Bilateral Spontaneous Kidney Hemorrhage Presenting as Acute Anemia in Pyelonephritis and Newly Diagnosed Diabetes

Wunderlich syndrome is spontaneous, nontraumatic hemorrhage into the subcapsular, perirenal, or pararenal space.We describe a 34-year-old woman with no relevant medical history who presented with right flank pain, dysuria, fever, and chills and was diagnosed with acute right pyelonephritis complicated by sepsis, acute kidney injury, and newly diagnosed type 2 diabetes mellitus; thrombocytopenia was already present on admission.On hospital day 3, hemoglobin fell from 13.2 to 8.4 g/dL and platelets to 20,000/µL without overt bleeding or hemodynamic instability, while coagulation studies remained normal.Noncontrast computed tomography revealed bilateral subcapsular hematomas together with inflammatory change in both kidneys.Evaluation revealed no evidence of a neoplastic, vasculitic, or coagulopathic cause, and she was managed conservatively with transfusion, broad-spectrum antibiotics, and glycemic control.The hematomas regressed on serial imaging, and kidney function normalized without invasive intervention.Although symptoms localized to the right, imaging showed bilateral involvement, and thrombocytopenia preceded the hemorrhage.We hypothesize that sepsis-associated thrombocytopenia acted as a systemic factor that lowered the bleeding threshold, with diabetes as a plausible amplifying factor, although a single case cannot establish causation.An unexplained decline in hemoglobin during treatment of acute pyelonephritis should prompt cross-sectional imaging.