A Case of Type B Lactic Acidosis in Multiple Myeloma

Introduction Type B lactic acidosis is rare in patients with malignancies. We report a case of a 58-year-old man who was admitted for dyspnea, and was found to have severe lactic acidosis from relapsed multiple myeloma (MM). The degree of lactic acidosis transiently improved with chemotherapy and hemodialysis and worsened when therapies were withdrawn. We also present a brief review of literature on type B lactic acidosis occurring with MM and its proposed mechanisms. This case highlights the importance of recognizing lactic acidosis as a manifestation of an aggressively relapsing hematologic malignancy. Type A lactic acidosis occurs secondary to tissue hypoxia and anaerobic metabolism, whereas type B lactic acidosis is a rare condition related to underlying diseases, errors in metabolism, medications, or intoxication. Review of published cases documents that most cases f type B lactic acidosis were associated with hematological maligancies, predominantly lymphomas (Table 1). There have only been 2 reported cases of type B lactic acidosis-associated MM.