How long does it take for epilepsy to become intractable? A prospective investigation

• Published in: Annals of neurology 2006-07, Vol.60 (1), p.73-79
• Main Authors: Berg, Anne T., Vickrey, Barbara G., Testa, Francine M., Levy, Susan R., Shinnar, Shlomo, DiMario, Frances, Smith, Susan
• Format: Article
• Language: English
• Subjects: Adolescent; Age of Onset; Anticonvulsants - therapeutic use; Biological and medical sciences; Child; Child, Preschool; Connecticut - epidemiology; Degenerative and inherited degenerative diseases of the nervous system. Leukodystrophies. Prion diseases; Drug Resistance; Epilepsies, Partial - drug therapy; Epilepsies, Partial - epidemiology; Epilepsies, Partial - surgery; Follow-Up Studies; Headache. Facial pains. Syncopes. Epilepsia. Intracranial hypertension. Brain oedema. Cerebral palsy; Humans; Infant; Infant, Newborn; Medical Records; Medical sciences; Nervous system (semeiology, syndromes); Neurology; Prospective Studies; Remission Induction; Risk Factors; Time Factors; Treatment Failure
• ISSN: 0364-5134; 1531-8249
• DOI: 10.1002/ana.20852

Objective To determine prospectively when in the course of epilepsy intractability becomes apparent. Methods Data are from a prospective cohort of 613 children followed for a median of 9.7 years. Epilepsy syndromes were grouped: focal, idiopathic, catastrophic, and other. Intractability was defined in two ways: (1) 2 drugs failed, 1 seizure/month, on average, for 18 months (stringent), and (2) failure of 2 drugs. Delayed intractability was defined as 3 or more years after epilepsy diagnosis. Results Eighty‐three children (13.8%) met the stringent and 142 (23.2%) met the two‐drug definition. Intractability depended on syndrome (p < 0.0001): 26 (31.3%) children meeting stringent and 39 (27.5%) meeting the 2‐drug definition had delayed intractability. Intractability was delayed more often in focal than catastrophic epilepsy (stringent: 46.2 vs 14.3%, p = 0.003; two‐drug: 40.3 vs 2.2%, p ≤ 0.0001). Early remission periods preceded delayed intractability in 65.4 to 74.3% of cases. After becoming intractable, 20.5% subsequently entered remission and 13.3% were seizure free at last contact. Interpretation Intractable epilepsy may be delayed, especially in focal epilepsy. It often is preceded by a quiescent period, followed by further remissions. These findings help explain why surgically treatable epilepsies may take 20 years or longer before referral to surgery. Ann Neurol 2006