Drug-resistant epilepsy (DRE) comprises around 1/3 of epilepsy patients.  Encephaloceles are increasingly recognized as a DRE cause with an unknown incidence and prevalence. It can take ≥15 years to identify encephaloceles in DRE patients, with severe implications for quality of life and costs of care. In many cases, surgical resection/repair can be curative.

We identified 48 patients with epilepsy and encephaloceles in our Epilepsy Clinic. Twenty-eight (58%) were female; the mean age was 48.6 years (range 25-85). The average time from epilepsy onset to encephalocele discovery was 7.5 years (SD 8.4). Thirty-three (75%) met criteria for DRE. Twenty-three (48%) had no epilepsy risk factors, but in patients that did, trauma was the most frequent (13 pts, 27%).

A lack of aura (14 patients, 29%) and psychic aura (déjà vu) (10 patients, 21%) were the two most frequently occurring auras. A slight majority had focal to bilateral tonic-clonic seizures (27 pts, 56%). Most encephaloceles were temporal (97%). A majority of encephaloceles were of unknown etiology (67%); 17% had associated venous sinus stenosis and 11% had trauma and IIH as possible etiologies, respectively.

Clinical, imaging, and electrophysiologic evaluation (scalp/invasive EEG) estimated that 68% of encephaloceles caused epilepsy. Nine patients underwent epilepsy surgery. No patient undergoing surgery died.

Most of our patients with epilepsy and encephaloceles met criteria for DRE. Early encephalocele recognition in DRE patients, followed by a prompt pre-surgical evaluation may impact seizure control, quality of life, and the financial burden of DRE on individual patients and health care systems.