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Go back to clinical information and images Diagnosis: Sickle cell nephropathy (with secondary focal segmental glomerulosclerosis) The renal manifestations of sickle cell disease (SCD) range from various functional abnormalities to gross anatomic alterations of the kidneys. The inner medulla’s relatively hypoxic, hypertonic, and acidotic environment is known to predispose to sickling of red blood cells, which significantly decreases renal medullary blood flow through vaso-occlusion. Depending on the predominant site of tubule involvement, clinical manifestations vary. Proximal tubule dysfunction generally impairs urinary concentration, while more distal tubule dysfunction may impair potassium excretion, leading to hyperkalemia (as seen in various forms of renal tubular acidosis) (Lerma EV. Renal manifestations of sickle Cell disease. In. eMedicine. [Link]). Glomerular enlargement, perihilar focal segmental glomerulosclerosis (FSGS), and hemosiderosis are commonly seen in patients with sickle cell nephropathy. Glomerular ischemia and secondary sclerosis lead to hyperfiltration and glomerular hypertrophy, which probably contributes to glomerulosclerosis. As glomerulosclerosis becomes more extensive, the GFR starts to decrease and nonselective proteinuria may result. Classic FSGS is characterized by glomerular hypertrophy, glomerular capillary hypertension, podocyte damage, and mesangial destruction. Variable degrees of tubular atrophy and interstitial fibrosis develop (Lerma EV. Renal manifestations of sickle Cell disease. In. eMedicine. [Link]). Lesions resembling those found in membranoproliferative glomerulonephritis (MPGN), with mesangial expansion and basement membrane duplication, have been described, either as an isolated finding or in association with focal sclerosis. However, unlike in idiopathic MPGN, these lesions are devoid of immune complexes and electron-dense deposits. Sickle cell disease patients with FSGS tend to progress to end-stage renal disease more rapidly than do patients with MPGN (Lerma EV. Renal manifestations of sickle Cell disease. In. eMedicine. [Link]). Proteinuria is a frequent finding in SCD, and is present in 30% of patients during long-term follow-up. Both proteinuria and renal insufficiency increase with age in a parallel pattern. Asymptomatic hematuria is considered to be one of the most prevalent features of sickle cell nephropathy. Additional pathologic processes that may involve the glomeruli include chronic tubulointerstitial nephritis secondary to analgesic-abuse nephropathy, which is common in persons with this condition. Go back to clinical information and images References
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