Renal hemosiderosis secondary to intravascular hemolysis after mitral valve repair: A case report

RATIONALE: Renal hemosiderosis is a disease in which hemosiderin deposits in the renal cortex as a form of iron overload. However, cases of renal hemosiderosis due to intravascular hemolysis following mitral valve repair have been rarely reported. PATIENT CONCERNS: We present the case of a 62-year-old woman who developed asymptomatic urinary abnormalities including microscopic hematuria and proteinuria due to renal hemosiderosis following a mitral valve repair surgery performed two years earlier. DIAGNOSES: A percutaneous renal biopsy showed no specific glomerular abnormality, tubular atrophy, or interstitial fibrosis but extensive deposition of hemosiderin in the proximal tubule. The patient was diagnosed with renal hemosiderosis and chronic intravascular hemolysis following mitral valve repair. INTERVENTIONS: Our patient refused a mitral valve repeat surgery and hence was treated with oral iron preparations, N-acetylcysteine, and a β-receptor blocker. OUTCOMES: Moderate mitral regurgitation with the regurgitant blood striking against the annuloplasty ring was confirmed on follow-up echocardiography. After the 24-month follow-up period, hemolytic anemia persisted, but there was no significant decline of renal function. LESSONS: For cases of chronic intravascular hemolysis accompanied with asymptomatic urinary abnormalities, a renal biopsy is required to exclude underlying kidney pathology and predict potential renal insufficiency.