Structural brain lesions do not influence the prognosis of juvenile myoclonic epilepsy

Objectives - In juvenile myoclonic epilepsy (JME) neuroimaging procedures a re usually unnecessary but are often performed following the first generali zed tonic-clonic seizure before a specific diagnosis has been reached. Our aim was to evaluate the influence of abnormal findings on the clinical pres entation and prognosis of JME. Material and methods - We retrospectively an alyzed all medical records of JME patients first referred in two epilepsy c enters (Marseilles, Nice) between 1981 and 1998. Results - Among 170 consec utive unselected newly diagnosed JME patients, neuroimaging was performed i n 82 cases (MRI: 22, CT: 75, including MRI + CT: 15). In 4 subjects, specif ic neurological abnormalities had justified neuroimaging: severe head traum a after the onset of JME (2, both with lesions related to the trauma), mult iple sclerosis with onset after JME (1, with normal MRI before the onset of multiple sclerosis and abnormal, specific findings later), severe mental r etardation (1, with diffuse MRT changes but a typical electro-clinical pres entation and evolution). In the other 78 cases, 9 had abnormal findings: co mmon arachnoid cyst (3), mild diffuse cerebral atrophy and ventricular enla rgement (1), mild ventricular enlargement only (3), septum lucidum cavum (1 ), mildly increased T-2 signal in the left temporal lobe (1). Abnormal neur oimaging did not influence therapeutic decisions or prognosis. Conclusions - These data confirm that neuroimaging procedures should not be routinely p erformed in patients with typical JME, unless additional neurological probl ems, that are unrelated to the diagnosis of epilepsy, occur.