Case Study

A 28 year-old white female had a febrile convulsion at 2 years of age. She developed normally and at 11 years experienced a GTC seizure. Subsequently she developed focal seizures with dyscognitive features that were associated with and without awareness. Seizures became resistant to multiple AEDs both singly and in combination. Following a severe burn she underwent a pre-surgical evaluation. MRI was demonstrated left mesial temporal sclerosis (MTS) and vEEG revealed left>right bitemporal spikes (80:20) and left rhythmic ictal theta onset for 3 seizures. She underwent a selective left amygdalo-hippocampectomy and perioperatively experienced 3 brief "petit mal" seizures in the first month that were "milder". CBZ ER 300 mg 2 PO BID was continued and GBP 600 mg 2 PO BID was titrated to 3 PO BID. She reported being seizure-free for 1 year and inquired about AED simplification. A sleep-deprived EEG was normal. A subsequent 24 hour computer-assisted ambulatory EEG was performed (see below).

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Figure: Computer-assisted ambulatory EEG demonstrating 5 detections of 2-second computer-based spike files demonstrating left mid-termporal spike-and-wave discharges maximal at T3 with a regional temporal field. Recording parameters are listed at the top of the graphic with EEG in a bipolar montage. monmontagem, and filters of 1-70 Hz.

What was ultimately wrong with the patient?

Mesial temporal temporal lobe epilepsy (mTLE) is the most common surgically remediable human epilepsy syndrome with MTS the most frequently encountered pathology. Seizure freedom is obtainable in approximately 70%, though beyond seizure freedom, successful taper from AEDs is a major aim of surgical pursuit. About 50% are able to be successfully tapered from AEDs and are ultimately "cured" of their epilepsy1. Favorable clinical signs for a successful taper in our patient include the presence of MTS and young age at onset. The long seizure duration before surgery, seizure occurrence prior to AED taper, and persistent interictal epileptiform discharges on EEG represent unfavorable signs. The sensitivity of scalp EEG to detect IEDs can be enhanced by obtaining both wakefulness and sleep. In addition, multiple recordings may enhance detection2. We recommended our patient continue her AEDs. No focal seizures with or without awareness were captured on prolonged 3 day CAA-EEG monitoring and she continues on CBZ monotherapy and is married, driving, and employed.

References

  1. Rathore C, Panda S, Sarma PS, Radhakrishnan K. How safe is it to withdraw antiepileptic drugs following successful surgery for mesial temporal lobe epilepsy? Epilepsia 2011;52(3):627-635.
  2. Mendez OE, Brenner RP. Increasing the yield of EEG. J Clin Neurophysiol 2006;23:282-293.
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Authored By: 
William O. Tatum DO
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Authored Date: 
05/2011