Cortical Dysplasia May Predispose to Both Febrile Convulsions(FC) and Refractory Temporal Lobe Epilepsy (TLE).
Abstract number :
D.06
Submission category :
Year :
2000
Submission ID :
1114
Source :
www.aesnet.org
Presentation date :
12/2/2000 12:00:00 AM
Published date :
Dec 1, 2000, 06:00 AM
Authors :
Brenda E Porter, Alexander R Judkins, A.g. Christina Bergqvist, Peter H Berman, Amy R Brooks-Kayal, Lawrence W Brown, Robert R Clancy, Dennis J Dlugos, Ann-Christine Duhaime, Susan E Melamed, Steven J Ryan, Jeffry A Golden, The Children's Hosp of Philadel
RATIONALE: The basis of the association between FC and subsequent refractory TLE is unknown, but two hypothesis have been advanced: (i) both FC and refractory TLE are caused by a common pre-existent structural abnormality of the temporal lobe. (ii) FC produce a permanent epileptic change in medial temporal structures. METHODS: To help distinguish between these two possibilities we studied the pathology of resected temporal lobes in patients with refractory TLE and prior history of FC seeking evidence of acquired or developmental abnormalities. The most common developmental lesion found was cortical dysplasia (CD), defined as a loss of normal cortical laminar organization with enlarged and maloriented clusters of cortical cells. RESULTS:Thirty-three patients underwent an isolated temporal lobectomy for refractory TLE at mean age of 12.2 years (SD 5.8) with an average unprovoked seizure onset at 3.9 years (SD 3.9). Fourteen patients had a history of febrile convulsions, with 6 having seizures lasting ?30 minutes. CONCLUSIONS: The proportion of CD in patients with FC (11 of 14; 79%) was significantly greater than those without FC (5 of 19; 26%) [Fisher's exact P=0.005]. Most patients (13 of 14; 93%) with prior FC had underlying pathologic abnormalities in their resected temporal lobes, with CD being the most common finding. The etiology of CD is unknown but is thought to be secondary to abnormal neuronal migration during prenatal life. CD is presumably present prior to the onset of FC and may lower the seizure threshold during fever.