LAUSR

Acute renal failure (ARF) with severe loin pain and patchy renal vasoconstriction is a rare syndrome described as an anaerobic exercise-induced acute kidney injury (AKI) without rhabdomyolysis. The characteristic computed tomography (CT) finding is multiple patchy wedge-shaped delayed contrast enhancement in the kidney. The syndrome is named as a clinical syndrome of ARF with severe loin pain after anaerobic exercise (ALPE). A 16-year-old Japanese boy was admitted to our hospital for vomiting and severe loin pain after Japanese fencing. He had kidney dysfunction with slightly increased serum creatine phosphokinase and was eventually diagnosed with ALPE based on the characteristic finding on delayed renal CT scans. He had no predisposing factors for ALPE, such as renal hypouricemia or analgesic use prior to the exercise; however, he had pigmenturia at the onset, which is an unusual finding for ALPE. The pigmenturia proved to be hemoglobinuria due to intravascular hemolysis, indicated by increased serum levels of indirect bilirubin and lactate dehydrogenase, an undetectable level of serum haptoglobin, and absence of red blood cells and myoglobin in the urine. The hemolysis following strenuous steps on a hard floor suggested that the phenomenon was march hemoglobinuria. Our patient is the first reported example in which ALPE developed in the setting of hemoglobinuria due to mechanical intravascular hemolysis.