Weakness, neuropathy, and coma following total parenteral nutrition in underfed or starved rats: relationship to blood hyperosmolarity and brain water loss.

The continuous infusion of a concentrated, high-caloric glucose solution intravenously into underfed or 3-day-starved rats at a rate of 390 kcal/kg/day results in hypophosphatemia, muscular weakness, neuropathy, lethargy, occasional convulsions, and eventual coma and death. This sequence of events is not observed in similarly infused normal rats. It is a model of a fatal parenteral nutrition syndrome which occurs in undernourished patients. Rats in coma had an eightfold increase in the blood glucose level, a 1.6-fold increase in serum osmolarity, a 16% to 20( decrease in brain water content, and normal blood ketones. A lag phase of at least 8 hr and often 12 to 24 hr occurred following the start of the hyperosmotic glucose infusion before the blood glucose began to accumulate progressively and the syndrome developed. The onset of the syndrome could be prevented by the administration of large amounts of insulin required to keep the blood sugar from exceeding 250 mg/dl. Thus the rat model of the fatal hyperalimentation syndrome is a form of hyperglycemic, hyperosmolar, nonketotic coma caused by brain dehydration.