The kidney in sickle cell disease

Today, one of my colleagues presented an interesting case of sickle cell disease with microscopic hematuria, nephrotic range proteinuria and elevated serum creatinine. The renal manifestations of sickle cell disease are myriad. There is a nice review article published last year on this topic (Scheinman, Nature Reviews Nephrology 2009). Common renal manifestations of sickle cell disease include:
- Painless microscopic or gross hematuria as a result of RBC sickling in vasa recta in relatively hypoxic renal medulla. More severe ischemia due to vaso-occlusive phenomena in vasa recta can lead to renal papillary necrosis.
- Tubular function defects like hypoesthenuria/impaired concentrating ability (because of involvement of juxtamedually nephron collecting ducts), incomplete distal RTA with hyperkalemia (because of voltage defect), supranormal proximal tubular function in initial stages causing increased sodium & phosphrous reabsorption and increased creatinine/uric acid secretion (?? because of prostaglandins)
- Sickle cell glomerulopathy with nephrosis more common than nephritis. Most common pathological diagnosis is FSGS predominantly involving juxta medually nephrons that are perfused by vasa recta. Medullary fibrosis is prominent.
Other key points:
- Lower incidence of hypertension
- More prone to acute renal failure (In addition to usual causes, keep in mind the renal vein thrombosis and urinary tract obstruction from blood clots)
- Renal medullary carcinoma: rare but exclusive to sickle cell patients
- For ESRD, transplant outcomes are not as good as for other ESRD patients