Insulinoma misdiagnosed as intractable epilepsy

Abstract

Many conditions may mimic epileptic seizures, including movement disorders, cardiac arrhythmias, psychiatric disorders, or metabolic anomalies. Among these, insulinoma is a rare but curable cause of hypoglycemia often misdiagnosed as epilepsy or a psychiatric disorder. We report three patients with hypoglycemic spells caused by insulinoma. All patients were diagnosed during a video-EEG monitoring session initially performed for the evaluation of intractable epilepsy. ### Case 1. A 37-year-old woman had a 6-year history of stereotyped paroxysmal episodes of paresthesias of the left arm, spreading to the face and lower limbs, and lasting 20 minutes. Episodes could last up to 2 hours and included gait incoordination, mild agitation, emotional lability, and incoherent speech, which was followed by fatigue. Frequency of the attacks gradually increased up to twice a week. The patient was initially diagnosed with partial epilepsy, refractory to carbamazepine. No interictal activity was recorded during a prolonged video-EEG monitoring. Brain MRI was normal, and interictal SPECT revealed bifrontal and right posterior temporal hypoperfusion. A fasting blood glucose level was obtained and showed mild hypoglycemia at 3.2 mmol/L (normal, 3.8 to 6.1 mmol/L). …