Transient Remission In Intractable Localization‐Related Epilepsies of Childhood Onset.
Authors: Nakai Junko , Watanabe Kazuyoshi , Okumura Akihisa , Negoro Tamiko , Aso Kosaburo 
Published: August 2005

Purpose: About 10% to 20 % of patients with epilepsy have medically intractable seizures. In some patients, the intractable course may be interrupted by seizure‐free periods. Transient remission was reported in mesial temporal sclerosis (MTS) or focal cortical dysplasia (FCD), but few studies have examined this phenomenon in detail. We retrospectively reviewed 99 patients with intractable cryptogenic or symptomatic localization‐related epilepsy and studied the clinical features of those with transient remission lasting for >2 years.

Methods: We investigated 99 patients with cryptogenic or symptomatic localization‐related epilepsies who were treated in Nagoya University Hospital for >5 years and had medically intractable seizures. The underlying diseases of these 99 patients consisted of mesial tem‐ poral sclerosis (13 patients), tuberous sclerosis (9), hypoxic ischemic encephalopathy (9). central nervous system infection (7), iieuronal migration disorder (7), cerebrovascular disease (4), and periventricular leukomalacia (1). No underlying disease was determined in the remaining 49 patients. The epileptic focus was located in the temporal lobe in 37 patients, frontal lobe in 29, occipital lobe in 5, parietal lobe in 2, and was not determined in the remaining 26. The age of onset ranged from 0 month to 14 years (mean 4 years and 3 months). The duration of follow‐up ranged from 5 to 33 years (mean 15 years). The age at the last visit ranged from 9 to 34 years (mean 21 years). Eight (8%)patients had a family history of febrile convulsions, and 13 (I 3%) had a family history of epilepsy. Forty‐nine (50%) patients had mental deficits.

Result: Among 99 patients with intractable cryptogenic or symptomatic localization‐related epilepsies of childhood onset, 10 (10%) patients had transient remission that lasted for 2 years or more. The underlying diseases of these 10 patients consisted of mesial temporal sclerosis (3 patients), tuberous sclerosis (1), cortical dysplasia (I), intracranial hemorrhage (1), head trauma (1), and porencephalic cyst (1). No underlying disease was determined in the remaining 2 patients. The epileptic focus was located in the temporal lobe in 5 patients, frontal lobe in 2, and was not determined in the remaining 3 patients. Transient remission occurred within a few months after initiation of medical treatment if an appropriate anticonvulsant was given and lasted for 28 to 99 months. Epileptiforin discharges on the EEG disappeared in 7 patients during transient remission, and reappeared in 5 after recurrence of intractable seizures. Two (20%) patients had mental deficits, and 5 (50%) had a family history of epilepsy. Among 89 patients without transient remission, 57 (64%) patients had mental deficits, and 8 (9%) had a family history of epilepsy.

Conclusions: Transient remission in intractable localization‐related epilepsy occurs in a variety of pathological conditions and may reflect the progressive nature of some types of epileptic foci.