• Hypocalcemia is a common metabolic problem in newborns.

• The diagnosis, cl inical manifestations, and treatment of neonatal hypocalcemia will be reviewed.

• Patient born preterm at 34 weeks• Normal spontaneous vaginal

delivery• Birth Weight: 2050 g• APGAR 8

• 28 year old G1P0• Irrelevant medical History• Denies smoking• No medication use• No HTN, no DM• Negative serologic studies

• Irritable, with weak cry• +ve hypertelorism• jaw held tightly closed• cleft palate• CV: RR, systolic murmur• Extremities: hypertonic

• CBC: WNL• CMP: WNL except Ca• Ca: 6.0 mg/dL • P: 9.2 mg/dL (4.5-9.0)• Mg: 1.5 mEq/L (1.3-2.0)• PTH: 44 pg/mL (N 40-100)

•2D Echo reveals a small VSD•Hypoplastic thymus

•Hypocalcemia•Hypoparathyroidism•VSD•Hypoplastic thymus

• Plasma calcium totals 2.4 mM (9.4 mg/dl)– Free calcium is 1.2 mM

– Albumin

– Blood pH

– Serum phosphate

– Serum magnesium

– Serum bicarbonate

Hormone Effect Bone Gut Kidney

PTH Ca Po4 Increases Osteoclasts

Indirect via Vit. D

Ca reabPo4 exr.

Vit D3 Ca Po4 No direct action

Ca Po4 absorption

No direct effect

Calcitonin Ca Po4 Inhibits Osteoclasts

No direct effect

Ca & Po4 excretion

• Ca messenger system – regulates cell function

• Activates cellular enzyme cascades

• Smooth muscle and myocardial contraction

• Nerve impulse conduction

• Secretory activity of glands

• Neuromuscular excitabil ity

• Tetany• Seizures• Stridor or cyanosis

from laryngospasm• Hypotension• Impaired cardiac

contractil ity

• May be unspecific– Asymptomatic– Lethargy– Poor feeding– Vomiting– Abdominal distention

• Fetus: Ca and P concentration higher than mother plasma, s Ca falls at 24 hrs.

• Neonates: Ca lower than children at 2 n d and 3th day

• Return to normal by 5-10 days

•Total serum Ca less than:– 7.0 mg/dL in Preterm infants– 8.0 mg/dL in Term newborns– 8.8 mg/dL in children

Early neonatal hypocalcemia (48-72 hours)Prematurity

Poor intake, hypoalbuminemia, ↓ responsiveness to vit D

Birth asphyxiaDelayed feeding, ↑ calcitonin, endogenous

phosphate load , alkali therapy

Infant of diabetic motherMg depletion functional hypoparathyroidism → →

↓ CaIUGR

Late neonatal hypocalcemia (Full term)

•Exogenous phosphate load•Mg deficiency

•Transient hypoparathyroidism of newborn

•Congenital Hypoparathyroidism

•Maternal Vit D deficiency•Maternal Hyperparathyroidism•Gentamycin

Bicarbonate infusion → metabolic alkalosis

Transfusion with citrated blood→ formation of Ca complexes, ↓ Ca++

Lipid infusions → Ca complexes with FFAs → ↓ Ca++

Phototherapy for hyperbil irubinemia Acute renal failure →

hyperphosphatemiaRotavirus infection

•  ↓ Mg → impaired PTH secretion & resistance to PTH → hypocalcemia

• Usually idiopathic & transient

• May be secodary to disorders of intestinal and/or renal tubular Mg transport

• Antagonizes PTH secretion or actions → ↑ Ca & P deposition in bones → hypocalcemia.

 

Cardiac defects, Abnormal facies, Thymic hypoplasia, Cleft palate, and Hypocalcemia caused by Chromosome 22 deletion

DiGeorge Syndrome is a severe phenotype of this group of related disorders.

FISH establishes the diagnosis.

• What is the diagnosis?

• How could we confirm the diagnosis?

• Total Ca• Ionized Ca• Phosphorus• Magnesium

• PTH • Vitamin D • Liver function• Renal function

Only in infants with risk factors

Measure Ca at 24, and 48 hrs of age.

Measure Ca in infants with congenital heart ds.

Ionized Ca should be the primary measurement.

1. Depends on underlying cause & severity

2. Mild asymptomatic : ↑ dietary Ca by initiating early feeding

3. For infants who require parenteral nutrit ion, Ca is added to the solution .

4. If symptomatic: treat immediately

– Ca gluconate:10 mg/kg (1 ml/kg of 10% solution) Slowly IV

– Start oral Calcium as soon as possible

– Early neonatal hypocalcaemia normalizes in 2-3 d

Late neonatal hypocalcemia– Associated with ↑ S-phosphate

–Decrease phosphate intake– Give calcium containing phosphate

binder – Oral calcium gluconate 100

mg/kg/dose 4 hourly

– Tissue necrosis/calcif ication if extravasates

– Calcium can inhibit sinus node → bradycardia + arrest

– Avoid complete correction of hypocalcemia

– Give Ca before correcting acidosis

– If ↓ Mg – f irst treat & correct hypomagnesemia