A Case of Proximal Renal Tubular Acidosis Accompanied by Vitamin D Deficient Rickets

Kwon, Seung-Yeon; Choi, Youn-Jung; Kim, Kee-Hyuck

J Korean Soc Pediatr Nephrol > Volume 10(1); 2006 > Article

J Korean Soc Pediatr Nephrol 2006;10(1): 58-64.

비타민 D 결핍성 구루병에 동반된 근위 신 세뇨관성 산증 1례

권승연, 최윤정, 김기혁

¹연세대학교 의과대학 소아과학교실
²연세대학교 의과대학 소아과학교실
³국민건강보험공단 일산병원 소아과

A Case of Proximal Renal Tubular Acidosis Accompanied by Vitamin D Deficient Rickets

Seung-Yeon Kwon, Youn-Jung Choi, Kee-Hyuck Kim

¹Department of Pediatrics, Yonsei University College of Medicine
²Department of Pediatrics, Yonsei University College of Medicine
³Department of Pediatrics, NHIC Ilsan Hospital

ABSTRACT

In the clinical state of vitamin D deficiency, it is possible that associated phosphate depletion, parathyroid hormone excess, and hypocalcemia may all depress the proximal tubular reabsorption of bicarbonate, in addition to abnormal skeletal modeling or remodeling, Although nutritional rickets is considered a rare disease in developed countries nowadays, cases of vitamin D deficient rickets caused by various unhealthy lifestyles such as insufficient exposure to sunlight, breast feeding infants without giving vitamin D supplements, unbalanced vegetarian diets of breast feeding mothers, low-birth weight, and maternal deficiency of vitamin D or calcium are increasing. Here, we present the case of an 8 month old girl, who was completely breastfed without any weaning diet or infant vitamin supplements. She visited our emergency room with hypocalcemic seizure and subsequently was diagnosed with vitamin D deficient rickets accompanied by overt bone changes and proximal renal lobular acidosis. After intravenous(IV) and oral calcium replacement therapy(IV calcium gluconate injection 1 mEq/kg/day for 6 days, 2 mEq/kg/day for 4 days followed by oral calcium gluconate administration 4 g/day for 3 days) with vitamin D supplement(Alfacalcidol 0.5 mcg/day) during admission, serum calcium level was normalized with clinical improvement. Oral sodium bicarbonate(0.6 g/day) was administered from the $2^{nd}$ hospital day for 2 weeks, which normalized the serum bicarbonate(measured by $tCO_2$) level. Calcium and vitamin D replacement were continued for 2 weeks and 3 months each. After discontinuing medications, follow up laboratory findings showed good maintenance of serum calcium, alkaline phosphate and bicarbonate levels with complete improvement of bone X-ray findings.

Key words: Vitamin D deficiency | Rickets | Renal tubular acidosis | Breast feeding