From the Research
Clinical Manifestations of Sickle Cell Nephropathy
The clinical manifestations of Sickle Cell (SC) nephropathy include:
- Renal acidification defect
- Distal nephron dysfunction
- Renal papillary necrosis
- Proteinuria related to glomerular injury, leading to end-stage renal disease 1, 2
- Impairment of urinary concentrating ability, which is a problem caused by the destruction of the renal medulla that initiates in childhood 1, 3
- Defect in urine acidification 2
- Haematuria and increased risks of urinary tract infections and renal medullary carcinoma 3
- Chronic kidney disease (CKD) and acute kidney injury 4, 3
Age-Related Manifestations
The presence of proteinuria in SCD is age-related and starts as microalbuminuria in adolescence and progresses to macroalbuminuria 1. Albuminuria and inability to concentrate the urine precede the onset of renal failure, and, along with other tubular dysfunctions, are early warning signs of sickle cell nephropathy (SCN) 4.
Underlying Mechanisms
Renal involvement in SCD is usually more severe in homozygous disease (sickle cell anaemia, HbSS) than in compound heterozygous types of SCD (for example HbSC and HbSβ(+)-thalassaemia), and is typically mild, albeit prevalent, in the heterozygous state (sickle cell trait, HbAS) 3. Endothelial dysfunction related to chronic hemolysis and the relative renal hypoxia caused by vaso-occlusive sickle red blood cells are probably two key factors for SCN development 2.