Parathyroid Hormone Deficiency, Neonatal

Two types:

1. Early neonatal hypocalcemia (DOL #1-4)
2. Late neonatal hypocalcemia (DOL #5-10)
   • True congenital hypoparathyroidism
   • Transient hypoparathyroidism
   • Phosphorous overload
   • Low Magnesium

Early Neonatal Hypocalcemia

• PTH level normally fall in the first 1-4 days of life
• This represents an exaggeration of this drop, as well as perhaps decreased calcium intake
• Often occurs in premature and sick newborns and in IDM
• Bottom Line: usually due to immature parathyroid gland

Late Neonatal Hypocalcemia

• Occurs between 5-10 days old, in healthy newborns, or later depending on degree of deficit
  • True primary hypoparathyroidism from DiGeorge, or other congenital absence of the glands.
  • Multiple syndromic and non-syndromic forms of PTH mutations with various inheritance patterns
  • Transient hypoparathyroidism from maternal hypercalcemia/ hyperparathyroidism (check mother’s calcium, phosphorous, and PTH level as part of eval of neonatal hypocalcemiaif diagnosis unclear)
  • Phosphorous overload (drinking regular cow’s milk that contains 6x more phosphorous than formula/breastmilk); more common in developing countries
  • Hypomagnesemia from colitis, or malabsorption

CHLA Board Review 2005