An update on sickle cell nephropathy.

Sickle cell disease (SCD) is a major health problem in many countries. Sickle cell nephropathy (SCN) is now a well-characterized entity with specific manifestations, risk factors and prognosis. The presence of sickled erythrocytes in the renal medullary vessels is the hallmark of the disease with a variety of renal complications. Renal manifestations of SCD include renal ischemia, microinfarcts, renal papillary necrosis and renal tubular abnormalities with variable clinical presentations. Proximal tubule dysfunction generally impairs urinary concentration, while more distal tubule dysfunction may impair potassium excretion, leading to hyperkalemia. Glomerular disease with proteinuria may develop due to ischemia and results in a compensatory increase in the renal blood flow and glomerular filtration rate; such hyperfiltration, combined with glomerular hypertrophy, probably contributes to glomerulosclerosis. Acute and chronic kidney disease are the expected outcomes of the disease. Both dialysis and kidney transplantation are effective renal replacement therapies for end-stage renal disease due to SCN, with a higher advantage for transplantation. Whether bone marrow transplantation in the early stage of the disease can halt the progression of SCN is unknown and awaits clinical studies.