Convulsive Status Epilepticus—Clinical Lessons from Epidemiologic Findings

Abstract & Commentary

By Sabiha Merchant, MD, Instructor of Pediatrics and Neurology, Weill Medical College, Cornell University. Dr. Merchant reports no financial relationship relevant to this field of study.

Synopsis: Convulsive status epilepticus is common in children and prognosis is related to the underlying cause of the seizure disorder.

Source: Chin RF; et al. Incidence, Cause, and Short-Term Outcome of Convulsive Status Epilepticus in Childhood: Prospective Population-Based Study. Lancet. 2006;368:222-229.

North london convulsive status epilepticus Surveillance Study Group reported the incidence, cause, and short term outcome of status epilepticus in childhood. They prospectively identified 176 episodes of convulsive status epilepticus (CSE) over a 2-year period from a subset of their 18-hospital network. Important findings from this epidemiological study are the following:

1) The most frequent etiology for CSE in childhood was prolonged febrile seizures.

2) Case fatality for first ever episode of CSE was 3%.

3) Fatality was related to having a pathological cause for CSE, primarily bacterial meningitis and progressive neurodegenerative disorders.

4) CSE related to an acute symptomatic cause occurred frequently in children under one year of age.

5) Among children of all ages presenting with first ever episode of CSE, 56% were previously neurologically healthy with no history of epilepsy and no previous neurological deficits.

6) The short-term recurrence rate for CSE was 13%, with seizures most commonly recurring within 25 days of initial presentation. This short term recurrence rate was similar in both children with previous neurological abnormality and previously health children.

7) Children with a pre-existing neurological abnormality were 2.9 times more likely to have a recurrence after one year from the first episode, compared to previously neurologically normal children.

8) The incidence of CSE in children is higher than that for adult populations.

Commentary

This well executed, prospective study provides useful information regarding the frequency, causes, and mortality of CSE in children. The findings have several implications for clinical management. First, the most common cause of pediatric CSE is a prolonged febrile seizure which is associated with low mortality and morbidity. However, since a major cause of mortality was bacterial meningitis, this study reinforces the need to rule out acute bacterial meningitis in children presenting with CSE and a fever. Timely and vigilant emergent management is important for improving survival for these children.

Since CSE has a high recurrence rate within one year for children with underlying neurological impairments, these findings suggest that this population warrants careful consideration in prescribing antiseizure treatment after the first episode.

Caveats regarding the findings in the study are that the mortality rates may have been underestimated due to the small sample size, and no analysis was made regarding morbidity following CSE.