[Clinicopathological study of multiple myeloma associated with hyperammonemia]

Of 5 multiple myeloma patients with hyperammonemia, autopsy was performed in 4 patients, while amino acid metabolism was examined in 3 patients. As a result they were classified into the following 3 types; A, liver dysfunction and severe liver infiltration of myeloma cells. B, severe liver infiltration without liver dysfunction. C, Neither liver dysfunction nor severe liver infiltration. In one type A patient, isoleucine decreased. In two patients without liver dysfunction (one type C patient and another patient in whom autopsy was not performed) valine, leucine and isoleucine decreased, and tyrosine decreased slightly. The Fischer ratio decreased in these 2 patients, while it decreased slightly in a type A patient. Clinically, in 4 patients hyperammonemia was observed during periods of poor general condition and when refractory to chemotherapy. In an aggressive type case, consciousness disturbance was developed rapidly and multiple myeloma was diagnosed. In all patients, consciousness disturbance was noted. Hyperammonemia might have been caused by hepatic failure or systemic-portal shunt in patients with liver infiltration. In those without liver infiltration, it was suggested that hyperammonemia was caused by myeloma related humoral factors that influence amino acid metabolism.