Risk factors:
(1) maternal diabetes
(2) maternal hyperparathyroidism
(3) maternal vitamin D deficiency
(4) prematurity
(5) intrauterine growth retardation
(6) prolonged delivery, anoxia and/or asphyxia
(7) familial hypoparathyroidism
Clinical manifestations:
(1) onset during the first 72 hours after birth
(2) convulsions
(3) ECG changes (prolonged QT interval, conduction abnormalities)
(4) tetany
(5) transient course
Laboratory testing:
(1) low serum calcium. The ionized serum calcium may be more reliable indicator than the total serum calcium.
(2) low serum parathyroid hormone (PTH) levels
(3) The infant should be screened for hypomagnesemia, especially if the hypocalcemia does not respond as expected to conventional therapy.
Differential diagnosis:
(1) rickets of prematurity (see Chapter 20)
