All issues > Volume 45(3); 2002

Case Report

J Korean Pediatr Soc. 2002;45(3):413-417. Published online March 15, 2002.

Two Cases of Gitelman's Syndrome Diagnosed by Renal Clearance Study

Tae Hwa TH Kim¹, Seung Jun SJ Kim¹, Yu Kyung YK Seo¹, Jung-Yeon JY Shim¹, Hye Lim HL Jung¹, Moon Soo MS Park¹, Dong Hyuk DH Kum¹

¹Department of Pediatrics, Sungkyunkwan University, School of Medicine, Seoul, Korea

Correspondence Moon Soo MS Park ,Email: parkms@kbsmc.co.kr

Abstract

Gitelman's syndrome is an autosomal recessive disorder characterized by hypokalemic metabolic alkalosis, hypomagnesemia, and hypocalciuria that has recently been reported to be linked to thiazide-sensitive Na-Cl cotransporter gene mutation. In this study, we performed renal clearance studies to differentiate Gitelman's from Bartter's syndrome and to confirm the diagnosis in two patients clinically diagnosed with Gitelman's syndrome. Each patient was hydrated by 20 mL/kg body weight of oral water within 30 minutes, which was followed by intravenous half saline. When urinary flow reached 10 mL/min, samples of urine and serum were obtained to calculate the osmolar clearance, free water clearance, chloride clearance, and distal fractional chloride reabsorption. Subsequently, furosemide or hydrochlorothiazide was administered. Samples were collected and the same parameters were calculated. In our patients, chloride clearance was increased more than 10 times after furosemide administration(2.1 : 25.7 and 2.2 : 27.4 mL/min/100 mL GFR), but not increased after hydrochlorothiazide treatment(2.1 : 1.6 and 2.2 : 2.6 mL/min/100 mL GFR). And the distal fractional chloride reabsorption was significantly decreased by furosemide injection (73% : 15% and 75% : 4.6%), whereas hydrochlorothiazide had no effect on it(73% : 63% and 75% : 78%). These findings indicate that our patients have a defect in thiazide-sensitive Na-Cl cotransporter in the distal tubule, which is compatible with the pathophysiology of Gitelman's syndrome.

Keywords :Gitelman's syndrome, Renal Clearance Study