Care of Children With a Hypocalcemic Crisis
The following guidelines are generally applicable. Individual situations
may require deviation from these guidelines.
ACUTE PRESENTATION
- Tetany
- Seizure
- Laryngospasm/stridor
- Arrhythmias (Prolonged Q-T interval, conduction abnormalities with
bradycardia)
- Circumoral numbness
- Extremity parasthesiae
- Trousseau’s sign (carpal spasm by 3 minutes after interrupted vascular
flow to arm)
- Chvostek’s sign (facial twitch caused by tapping below zygoma)
- Infants may show lethargy, vomiting, poor feeding
DIFFERENTIAL DIAGNOSIS
Early Neonatal (within first 3 days)
- Prematurity
- Hypoxic encephalopathy
- Infant of Diabetic Mother
- Magnesium deficiency
- Exchange transfusion (citrate)
Late Neonatal
- Idiopathic hypoparathyroidism
- Maternal hypercalcemia
- Congenital Aplasia (DiGeorge Syndrome, Velo-cardio-facial Syndrome)
- Cow’s milk tetany (high phosphate cow’s milk)
- Hypomagnesemia (Mg malabsorption, renal loss)
- Chronic diarrhea (calcium malabsorption, alkaline treatment for
acidosis)
- Severe Infantile Osteopetrosis
Childhood
- Hypoparathyroidism
- Autoimmune (isolated, type 1 polyglandular syndrome)
- Post-surgical, post-irradiation
- Hypomagnesemia
- Pseudohypoparathyroidism
- Infiltration (iron overload, Wilson’s disease)
- Hyperphosphatemia
- Chelation (e.g. Citrate)
- Acute severe illness (e.g. sepsis, toxic shock syndrome)
- Pancreatitis
- Respiratory alkalosis
- Rickets (rare)
- “Hungry bone” syndrome (e.g. after treating Vit D deficiency)
- Tumor mets
DIAGNOSIS
Order STAT calcium, phosphorus, magnesium, albumin, ionized Calcium (if
possible)
Note: In chronic illness, total calcium is decreased 0.8
mg/dL for every 1g/dL decline in albumin (but equation accuracy not
confirmed in acutely ill patients)
If patient is symptomatic, worry about primary cause later
TREATMENT
1) Acute correction of hypoalcemia is indicated if patient is
symptomatic
20 mg/kg elemental calcium IV over 10-20 minutes
Equal to:
2 mL/kg 10% calcium gluconate
0.7 mL/kg 10% calcium chloride
Ensure IV is running well to avoid subcutaneous tissue burn
Can repeat every 6-8 hours
OR
Follow with infusion:
<2 years old - 8 mL/kg/day 10% calcium gluconate OR 3 mL/kg/day 10% Ca
chloride
>2 years old – 5 mL/kg/day 10% calcium gluconate OR 2 mL/kg/day 10% Ca
chloride
MONITOR SERUM Ca++ frequently while on infusion
Ensure solution is dilute to minimize risk of burn
Never mix calcium with fluids containing phosphate or bicarbonate
2) Acute correction of Hypomagnesemia for Mg< 1.5 mg/dL
7-15 mg/kg of elemental Mg IV in 24 hour infusion
Equal to:
0.15-0.3 mL/kg/day of 50% Mg sulfate (compatible with dextrose and saline)
0.3-0.6 mL/kg/day of 20% Mg chloride
OR 0.2 mL/kg IM q8-12h of 50% Mg sulfate
IV Mg is excreted rapidly
Therefore, start Mg oxide 250-500 mg po QID as soon as possible
3) Diagnose and treat primary cause of hypocalcemia |