Featured Case – November 2012

This case was contributed by Ekrem Kutluay, MD, Associate Professor of Neurosciences, The Medical University of South Carolina Comprehensive Epilepsy Center

The patient is a 22-year old male with history of seizures since the age of 11 years old. He initially was diagnosed with seizure disorder after two witnessed generalized tonic-clonic seizures (GTC). However, his mother remembers occasional daydreaming episodes two years prior to his seizures although those were not officially diagnosed. He was put on carbamazepine and the dose was titrated to 200 am and 400 pm. He was seizure free for 3 years but had another GTC. Afterwards, he was seizure free for 4 more years. At that time, his doctor decided to wean him off of carbamazepine slowly. This was done over few weeks but he had another GTC 3 months after he stopped his medication. He was then started on levetiracetam but developed psychological side effects and switched back to carbamazepine again. He was on 600 mg/day of carbamazepine for slightly more than a year when he presented to epilepsy outpatient clinic. History was gathered from him and his mother. He claimed that he did not have any more seizures after he started back on carbamazepine again and his main complaint was increasing cognitive decline. He complained extreme forgetfulness, difficulty in focusing and constant “fogginess” in his brain. He thought this was mainly due to carbamazepine side effect and he felt overmedicated. His recent routine EEG revealed mild background slowing without any electrographic seizures or interictal epileptiform activity. MRI of the brain was also unremarkable. Lamotrigine was added to his carbamazepine and dose was increased slowly to 100 bid over few weeks. Then he was weaned off carbamazepine completely. During his follow up visit in clinic, he denied any improvements in his symptoms although he was not taking carbamazepine for more than a month.

Question: What could be contributing his mental slowness?

The patient was admitted to hospital for 24-hour vEEG study to rule out subclinical seizures. His EEG revealed several electrographic seizures originating from left temporal region, ranging from 15 seconds to few minutes (Fig 1a and 1b: Left temporal seizure). He was not aware of the situation during any of them; however, he somehow looked confused in the video during some of them and was slow to answer questions during one of the prolonged seizure.

Partial onset seizures (simple or complex) sometimes may manifest in subtle and unusual ways. Mental fogginess and steady cognitive decline can be a manifestation of subclinical seizure activity. High index of suspicion is crucial especially if no improvement is observed like the case described above. Routine 30-minute EEG study may not be long enough to capture necessary information for correct diagnosis.

Last updated: September 12, 2018

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