Fructose-induced hyperlactemia in hyperosmolar syndromes.

Severe hyperlactemia of 8.7, 8.6 and 7.9 mmol/l, respectively, developed in three patients with hyperosmolar syndromes (two hypernatremic, 417 and 415 mosmol/kg H2O; one hyperglycemic 437 mosmol/kg H2O) during rehydration treatment with 5% fructose in water (fructose dosage 0.5 g/kg body wt. per hour). After resolution of the electrolyte disturbances, the infusion of fructose at the same dosage increased the plasma lactate concentration in two of the patients to 4.9 and 4.0 mmol/l, indicating near normalization of hepatic lactate utilization. Thus, in addition to peripheral insulin resistance and decreased muscular glucose utilization, the hyperosmolar state is associated with a reduced tolerance to fructose. This is most likely due to an osmolality-dependent impairment of hepatic gluconeogenesis. In rehydration therapy for hyperosmolar syndromes, fructose-containing infusion solutions should no longer be used.