Abstract
A 27-year-old female was admitted to our hospital in November1979 because of frequent episodes of mental confusion and/or episodes of coma. In December 1974, she had an attack of paresthesia of the hands and legs followed by unconsciousness. She experienced similar episodes once a month and was given diphenylhydantoin and carbamazepine for 5 years, after a diagnosis of symptomatic epilepsy.
On admission, the blood sugar was found to be 32 mg/dl. Mental function and cranial nerves were normal. There was weakness and wasting in the distal leg muscles. All tendon reflexes in the lower limbs were absent. There was tingling and numbness in her hands and feet. Needle EMG studies provided evidence of denervation of small muscles ofthe hand and of distal muscles in the legs. The right median nerve motor conduction velocity and right sural nerve conduction velocity were reduced slightly, while the left peroneal motor and right median and ulnar sensory action potentials were not evoked. The histologic findings in the peroneus brevis muscle were consistent with the neurogenic changes. A sural nerve biopsy disclosed a slight reduction in large myelinated fibers and the presence of Schwann cell clusters.
These findings are consistent with axonal degeneration. Following removal of the insulinoma, the patient showed remarkable improvement in paresthesia of the hands and legs, and slight improvement in motor conduction velocity. This situation suggested that hypoglycemia in the insulinoma resulted in the peripheral nerve damage. We now report for the first time in Japan, the occurrence of peripheral neuropathy in association with insulinoma studied histologically and electrophysiologically.
