Shiga toxin-associated hemolytic uremic syndrome

A 78-year-old Japanese woman was admitted to our hospital with complaints of right lower abdominal pain and bloody diarrhea. The patient ate undercooked beef 4 days before the onset. Right lower abdominal tenderness was revealed on palpation, and the remaining physical examination was unremarkable. Initial laboratory test results were as follows: white blood cell count 9,000 /µL (normal range 3,300-8,600 /µL), hemoglobin 12.3 g/dL (normal range 11.6-14.8 g/dL), lactate dehydrogenase 288 U/L (normal range 124-222 U/L), and serum creatinine level 1.35 mg/dL (normal range 0.49-0.79 mg/dL). Other laboratory tests, including platelet count and serum biochemistry, were unremarkable. Computed tomography showed a thickened wall of the cecum, ascending colon, and proximal transverse colon (Figure 1A). Colonoscopy revealed marked edema and hemorrhagic mucosa in the cecum and ascending colon (Figure 1B). The stool culture was positive for Shiga toxin-producing Escherichia coli (STEC): O157. Five days following the initiation of supportive therapy, abdominal tenderness and bloody diarrhea resolved. However, laboratory tests showed features of hemolytic uremic syndrome (HUS): thrombocytopenia (platelet count, 43,000 /μL [normal range 158,000-348,000 /μL]), acute kidney injury (creatinine, 1.89 mg/dL), and hemolytic anemia (hemoglobin, 8.6 g/dL; lactate dehydrogenase, 600 U/L; haptoglobin, <10 mg/dL [normal range 66-218 mg/dL]). A peripheral blood smear showed the presence of schistocytes (Fig. 1C, arrows). Shiga toxin-associated HUS (STEC-HUS) was diagnosed. Her urine output decreased to less than 400 mL/day and her serum creatinine increased to 2.5 mg/dL; therefore, she received continuous hemodialysis as renal replacement therapy. After 18 days of hemodialysis, her renal function improved (creatinine 1.02 mg/dL) and she was discharged on hospital day 51.