Clinical profile and outcome of pigment-induced nephropathy

Background: Pigment nephropathy represents one of the most severe complications of rhabdomyolysis or hemolysis. Methods: We performed a retrospective observational study to analyze the etiology, clinical manifestation, laboratory profile and outcome in patients with biopsy-proven pigment-induced nephropathy between January 2011 and December 2016. History, clinical examination findings, laboratory investigations and outcome were recorded. Results: A total of 46 patients were included with mean follow-up of 14 +/- 5.5 months. Mean age was 40.15 +/- 12.3 years, 65% were males (male: female, 1.8:1) and similar to 37 (80.4%) had oliguria. Mean serum creatinine at presentation and peak creatinine were 7.5 +/- 2.2 and 12.1 +/- 4.3 mg/dL, respectively. Evidence of rhabdomyolysis was noted in 26 patients (64%) and hemolysis in 20 patients (36%). Etiology of rhabdomyolysis include snake envenomation (10 patients), seizures (7), strenuous exercise (5), wasp sting (2) and rifampicin induced (2). The causes of hemolysis include rifampicin induced (7 patients), sepsis (5), malaria (3), mismatched blood transfusion/transfusion reaction (3) and paroxysmal nocturnal hemoglobinuria (2). On renal biopsy, two patients had acute interstitial nephritis and two had immunoglobulin A deposits in addition to pigment nephropathy. All except one (97.8%) required hemodialysis (HD) during hospital stay and mean number of HD sessions was 9 +/- 2. A total of three patients with sepsis/disseminated intravascular coagulation died, all had associated hemolysis. On statistical analysis, there was no difference between AKI due to rhabdomyolysis and hemolysis except for high creatine phosphokinase in patients with rhabdomyolysis and Lactate dehydrogenase level in patients with hemolysis. At mean follow-up, five patients (12%) progressed to chronic kidney disease (CKD). Conclusions: Pigment nephropathy due to rhabdomyolysis and hemolysis is an important cause of renal failure requiring HD. The prognosis was relatively good and depends on the etiology; however, long-term studies and follow-up are needed to assess the true incidence of CKD due to pigment nephropathy.