Source:Berg AT, Shinnar S, Levy SR, et al. Early development of intractable epilepsy in children: a prospective study.
Neurology.
2001
;
56
:
1445
–1452.

The early identification of children at risk for intractable epilepsy (IE) would facilitate a more aggressive and, perhaps, more effective medical or surgical management. Children with newly diagnosed epilepsy were prospectively identified by participating pediatric neurologists in Connecticut from January 1993 through December 1997. Parental interviews and follow-up medical record reviews and analyses were conducted by researchers at Montefiore Medical Center in Bronx, NY, Yale, and Northern Illinois Universities. Median follow-up was 4.8 years, and 98% were followed for more than 18 months. Intractability was defined as at least 1 seizure per month over 18 months despite treatment with 2 or more drugs. Only patients with intractable seizures occurring within 2 years of diagnosis were included. Drugs were titrated to maximum tolerable doses and noncompliance was ruled out. Of a total of 613 newly diagnosed cases (median age 5.3 years), 60 (10%) met criteria for intractability. Thirty-five percent (18/52) were classified (according to International League Against Epilepsy guidelines)1 as cryptogenic/symptomatic genera1ized epilepsies, 2.7% (5/184) as idiopathic, 10.7% (31/290) as other localization-related, and 8.2% (6/73) were unclassified. Risk of intractability was highly correlated with etiology and syndrome (P<.001). The highest risk of IE was in the symptomatic (eg, secondary with CNS pathology such as anoxic brain damage) group and the lowest in the idiopathic (eg, primary or genetic and without CNS pathology) cases. IE was also correlated with a high initial seizure frequency (an interval of .5 months vs 4.7 months between 2 seizures) (P<.0001); focal EEG slowing (P=.02); and acute symptomatic or neonatal status epilepticus (P=.001). Age at onset between 5 and 9 years was associated with a lowered risk of IE (P=.03). Factors not significantly correlated with early intractability included age of onset less than 1 year, absolute number of seizures and duration of epilepsy, and unprovoked (by fever or other known stimulus) or febrile status epilepticus.

The prognosis of intractable epilepsy (IE) may be improved by a more timely selection of cases for trials of newer antiepileptic drugs, and surgical or dietary methods of management. The authors have provided some valuable data on the risk factors for IE. Epilepsies are grouped as localization-related (focal, local, partial) or generalized.1Localization-related epilepsies are idiopathic/genetic (eg, benign childhood epilepsy with centrotemporal spikes [BECTS]), or symptomatic/cryptogenic (of known or unknown etiology). Generalized epilepsies are grouped as idiopathic with age-related onset (eg, benign neonatal, benign myoclonic in infancy, childhood and juvenile absence), symptomatic, and idiopathic and/or symptomatic (eg, West’s and Lennox-Gas-taut syndromes). Idiopathic or primary forms of epilepsy usually carry a better prognosis. As might be expected, symptomatic generalized epilepsies, a high initial seizure frequency, and focal EEG findings correlate with an intractable course.

The validity of predicting intractability based on these criteria is questioned by some authorities.2 Is failure to respond after...

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