ⓘ Sickle cell nephropathy

                                     

ⓘ Sickle cell nephropathy

Sickle cell nephropathy is a type of nephropathy associated with sickle cell disease which causes kidney complications as a result of sickling of red blood cells in the small blood vessels. The hypertonic and relatively hypoxic environment of the renal medulla, coupled with the slow blood flow in the vasa recta, favors sickling of red blood cells, with resultant local infarction. Functional tubule defects in patients with sickle cell disease are likely the result of partial ischemic injury to the renal tubules.

Also sickle cell anemia in young patients is characterized by renal hyperperfusion, glomerular hypertrophy, and glomerular hyperfiltration. Many of these people eventually develop a glomerulopathy leading to glomerular proteinuria is present in up to 30%, and in some, the nephrotic syndrome. The joint inheritance of microdeletions in the -globin gene of thalassemia appear to protect against the development of nephropathy and are associated with lower mean arterial pressure and a lower content of protein in the urine.

A mild increase in the blood content of nitrogen and uric acid can also develop. Advanced kidney failure and high urea level in the blood observed in 10% of cases. Pathologic examination reveals the typical lesion of "hyperfiltration nephropathy," namely, focal segmental glomerulosclerosis. This discovery led to the suggestion that anemia-induced hyperfiltration in childhood is the main cause of the adult glomerulopathy. Loss of nephrons secondary to ischemic injury also contributes to the development of azotemia in these patients.

In addition to the glomerulopathy described above, renal complications of sickle cell anemia include cortical infarcts leading to loss of function, persistent hematuria, and perinephric hematomas. Papillary infarcts, confirmed radiologically in 50% of patients with sickle trait, lead to an increased risk of bacterial infection in the scarred renal tissues and functional tubule irregularities. The presence of visible blood in urine without pain, occurs with greater frequency in sickle trait than in sickle cell disease and likely results from infarctive episodes in the renal medulla. Functional tubule abnormalities such as nephrogenic diabetes insipidus a result of the significant reduction in Vase inscribed in blood flow, combined with ischemic tubule injury. This concentration defect places these patients at increased risk of dehydration and therefore the credit crises. The concentrating defect also occurs in individuals with sickle trait. Other tubule defects are associated with potassium and hydrogen ion excretion, occasionally leading to high blood potassium, metabolic acidosis and a defect in the excretion of uric acid, which, combined with increased synthesis of purine in bone marrow, which leads to a high concentration of uric acid in the blood.