 73 with learning difficulty and 44 with a known history of infantile spasms. During this follow up, two individuals with a history of epilepsy died suddenly and unexpectedly suggesting an incidence rate of 2.9 per 1000 person years. One with severe learning difficulty had epilepsy with daily seizures including tonic clonic seizures and drop attacks. The other individual was of normal intellect and had had no seizure for 4 years but was taking one antiepileptic. Within the 698 person years of follow up, 357 person years involved treatment with more than one antiepileptic drug and 132 person years with more than two.

Conclusion: The risk of Sudep in this cohort is much less than that quoted for other similar high-risk cohorts of epilepsy and learning difficulty patients.