hypOcalcemia & hypOthermia

Question 1

definition of hypocalcemia

Answer 1

🔵In premature infant <1500 gm birth weight
total serum calcium is < 7 mg/dl
(ionized calcium < 4 mg/dl).

🔵In term infants or premature infants >1500 gm birth weight, total serum Ca concentration < 8 mg/dL (2 mmol/L) or an ionized fraction of < 4.4 mg/dL (1.1 mmol/L).

Question 2

Ca in plasma

Answer 2

40% protein bound
50% ionized (active)
10% non-ionized

Question 3

types of hypocalcemia

Answer 3

1- early 1st 3 days
2- late 3d - weeks

Question 4

Early neonatal hypocalcemia occur in :

Answer 4

1- LBW infants (premature and IUGR).
2- Birth asphyxia.
3- IDM.

Question 5

prevention of Early neonatal hypocalcemia

Answer 5

IV or oral Ca at a rate of 25-75 mg/kg/day

side effects : irritation & ↑ stool frequency.

Question 6

Etiology of Late neonatal hypocalcemia

Answer 6

🟢Elevated serum phosphate
🟢or low serum magnesium level.

1- Usually hypocalcemia and tetany only expressed in infants received high phosphorus containing milk.

2- Primary hypoparathyroidism (DiGeorge syndrome).

3- Maternal hyperparathyroidism.

4- Parathyroid hormone resistance.

5- Vitamin D deficiency.

6- Malabsorption, alkalosis, and transfusion with citrate- containing preservatives also has been associated with late onset neonatal hypocalcemia.

Question 7

clinical feature of late neonatal hypocalcemia

Answer 7

1- Usually the infant is well, full term, normal delivery, feed normally with normal cry before sudden onset of convulsion.

2- Fits last few seconds, generalized or focal clonic seizures can occur, between them the infant is alert, but jittery, ↑ tendon reflexes, and ↑ tone with extension.

3- Fits may continue several weeks if untreated.

4- Laryngospasm with cyanosis and apnea may occur.

5- On occasion, heart failure has been associated with hypocalcemia.
6- Chvostek sign and Trousseau sign are rare in immediate newborn period.

Question 8

dx of late neonatal hypoclacemia

Answer 8

↓ Serum Ca, ↑ phosphorus (sometime to 10-12 mg/dl) usually with associated moderate hypomagnesemia.

Question 9

Rx of late neonatal hypocalcemia

Answer 9

🟡without seizure
. prevention
@ 25 - 75 mg/kg/day of elemental calcium and evaluating serum levels every 6 to 8 hours.
@After normal calcium levels are achieved, the intravenous dose can be weaned over 2 to 3 days.

🟡 with seizure
infusion of a bolus of intravenous calcium (10% calcium gluconate, 2mL/kg) over 10 minutes

Question 10

Rx of hypomagnesemia

Answer 10

Magnesium sulfate 50%
🔹2 - 5 mg/kg of elemental magnesium
🔹or 0.1- 0.2 ml/kg given IM or by slow intravenous infusion over 20 minutes.

Question 11

definition of hypothermia

Answer 11

Normal body temperature 36.5-37.5 °C.
• At 36-36.4 °C the newborn is under cold stress.
• 32-35.9 °C is moderate hypothermia.
• Below 32 °C is severe hypothermia.

Question 12

Ways of heat loss

Answer 12

1. Evaporation: when fluid evaporates from wet skin to the air
2. Conduction: when there is direct contact to the skin with a cooler object or surface (table, weighing scale) particularly metallic surface.
3. Radiation: from infant to cooler object even when not in contact with the infant (close to cold wall, a window).
4. Convection: loss of the heat to the cooler surrounding air (naked infant exposed to a room temperature of < 25 °C).

Question 13

Why more risk in premature babies?

Answer 13

brown fat
- that is highly thermogenic
- surrounds the heart, great vessels, and
adrenals. It has a very high metabolic rate.

Question 14

Prevention of hypothermia

Answer 14

1. Drying the infant immediately after birth.
2. Direct skin to skin contact with mother & covering both with a heavy clean blanket. This will decrease heat loss, warm the baby, stimulate breast feeding & prolongs the duration of lactation.
3. Warm room ideal 25-28 °C room temperature for delivery.
4. Put the baby to the mother breast, initiate breast feeding, within a half hour of birth.
5. Warm cap on the baby’s head.

Question 15

Signs of hypothermia

Answer 15

Early clinical signs:
▪️the feet are cold to touch (before the body)
▪️weak sucking
▪️decrease activity
▪️lethargy
▪️weak cry.

Question 16

signs of cold injury

Answer 16

Lethargy with slow, shallow, irregular respiration & bradycardia
(bradycardia is a function of the degree of temperature depression), hypoglycemia, metabolic acidosis, hypokalemia & azotemia.

The face & extremities may have a bright  red  color, while the rest of the body is pale (decrease dissociation of oxyhemoglobin), and central cyanosis may be present.
 Sclerema  (a  hardening  of  the  skin)   with  reddening  &  edema  is  seen mainly on the back & the limbs, but may cover the whole body.

 Prolonged  cold  injury  lead  to   general  hemorrhage  (especially  pulmonary) and jaundice.
  Impaired  cardiac  function  &  impaired  growth  have been found in neonatal hypothermia.