RESUMEN
BACKGROUND: Malignant lactic acidosis is a potentially overlooked but life-threatening complication in patients with haematological malignancies. The aim of this study is to describe the features of six patients with malignant lactic acidosis and to discuss how its initial presentation can be differentiated from that of severe sepsis. METHODS: We prospectively collected data of all consecutive patients with haematological malignancies, admitted to the Ghent University Hospital Intensive Care Unit (ICU) between 2000 and 2007. RESULTS: Of 372 patients with haematological malignancies admitted to the ICU for life- threatening complications, 58 presented with lactic acid levels > or = 5 mmol/L. Six were diagnosed with malignant lactic acidosis. All patients with malignant lactic acidosis had high-grade lymphoblastic malignancies and were referred with a tentative diagnosis of severe sepsis or septic shock; lactic acid levels exceeded 9.45 mmol/L and lactate dehydrogenase (LDH) levels were at least 1785 U/L. Two patients had hypoglycaemia. All had a pronounced polypnea. In all patients hepatic malignant involvement was suspected. Two of the six patients survived their episode thanks to the early recognition of malignant lactic acidosis and the prompt administration of chemotherapy. One patient was still alive 6 months after initiating chemotherapy. CONCLUSION: Malignant lactic acidosis is a rare and often rapidly fatal metabolic complication if not promptly recognized and treated. An elevated lactic acid concentration, in disproportion with the level of tissue hypoxia, together with high serum LDH are cornerstones in the diagnosis. In contrast to septic shock patients, pronounced polypnea (Kussmaul's breathing pattern) rather than the haemodynamic instability is prominent.
