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

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

• Kwon SY
• Choi YJ
• Kim KH

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 tubular 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 2nd hospital day for 2 weeks, which normalized the serum bicarbonate(measured by tCO2) 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.

Keyword

Vitamin D deficiency; Rickets; Renal tubular acidosis; Breast feeding

MeSH Terms

Acidosis, Renal Tubular*
Breast Feeding
Calcium
Calcium Gluconate
Developed Countries
Diet
Diet, Vegetarian
Emergency Service, Hospital
Female
Follow-Up Studies
Humans
Hypocalcemia
Infant
Life Style
Mothers
Parathyroid Hormone
Rare Diseases
Rickets*
Seizures
Sodium
Sunlight
Vitamin D Deficiency
Vitamin D*
Vitamins*
Weaning
Calcium
Calcium Gluconate
Parathyroid Hormone
Sodium
Vitamin D
Vitamins