Studies in ammonia metabolism: I. Ammonia metabolism and glutamate therapy in hepatic coma

Abstract

1. 1. Blood ammonia concentrations have been studied in a series of thirty-one patients in forty-four episodes of hepatic coma. Blood ammonia elevation has been found in 90 per cent of these patients. The clinical course of coma has in general been reflected in the degree of ammonia elevation. 2. 2. In a number of cases the appearance of hepatic coma did not coincide with elevation of blood ammonia. Occasionally, typical hepatic coma was accompanied by persistently normal blood ammonia concentrations, while in other instances a markedly elevated ammonia level was not accompanied by any neurologic deficit. The significance of these findings is discussed. 3. 3. It is suggested that at least two types of hepatic coma may occur. The first is precipitated by administration of exogenous ammonium salt or protein, is invariably associated with high blood ammonium levels and responds promptly to glutamate therapy. This is pure ammonia intoxication. The second type of coma occurs spontaneously during progressive hepatic failure, usually but not invariably is accompanied by elevated peripheral blood ammonia concentrations, and seldom is benefited by glutamate therapy.