Papillary infarcts, demonstrable radiographically in 50% of patients with sickle trait, lead to an increased risk of bacterial infection in the scarred kidney tissues and functional tubule abnormalities. Other complications include end stage renal disease (ESRD), medullary carcinoma, nephritic syndrome due to concurrent HPV B19 infection (this infection can cause benign self-limiting red cell aplasia). Risk Factors
Genetic
When looking at SCN, the main contributors leading to either a decrease or increase in CKD progression are the type of hemoglobin inheritance, myosin heavy chain 9, and apolipoprotein L1 genes. In those with the HbSS or HbSβ0 (no normal hemoglobin), they exhibit more severe forms of renal dysfunction at a high occurrence rate compared to those with HbSS or HbSβ+ (reduced number of normal hemoglobin). This ties in with the fetal hemoglobin levels (HbF) in that HbF levels are directly proportional to renal protection, and it has been found that in those with HbSS, a greater than 20% elevation in HbF led to no significant loss in renal function. Alpha-thalassemia has also been found to decrease HbS levels where the co-inheritance of alpha gene deletions reduce red blood cells and hemolysis. This inheritance has been shown to protect against hyposthenuria but the effect on other symptoms are unknown. Specifically in the African American population, the inheritance of an S trait and/or a C trait increases the risk of developing ESRD. For myosin heavy chain 9, and apolipoprotein L1, polymorphisms in these genes can contribute to worsening proteinuria but are not specific towards SCD.
An overriding aorta is a congenital heart defect where the aorta is positioned directly over a ventricular septal defect (VSD), instead of over the left ventricle. The result is that the aorta receives some blood from the right ventricle, causing mixing of oxygenated and deoxygenated blood, and thereby reducing the amount of oxygen delivered to the tissues. It is one of the four findings in the classic tetralogy of Fallot. The other three findings are right ventricular outflow tract (RVOT) obstruction (most often subpulmonary stenosis), right ventricular hypertrophy (RVH), and ventricular septal defect (VSD). References


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