Clinicopathological study of pigment induced nephropathy; a retrospective study

Introduction: Rhabdomyolysis and hemolysis cause pigment nephropathy that progresses to chronic kidney disease (CKD) requiring hemodialysis in some patients. As this is a significant financial burden, understanding the etiologies and renal biopsy findings aids in timely diagnosis and optimizing outcomes. Objectives: We analyzed the etiology, clinicopathological features, and renal outcome of seventeen patients with pigment nephropathy. Patients and Methods: This retrospective study was conducted from 2018 to 2021. Data on detailed clinical history, laboratory parameters, renal biopsy records and the renal outcome was collected. Results: Among seventeen patients with pigment nephropathy, the etiology was rhabdomyolysis in 15 patients and hemolysis in two patients. Oliguria was the most common clinical presentation, and all patients presented with acute kidney injury (AKI). Renal biopsy revealed reddish beaded granule and vermiform-like casts in 10, brownish casts with intra-tubular hemosiderin in three, and granular and calcific casts in two patients each. While fourteen patients recovered to normal renal function within three months, one progressed to stage 5 CKD, one had stage 2 CKD, and one died. Conclusion: In most patients, clinical history did not reveal a direct diagnosis of rhabdomyolysis, and hence one must remain vigilant even in the absence of the classical triad of symptoms.