Post-Graduation Program in Medical Sciences, Department of Internal Medicine, School of Medicine, Federal University of Ceará Fortaleza, Ceará Brazil.
Kidney Blood Press Res. 2013;38(1):1-10. doi: 10.1159/000355748. Epub 2014 Jan 28.
BACKGROUND/AIMS: Kidney abnormalities are one of the main chronic complications of sickle cell disease (SCD). The aim of this study is to investigate the occurrence of renal tubular abnormalities among patients with SCD.
This is a prospective study with 26 SCD adult patients in Brazil. Urinary acidification and concentration tests were performed using calcium chloride (CaCl2), after a 12h period of water and food deprivation. Fractional excretion of sodium (FENa), transtubular potassium gradient (TTKG) and solute free water reabsorption (TcH2O) were calculated. The SCD group was compared to a group of 15 healthy volunteers (control group).
Patient`s average age and gender were similar to controls. Urinary acidification deficit was found in 10 SCD patients (38.4%), who presented urinary pH >5.3 after CaCl2 test. Urinary osmolality was significantly lower in SCD patients (355 ± 60 vs. 818 ± 202 mOsm/kg, p=0.0001, after 12h period water deprivation). Urinary concentration deficit was found in all SCD patients (100%). FENa was higher among SCD patients (0.75 ± 0.3 vs. 0.55 ± 0.2%, p=0.02). The TTKG was higher in SCD patients (5.5 ± 2.5 vs. 3.0 ± 1.5, p=0.001), and TcH2O was lower (0.22 ± 0.3 vs. 1.1 ± 0.3L/day, p=0.0001).
SCD is associated with important kidney dysfunction. The main abnormalities found were urinary concentrating and incomplete distal acidification defect. There was also an increase in the potassium transport and decrease in water reabsorption, evidencing the occurrence of distal tubular dysfunction. .
背景/目的：肾脏异常是镰状细胞病（SCD）的主要慢性并发症之一。本研究旨在调查 SCD 患者肾小管异常的发生情况。
这是一项在巴西进行的 26 例 SCD 成年患者的前瞻性研究。在禁食水 12h 后，使用氯化钙（CaCl2）进行尿液酸化和浓缩试验。计算钠的分数排泄（FENa）、跨小管钾梯度（TTKG）和溶质自由水重吸收（TcH2O）。将 SCD 组与 15 名健康志愿者（对照组）进行比较。
患者的平均年龄和性别与对照组相似。10 例 SCD 患者（38.4%）存在尿酸化缺陷，在 CaCl2 试验后尿 pH 值>5.3。SCD 患者的尿渗透压明显较低（355±60 比 818±202 mOsm/kg，p=0.0001，禁食水 12h 后）。所有 SCD 患者均存在尿浓缩缺陷（100%）。SCD 患者的 FENa 较高（0.75±0.3 比 0.55±0.2%，p=0.02）。SCD 患者的 TTKG 较高（5.5±2.5 比 3.0±1.5，p=0.001），TcH2O 较低（0.22±0.3 比 1.1±0.3L/天，p=0.0001）。
SCD 与重要的肾功能障碍有关。发现的主要异常是尿浓缩和不完全远端酸化缺陷。还存在钾转运增加和水重吸收减少，表明存在远端肾小管功能障碍。
