Clinical Characteristics of Symptomatic Hypocalcemic Infants

Song, Joon Young; Shin, Young Lim; Yoo, Han Wook

Abstract

PURPOSE: The purpose of this study was to evaluate clinical manifestation, etiology and prognosis of hypocalcemic infants who were admitted with seizure.
METHODS
We reviewed medical records of 32 infants admitted at the Asan Medical Center with hypocalcemic seizure retrospectively. We classified patients into vitamin D deficiency group(n=7, 21.9%), transient hypoparathyroidism group(n=4, 12.5%), relative hypoparathyroidism with hyperphosphatemia group(n=16, 50%), and others(n=5, 15.6%) according to the laboratory results.
RESULTS
Of the 32 patients, 29 patients were improved. There were no differences in gestational age and birth weight among the three groups. In the vitamin D deficiency group, age of onset was later than those of the transient hypoparathyroidism group and relative hypoparathyroidism with hyperphosphatemia group(51.6+/-2.7 vs 8.3+/-.5, 8.2+/-.6 days). In the age when all laboratory results were normalized, transient hypoparathyroidism group was younger than those of vitamin D deficiency group and relative hypoparathyroidism group(33.2+/-4.6 vs 93.6+/-8.5, 77.1+/-2.4 days). In the total treatment period, relative hypoparathyroidism with hyperphosphatemia group was longer than those of vitamin D deficiency group and transient hypoparathyroidism group(68.9+/-3.5 vs 42.0+/-5.0, 25.0+/-4.3 days). Others included two 22q11.2 deletion syndrome patients, a congenital hypoparathyroidism, a pseudohypoparathyroidism, and an early neonatal hypocalcemia.
CONCLUSION
Transient hypoparathyroidism and hyperphosphatemia were major causes of neonatal hypocalcemia. And high calcitonin and peripheral organ resistance to parathyroid hormone act on hypocalcemia. In infants after one month, vitamin D deficiency was also an important cause of hypocalcemia. Most of the patients were improved within 1-2 months after proper management, but relative hypoparathyroidism with hyperphosphatemia group needed longer treatment. So, it is necessary to perform a systematic study for several complex causes that explain above fact.