Complex partial seizures/ temporal lobe epilepsy

One of the most common type of seizures seen in the adult population is what are called complex partial seizures. As the name suggests these are partial seizuresĀ  meaning that only a part of the brain has the seizure (remember in generalized seizures the whole brain has the seizure and hence the patient clinically has a convulsion, read my posts on epilepsy and seizures at http://braindiseases.info). Complex partial seizures differ from simple partial seizures. While in simple partial seizures there is no disturbance in the patient’s level of consciousness (the patient is awake and alert), in complex partial seizures there is an impairment in the level of consciousness. The patient may have his or her eyes open but usually is unable to respond or communicate. He may or may not comprehend if you try to speak to him during a seizure episode.

As many of the complex partial seizures arise from the temporal lobes in the brain, epilepsy of this kind is also referred to as temporal lobe epilepsy (TLE). That said and done complex partial seizures may also arise from the frontal lobes. Seizures arising from the frontal lobes can present with bizzare clinical manifestations, patient may become hyperactive during the seizure andĀ have strange bicycling like movements of the legs. Complex partial seizures are at times associated with an aura. A simple way to define aura is what happens usually before the seizure. Prior to the onset of a seizure, the patient may experience gustatory or olfactory auras (smell of burning rubber, metallic taste in the mouth are the different classical auras mentioned in the textbooks of neurology). Other patients may mention they “feel wierd” or “dizzy”. Others mention a rising sensation in the stomach.

During the seizure apart from impairment in the level of consciousness, patients frequently exhibit what we refer to as automatisms. These are semi-purposeful movements. Examples include lip-smacking, chewing movements, tongue protusion, picking at the clothes (semi-purposeful movements of the hands). These patients may or may not have a “convulsion”. If the seizure spreads and becomes generalized then they go into a convulsion (such seizures are referred to as partial with secondary generalization).

If an adult presents with a new onset complex partial seizure, neuroimaging is warranted. This is because a new onset complex partial seizure raises the suspicion for an underlying structural lesion in the brain such as a cyst or a tumor (though I want to emphasize here that the most common cause of new onset seizures in the elderly is vascular, meaning a previous stroke).

Work-up for TLE includes an EEG, if needed a long term EEG recording (we call this a video-EEG study), imaging studies like CT scan (though the study of choice is what is called a MRI scan of the brain done under the epilepsy protocol). Thin slices are taken to look at the temporal lobes and hippocampus to make sure there is no structural lesion there nor is there any evidence for mesial temporal sclerosis (MTS).

There are many effective drugs for complex partial seizures/TLE. The most commonly used are carbamazepine (Tegretol) and oxcarbazepine (trileptal). If the seizures are refractory to medications, these patients can be worked up for epilepsy surgery (see my post on epilepsy surgery at http://braindiseases.info).

Nitin Sethi, MD