Spontaneous Cholesterol Embolism Presenting as Acute Kidney Injury: A Nephrology Approach and Literature Review.

Cholesterol crystal embolism (CCE) is an underdiagnosed systemic condition that often leads to acute kidney injury (AKI) with poor kidney prognosis. Herein, we report a case of dialysis-dependent AKI due to spontaneous CCE with early kidney recovery. A 76-year-old man with hypertension, diabetes mellitus type 2, chronic hepatitis B virus, adrenal insufficiency and gout presented with fatigue, polyarthritis, oliguria, and elevated serum creatinine. Imaging revealed an infrarenal abdominal aortic aneurysm with diffuse atherosclerosis, and laboratory findings showed markedly elevated D-dimer without eosinophilia or autoantibodies. Despite supportive measures, kidney function deteriorated rapidly, necessitating urgent initiation of intermittent hemodialysis on 4 occasions during the first week. Kidney biopsy confirmed cholesterol clefts within medium-sized arteries, establishing the diagnosis of CCE. The patient was treated with corticosteroids, high-dose statins, aspirin, and supportive therapy. Remarkably, kidney function improved, allowing discontinuation of dialysis by the end of the first week, and he was discharged on day 22 with significant recovery of kidney function. In conclusion, CCE-related AKI is rare and typically associated with poor outcomes, yet this case demonstrates that early recognition, timely kidney biopsy, and prompt initiation of corticosteroids and high-dose statins may enable full kidney recovery.