Status Epilepticus in Childhood
Status Epilepticus in Childhood
ABSTRACT & COMMENTARY
Synopsis: Status epilepticus (SE) is relatively common in childhood. Some 10-20% of children with epilepsy will experience SE, and the number is even higher if children with febrile seizures are also considered.
Source: Shinnar S, et al. In whom does status epilepticus occur: Age-related differences in children. Epilepsia 1997;38:907-914.
Almost all neurologists, particularly those who care for children, have had considerable direct experience with the management and work-up of status epilepticus (SE). Despite this, little is known regarding the nature of conditions that lead to SE in various pediatric age groups. Shinnar and colleagues surveyed SE in 394 children aged 1 month to 16 years and report a number of useful findings.
Shinner et al subdivide SE in a manner similar to that suggested by the International League Against Epilepsy.1
• Cryptogenicno obvious precipitant, in a patient not previously believed to be at increased risk for seizures.
• Remote symptomaticno obvious precipitant, in a patient with a known CNS insult or medical condition with an increased risk for seizures.
• Acute symptomatican obvious acute precipi- tant, other than fever.
• Febrilesole acute precipitant is fever.
• With progressive encephalopathy-seizures occurring in the context of progressive neurologic disease.
Subjects were gathered from patients seen in emergency rooms and/or during hospital admissions. Patients with recurrent SE were entered only once. Due to the ascertainment procedures, most of the patients (89%) had not had a previous episode of SE.
More than 50% of childhood SE cases occurred before age 3, and only about 25% occurred after age 6. Whether first SE or a recurrent episode, some cause could be found for about 85% of patients. SE occurred in the context of progressive encephalopathy in only about 5% of children.
Among children younger than age 3, the major subtypes observed were febrile and acute symptomatic SE, whereas, older than age 6, remote symptomatic seizures predominated. To summarize: SE in young children usually reflects a normal brain responding to abnormal conditions, whereas SE in older children usually indicates a constitutively lower seizure threshold. Acute symptomatic SE should be assumed until proven otherwise; the major etiologies found among the 109 patients in this category were CNS infection (29%), transient metabolic disturbances (25%), trauma (17%), and anoxia (12%).
Among the 394 patients examined, approximately 40% were known to be neurologically abnormal prior to the episode. However, among patients with recurrent SE, prior neurologic abnormalities existed in about 60%. In patients with no prior history of unprovoked seizures (SE or otherwise), neurologic abnormalities affected only about 20%. Thus, young (< 3 years old) patients with SE and no prior history of unprovoked seizures would be expected to have a much lower incidence of underlying brain pathology than older (> 6 years old) patients with recurrent SE.
COMMENT BY ROSARIO TRIFILETTI, MD, PhD
An important strength of this epidemiological survey is that two cohorts obtained at different times and with different patient populations were examined. The fact that quantitatively similar results were obtained in each cohort bolsters the conclusions of the paper. Neurologists should continue to view SE in children as a diagnostic and therapeutic emergency, despite the apparent difference in implications of SE in the younger child without prior unprovoked seizures and the older child with a history of recurrent SE. (Dr. Trifiletti is Associate Professor of Pediatric Neurology, New York Hospital, Cornell Medical Center.)
Reference
1. Commission on epidemiology. Guidelines for epidemiologic studies on epilepsy and prognosis. Epilepsia 1993;34:592-596.
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