Abnormalities of Serum Calcium and Magnesium

Question 1

Definition of hypocalcemia in newborn ……?

Answer 1

total serum calcium concentration of <7 mg/dL or

an ionized calcium concentration of <4 mg/dL (1 mmol/L)

Question 2

Function of calcium in body …?

Answer 2

blood coagulation,

neuromuscular excitability,

cell membrane function, and

cellular enzymatic and

secretory activity.

Question 3

Hypocalcemia in preterm why ..?

Answer 3

Preterm infants are capable of mounting a PTH response to hypocalcemia, but target organ responsiveness to PTH may be diminished

Question 4

Why hypocalcemia in Infants of diabetic mothers (IDMs) …?

Answer 4

Hypercalcitoninemia, hypoparathyroidism, abnormal vitamin D metabolism, and hyperphosphatemia have all been implicated, but the etiology remains uncertain.

Question 5

Perinatal asphyxia and hypocalcemia…?

Answer 5

Decreased calcium intake and increased endogenous phosphate load are the likely causes

Question 6

Congenital cause of hypocalcemia

Answer 6

Parathyroid glands may be absent in DiGeorge sequence (hypoplasia or absence of the third and fourth branchial pouch structures

Question 7

CATCH-22 syndrome…?

Answer 7

CATCH-22 syndrome, an acronym for cardiac defects, abnormal facies, thymic hypoplasia, cleft palate, and hypocalcemia caused by chromosome 22q11 deletion.

Question 8

Pathophysiology of Pseudohypoparathyroidism ..?

Answer 8

Pseudohypoparathyroidism is associated with resistance to the PTH hormone.

It can be caused by GANS1 mutation.

Serum calcium levels are low, phosphate levels are high, despite high PTH levels.

This is due to resistance of end organs to PTH.

Question 9

How Maternal hyperparathyroidism is implicated in neonatal hypocalcemia…?

Answer 9

Unrecognized maternal hyperparthyroidism causes maternal hypercalcemia, this results in fetal hypercalcemia, which in turn suppresses parathyroid activity in the fetus and later impaired parathyroid responsiveness to hypocalcemia after birth

Question 10

How magnesium deficiency causes the hypocalcemia …?

Answer 10

Magnesium is required for release of parathyroid hormone so deficiency will results in no release of PTH so hypocalcemia

Question 11

Normal levels of magnesium

Answer 11

Normal serum levels of magnesium (Mg) are 1.6 to 2.8 mg/dL

Question 12

How Massive transfusion leads to hypocalcemia..?

Answer 12

Rapid infusion of citrate-buffered blood (exchange transfusion) chelates ionized calcium and causes hypocalcemia.

Question 13

How Phototherapy causes the neonatal hypocalcemia…?

Answer 13

Phototherapy may be associated with hypocalcemia by decreasing melatonin secretion and increasing uptake of calcium into the bone.

Question 14

Late-onset hypocalcemia. …?

Answer 14

High phosphate intakes (high phosphate–containing formula milk) lead to excess phosphorus and decreased serum calcium.

Question 15

Signs of hypocalcemia ,…?

Answer 15

The signs are usually nonspecific: apnea, seizures, jitteriness, increased extensor tone, clonus, hyperreflexia, and stridor (laryngospasm)

Question 16

Calcium concentration may be reported as milligrams per deciliter or as molar units ….?

Answer 16

10 mg/dL converts to 2.5 mmol/L

Question 17

Hypocalcemia in metabolic bone disease …?

Answer 17

metabolic bone disease (usually 4 weeks and beyond) in extreme preterm babies, the serum calcium and phosphorus levels are both decreased.

This hypocalcemia is primarily due to renal tubular losses of phosphorus (due to immaturity) with added nutritional component. Urinary phosphorus is high

Question 18

In most cases of early hypocalcemia, ionized calcium levels will be low and phosphorus levels moderate to severely elevated. This hypocalcemia is a result of…?

Answer 18

poor PTH activity.

Question 19

Dose of IV calcium …?

Answer 19

parenteral nutrition (PN)- A dose of 40 to 50 mg/kg/day of elemental calcium

Emergency calcium therapy-100 to 200 mg/kg of 10% calcium gluconate (9 to 18 mg of elemental calcium per kilogram) by intravenous infusion over 10 to 15 minutes

Question 20

How to Correction of associated hypomagnesemia..?

Answer 20

Give 50% magnesium sulfate solution (500 mg or 4 mEq/mL)—25 to 50 mg/kg or 0.2 to 0.4 mEq/kg per dose—every 12 hours, IV over at least 2 hours or intramuscular (IM)

Question 21

Definition of Neonatal hypercalcemia..?

Answer 21

serum total calcium level >11 mg/dL,

serum ionized calcium level >1.45 mmol/L

Question 22

Neonatal severe primary hyperparathyroidism (NSPHP)

Answer 22

The parathyroid glands are refractory to regulation by calcium, producing marked hypercalcemia (frequently 15 to 30 mg/dL).

Question 23

How Hyperthyroidism leads Hypercalcemia ……?

Answer 23

Thyroid hormone stimulates bone resorption and bone turnover.

Question 24

Reason for developing hypercalcemia in Subcutaneous fat necrosis is a sequela of trauma or asphyxia..?(NEET 2022)

Answer 24

Granulomatous (macrophage) inflammation of the necrotic lesions may be a source of unregulated 1,25(OH)2D3 synthes

Question 25

Idiopathic neonatal/infantile hypercalcemia occurs in the constellation of which ’ syndrome…?

Answer 25

hypercalcemia, supravalvular aortic stenosis or other cardiac anomalies, “elfin” facies, psychomotor retardation

Question 26

Definition for hypomagnesemia …?

Answer 26

Low serum magnesium level of <1.6 mg/dL suggests hypomagnesemia.

Question 27

Treatment for hypomagnesemia ..?

Answer 27

Correct severe hypomagnesemia (<1.6 mg/dL) with 50 mg/kg of magnesium sulfate intravenously or intramuscularly given over 1 to 2 hours.