Acute Kidney Injury, Anemia, and Recurrent Dark Red Urine

Abstract

Case Presentation A 50-year-old man presented to the emergency department reporting dark-colored urine and diffuse abdominal pain. He reported two similar episodes in the previous four months but did not seek medical attention. Additionally, a week before, he had a flu-like syndrome for which he took a nonsteroidal anti-inflammatory drug. The patient's medical history was notable only for uninvestigated chronic mild thrombocytopenia. Glomerular filtration rate was normal three months earlier (serum creatinine, 0.89 mg/dL). Physical examination findings were unremarkable, except for mucocutaneous pallor. Laboratory tests revealed serum creatinine level of 7.8 mg/dL, hemoglobin level of 6.1 mg/dL, and platelet count of 127 × 10 3 /μL. Urinalysis showed heme (3+) but was negative for protein on dipstick, with the microscopic examination showing rare blood cells without cellular casts. Peripheral-blood smear showed mildly reduced platelet count and rare schistocytes. Other relevant laboratory values are presented in Table 1.