Reversible brain cell damage due to hypoglycemia in a patient with insulinoma

A case of hypoglycemic hemiparesis and literature review

An 89-year-old man with diabetes treated with metformin 500 mg/day and glimepiride 4 mg/day was hospitalized because of hypoglycemic right hemiparesis and dysarthria (casual glucose value 1.8 mmol/L), which resolved quickly following administration of 40 mL of 40% dextrose. Hemiparesis is a rare symptom (4.2%) of hypoglycemia. There are about 200 case reports of hypoglycemic hemiparesis. The average glucose level at which hemiparesis developed was 1.8 mmol/L. Right-sided hemiparesis predominated (R 66%; L 34%). On imaging studies, abnormal findings were frequently observed in the internal capsule or splenium of the corpus callosum. The mechanism of hemiparesis is not fully understood. The existence of cases in which hypoglycemia cannot be distinguished from stroke on imaging studies suggests the importance of measurement of the blood glucose level when the symptoms of stroke are first recognized.

Hypoglycaemic brain lesions in a dog with insulinoma

A 5-year-old female Collie dog showed excessive salivation, vomiting and neurological signs, including hind-limb weakness, mental dullness and subsequent recumbency with paddling movements of the limbs. Blood glucose and insulin concentrations were 35 mg/dl and 70.0 microU/ml, respectively. At necropsy, two masses, one at the caudal edge of the pancreas and the other in the omentum, were found and diagnosed as insulinoma. Histological examination of the brain showed early signs of acute neuronal necrosis exclusively in the superficial layers of the cerebral cortex, in addition to spongy changes in the dentate gyrus of the hippocampus. The light microscopical findings were identical in character and distribution with those of naturally occurring hypoglycaemia in humans and experimentally induced hypoglycaemia in animals.

Low frequency of adenylate kinase release into cerebrospinal fluid during balanced, normotensive anaesthesia and a non-orthognathic surgical procedure

Activity of strictly intracellular enzymes in the cerebrospinal fluid (CSF) may indicate leakage from dysfunctional brain cells. Increased activity of adenylate kinase (AK) in the CSF is indicative of brain cell injury arising from several sources, among them orthognathic surgery. The mechanism in the latter case is obscure, but the use of an oscillating saw which generates vibrations, and the site of surgery close to the brain may be contributing factors. Anaesthesia may also play a role. In the present study, CSF-AK activity was measured after hysterectomy and was compared with activity after orthognathic surgery in two other studies. Four of 19 patients (21%) in the present study expressed pathological activity, compared with 34 of 47 (72%) orthognathic patients in the two other studies. No firm conclusion may be drawn from historical comparisons, and the difference in activity seen between the two types of surgery might not necessarily be the result of surgical factors. Until this is investigated further, however, we conclude that there may be a difference in postoperative CSF-AK activity between orthognathic and lower abdominal surgery.