Hypocalcaemia Flashcards
When does the majority of fetal calcium accretion occur?
During the third trimester.
What happens to calcium levels within 24 hours after abrupt placental transfer?
They drop.
How long does it take for calcium levels to reach levels in older children after the drop?
Two weeks.
Why may the measurement of total calcium be misleading?
In states of low albumin.
What may happen to total calcium levels in states of low albumin despite normal ionized calcium?
Total calcium may be low.
What should be measured in states of hypocalcemia for accurate assessment?
Whole blood ionized calcium.
What are the criteria for hypocalcemia in newborns weighing more than 1500g?
Total calcium < 2 mmol/l,
Ionised calcium < 1.1 mmol/l.
What are the criteria for hypocalcemia in newborns weighing less than 1500g?
Total calcium < 1.75 mmol/l,
Ionised calcium < 0.9 mmol/l.
When are signs of hypocalcemia rare in newborns?
If ionized calcium > 0.8-0.9 mmol/l.
Signs of hypocalcaemia
- Jitteriness.
- Neuromuscular irritability.
- High pitched cry.
- Seizures.
- Stridor/ wheezing.
- Tetany.
- Decreased mycocardial function.
Some newborn infants may be asymptomatic.
When is hypocalcemia common in newborns?
Between 12 and 72 hours of life.
Which infants are especially prone to hypocalcemia during this time?
Preterm infants.
What may be a contributing factor to hypocalcemia during this period?
PTH immaturity.
After the initial period, what becomes the primary determinant of calcium levels?
Feeding.
When does early hypocalcemia occur?
In the first 2-3 days of life.
How is early hypocalcemia characterized in terms of normal physiological changes?
It is an exaggeration of a normal physiological drop.
Causes of early hypocalcemia
- Prematurity
* 1/3 of preterm infants have low calcium levels. - Infant of diabetic mothers (IDM)
- Perinatal hypoxia
- Di George syndrome
- Intrauterine growth restriction
- Maternal hyperparathyrodism
- Hypomagnesemia
- Hypoparathyrodism
- Maternal Vitamin D deficiency
Di George syndrome
- Hypoplastic parathyroid glands.
- 1 in 4000 newborn infants.
- 90%: deletion of 22 q.