The unusual suspects: a curious case of acute kidney injury-Questions.

A previously healthy 8-year-old boy presented for evaluation of three weeks of daily fevers to 101 °F, myalgia, gingival swelling, mouth sores, blurry vision, and periorbital rash with new onset of dark urine. His family history was significant for rheumatologic disease without known renal involvement. Initial workup demonstrated mild anemia with hemoglobin of 10.9 g/dL, low reticulocyte count, few schistocytes on peripheral smear, thrombocytopenia with platelets of 8000/mm^3, albumin 2.5 g/dL, AST 2084 IU/L, ALT 787 IU/L, GGT 223 IU/L, creatine kinase of 10000 IU/L, ferritin of 4290 ng/mL, fibrinogen 191mg/dL, triglycerides 160mg/dL, and creatinine increased from a baseline of 0.45mg/dL to 1.0 mg/dL. Other inflammatory indices were negative and infectious diseases evaluation did not suggest an infectious etiology of his symptoms. Urinalysis showed 3+ blood and 3+ protein on dipstick. His initial urine and accompanying microscopy are pictured in Figure 1.