Acute renal failure with severe loin pain and patchy renal ischemia after anaerobic exercise in patients with or without renal hypouricemia

Acute renal failure induced by rhabdomyolysis after strenuous exercise is well known. We describe here a new type of acute renal failure with severe loin pain which develops after anaerobic exercise (ALPE), for example, 200-meter track racing. The patients complained of severe loin pain several hours after exercise and presented at the emergency room. Since our first description 118 cases have been reported. The serum creatinine concentration was 4.7 +/- 2.9 mg/dl (mean +/- SD) at the initial examination and 6.0 +/- 3.0 mg/dl at maximum. Forty-nine of 96 cases whose serum uric acid levels were described revealed renal hypouricemia (51.0%). A specific risk factor is suggested by the fact that acute renal failure recurred after exercise in 20 of 118 cases. The creatine phosphokinase and serum myoglobin concentrations were normal or only slightly elevated, suggesting damaged type 2 muscle fibers. Renal computed tomography scans, performed several hours to 1-2 days after contrast medium administration, revealed multiple wedge-shaped areas of contrast enhancement. Forty-six of 50 cases examined by delayed computed tomography scan revealed bilateral wedge-shaped contrast enhancement. Although less efficient, radioisotopic scans, such as a methylene diphosphonate bone scan, have also been employed to detect patchy accumulation of isotopes in the kidneys (12 of 19 cases). The pathogenesis of ALPE may be patchy vasoconstriction of the renal vessels, because of its wedge-shaped distribution and its reversibility. Such vascular spasm would account for the renal pain. The prognosis was good, although 20 of 109 cases required dialysis treatment. In conclusion, there are two types of exercise-induced acute renal failure: one is the well-known myoglobin-induced acute renal failure, and the other is ALPE that may be nonmyoglobin induced or induced by myolysis of type 2 muscle fibers due to anaerobic exercise. One hundred and eighteen cases of ALPE were collected from the literature, and half of the cases were found to display renal hypouricemia.