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Parathyroid function tests with EDTA infusions in infancy and childhood
Insights
EDTA infusions can help assess parathyroid gland function in children. This method aids in identifying hyperparathyroidism, hypoparathyroidism, and other calcium and phosphorus metabolism disorders.
Area of Science:
- Pediatric Endocrinology
- Mineral Metabolism
Background:
- Parathyroid hormone (PTH) regulates calcium and phosphorus levels.
- Assessing parathyroid gland function is crucial for diagnosing metabolic disorders in children.
Purpose of the Study:
- To evaluate the utility of ethylenediaminetetraacetic acid (EDTA) infusions in determining parathyroid gland function in pediatric and adult subjects.
- To correlate parathyroid hormone (PTH) response with renal tubular reabsorption of phosphate and urinary cyclic AMP excretion.
Main Methods:
- Administered 17 EDTA infusions to 11 children and 2 adults.
- Monitored serum ionized calcium, PTH levels, renal tubular reabsorption of phosphate, and urinary cyclic AMP excretion before and after EDTA infusion.
Main Results:
- Serum ionized calcium decreased significantly post-EDTA infusion.
- Excessive PTH responses were observed in subjects with active hypophosphatemic rickets.
- Low or undetectable PTH responses were noted in subjects with hypercalcemia-related issues.
- Normal PTH responses were seen in specific cases, including post-tetany correction and malabsorption syndrome.
- Renal tubular reabsorption of phosphate showed an inverse relationship, while urinary cyclic AMP excretion showed a positive relationship with PTH response.
Conclusions:
- EDTA infusion is a potentially valuable tool for identifying hyper-, normo-, and hypoparathyroid states in infants and children.
- This method can help define the functional status of parathyroid glands in pediatric patients with disordered calcium and phosphorus metabolism.
Abstract:
To determine the functional capabilities of the parathyroid glands, 17 EDTA infusions were given to 11 children (ages 1 month to 12 years) and to two mothers of four of the children. Serum ionized Ca fell from 4.1 mg/dl to 3.4 mg/dl. Excessive parathyroid hormone responses were elicited during seven of nine EDTA infusions in five children and in one adult with hypophosphatemic rickets, during the active phase of rickets. In four of five subjects with problems related to hypercalcemia, borderline low or undetectable PTH responses were elicited. Three relatively normal PTH responses were obtained, two in an infant after phosphate-induced hypocalcemic tetany was corrected, and one in a child with a malabsorption syndrome. The renal tubular reabsorption of phosphate was inversely related and the urinary cyclic AMP excretion was positively related to the PTH response. Thus EDTA infusions in infants and children might be useful in the identification of hyper-, normo-, or hypoparathyroid states and would be of value in defining the functional condition of the parathyroid glands in children with deranged Ca or P metabolism.