Hemolytic uremic syndrome without hemolytic anemia: a case report

Hemolytic uremic syndrome (HUS) is characterized by microangiopathic hemolytic anemia, thrombocytopenia and acute renal failure. Most cases of HUS are caused by E. coli O157:H7 verotoxin. In the case reported here, diarrhea continued for twenty days after an E. coli 0157:H7 infection and was followed by acute renal failure and thrombocytopenia. Examination of percutaneous renal biopsy tissue showed typical HUS findings, e.g., mesangiolysis in glomeruli and thickening of capillary walls with prominent double outlines, but there was no indication of hemolytic anemia. LDH and haptoglobin, indications of hemolytic anemia, were in the normal range throughout the patient's clinical course. The patient's red blood cells had P1 antigen, which reportedly provides protection by adsorption of toxin into the red blood cells thereby preventing or limiting toxic damage to other organs. Therefore, we assumed that because of the expression of P1 antigen in this patient, the kidneys were not severely damaged and microangiopathic hemolytic anemia was thereby avoided.