(736) Hyperlactatemia Associated With Acute Leukemia in a Child: A Case Report

Introduction: Lactic acidosis (LA) is a rare and unusual metabolic complication, particularly in pediatric hematological malignancies. Little is known about Type B LA in pediatric cancer despite its severity. Its mechanisms are poorly understood, with little evidence supporting various treatment options.

Description: We present a case of a 14-year-old boy with relapsed acute lymphoblastic leukemia admitted to the pediatric intensive care unit for the management of septic shock with hyperlactatemia. His initial labs were notable for gap metabolic acidosis with an anion gap of 21 mEq/L, pH of 7.08, serum bicarbonate of < 5 mmol/L, and elevated LA of 12.58 mmol/L. At presentation, he was in septic shock, but the hyperlactatemia persisted despite fluid resuscitation and improved hemodynamics. His renal function was appropriate at this time. The hyperlactatemia began to show a steady decline after the initiation of chemotherapy. In the interim, thiamine and bicarbonate therapies were tried with little benefit.

Discussion: Despite the fast-growing tendency of cancer cells, they use the primitive, inefficient mechanism of anaerobic glycolysis to generate the required amounts of energy. Therefore, a significant proportion of their glucose is converted to lactate. This is known as the Warburg phenomenon, where cancer cells derive fifty percent of their energy from cytosolic glycolysis even in the presence of adequate oxygenation, with the remainder of cell energy derived from the mitochondrial respiratory chain. The best treatment for patients with malignancies who develop Type B LA is unclear. Initiating aggressive chemotherapy has been effective in a small number of patients. Using bicarbonate as an exogenous buffer to correct the acidosis in Type B LA can be detrimental. However, this treatment may be necessary to prevent the adverse cardiovascular effects of elevated lactate concentration, especially in the hemodynamically unstable patient. Thus in pediatric patients with malignancies who are hemodynamically stable with an anion gap acidosis, the possibility of Type B LA should be entertained in differential diagnoses. Physicians need to be aware of this condition as LA associated with malignancy is reported to have a poor prognosis.