THE TRANSITORY LOWERING of blood sugar caused by functional hyperinsulinism can act as a metabolic trigger for an epileptic seizure, even if the potential for such a seizure is only latent. The patient described in this paper represents such an instance. In this case the seizures were limited to vertigo.1
Most vertiginous seizures have their origin in the temporal lobe. Penfield and Kristiansen2 found that eight of nine patients whose seizures began with vertigo had lesions of the posterior temporal gyrus. Electrical stimulation of these lesions reproduced the vertigo of the seizure aura. When an abnormal neuronal discharge was limited to this area, the seizure was limited to vertigo.
It is known that hypoglycemic convulsions can be caused by administered insulin, pancreatic adenoma and postgastrectomy hypoglycemia. Functional hyperinsulinism has not been shown to cause convulsions. This is apparently due to the fact that the hypoglycemia is less severe