Abstracts

Rationale: Occult temporal encephaloceles have been implicated in the development of temporal lobe epilepsy in several studies. There are few reported cases of frontal lobe epilepsy caused by encephaloceles. We report a case of sphenoidal encephalocele as the cause of poorly controlled nocturnal frontal lobe seizures.

Methods: A 40-year-old woman with a history of obesity, migraine, remote TBI (occurred at age of 10), and obstructive sleep apnea began to have new onset nocturnal convulsions. Routine EEG and previous brain MRI were reportedly normal. After failing Vimpat and topiramate, she was put on levetiracetam 1000 mg twice daily, but she continued to have seizures including one episode of status epilepticus. She was admitted to the EMU for further evaluation.

Results: The EEG did not show interictal abnormalities for several days but one nocturnal seizure was captured. The EEG onset of the seizure preceded clinical onset for approximately one hour, consisting of fluctuating admixture of generalized and left frontotemporal rhythmic delta activity. Just prior to clinical onset, there was increased rhythmicity and evolution of morphology to epileptiform sharp waves over the left frontotemporal region. At clinical onset, the semiology consisted of an ictal cry, eye deviation to the left, and hypermotor movements that progressed to generalized tonic-clonic convulsions with eye deviation to the right lasting 65 seconds. MRI brain revealed an encephalocele arising from the posterior orbitofrontal region of the left frontal lobe through a defect along the roof of the left sphenoid sinus. Additionally, there was mild edema in the left hippocampus and the base of the temporal lobe. She underwent CSF leak repair and encephalocele resection, has remained seizure free since surgery.

Conclusions: We describe the case of a 40-year-old woman with new onset nocturnal frontal lobe seizures likely caused by a sphenoid encephalocele. The bony defect is probably related to her remote TBI. The formation of this sphenoid encephalocele had been a chronic process, which did not cause neurological symptom until decades later, indicating that frontal lobe encephalocele may be asymptomatic when the size is small. Sphenoid encephaloceles are rare and to our knowledge, have not been previously associated with this clinical presentation.

Funding: Please list any funding that was received in support of this abstract.: n/a.