Renal complications of sickle cell anemia in Zaria, Nigeria: An ultrasonographic assessment

Abstract

Background: Vaso-occlusion in the kidney is a capillary phenomenon. Renal medullary hyperosmolalrity and low oxygen tension encourage the maximum formation of sickled red cells. In addition, the glomerular loops constitute an aggregating point for the sickled red cells with subsequent obstruction to the blood flow. These factors, together with the large volume of blood flowing through the kidneys make renal complications inevitable in sickle cell anemia (SCA). Aim: The purpose of this prospective study was to report the renal sonographic findings of a sample of patients with hemoglobin electrophoretic pattern consistent with sickle cell anemia Materials and Methods: A cross-sectional prospective study of 74 patients with the diagnosis of SCA, as documented by electrophoresis and who attended the adult sickle cell clinic, Hematology Department of the Ahmadu Bello University Teaching Hospital, Zaria, Nigeria and 20 age-matched controls with a normal hemoglobin (HbAA) phenotype and with no history of renal disease, was carried out between April and December, 2010. None of the patients had any clinical evidence of acute sickle episode (crisis) at the time of ultrasonographic examination. B-mode ultrasonography with Aloka SSD-3500 was used to assess the kidneys. The hematological parameters were determined by multiparameter analyzer Sysmex XT 2000i, whereas creatinine and urea of the patients were also analyzed using the Selectra XL chemistry autoanalyzer. Results: Renal size of the study group was compared with that of the control group and it showed a significant increase in the adult patients with SCA (P<0.05). The mean right renal length in the study group and control group was 10.65±0.97 cm and 9.95±0.80 cm (P<0.001), respectively, whereas the mean left renal length in the study group and control group was 10.70±1.02 cm and 10.00±0.66 cm (P<0.001), respectively. Statistical relationships between renal length and some hematological indices (packed cell volume (PCV), red blood cell count, and reticulocyte count) showed no correlation but renal length was positively correlated with reticulocyte count, especially high reticulocyte count. Other findings documented and discussed include echogenicity of renal parenchyma, hydronephrosis, and papillary necrosis. Conclusion: Renal ultrasound imaging of patients with SCA showed a high incidence of renal abnormalities.