Teaching Case

Partial complex seizures

The patient had partial complex seizures of left temporal lobe origin. He underwent an MRI study including proton MR spectroscopy (TR=1500 msec, and TE=135 msec), 8 hours after the last seizure. Proton MR spectroscopy was repeated 1 month later using the same imaging parameters, when the patient was seizure-free.

The most common cause of temporal epilepsy is atrophy in the hippocampus, which is referred to as hippocampal sclerosis. Other causes include tumors, arteriovenous malformations, neuronal migration anomalies, and encephalomalacia. On the other hand, it should be noted that an epileptogenic condition referred to as nonspecific cortical gliosis, in which surgically resected tissue specimens reveal no definite abnormality, can also occur with relatively high prevalances. In patients with hippocampal sclerosis main spectroscopy findings include decreases in N-acetyl aspartate (NAA), and increases in lactate and lipids. In the current patient with MRI evidence of hippocampal sclerosis, decreased NAA levels were noted in two spectroscopy examinations one month apart. Lipids were increased in the initial examination obtained 8 hours after the last seizure, and they returned to normal in the spectroscopy examination one month later, when the patient was seizure-free. These findings suggest that lipids may be a sensitive marker for acute temporal lobe seizures.