See also

Electrolyte abnormalities 
Basic paediatric ECG interpretation

Key points

1. Severe hypocalcaemia can cause life-threatening arrhythmia or seizures
2. Commence cardiac monitoring in cases of severe and/or symptomatic hypocalcaemia or if changes on ECG
3. The oral/enteral route is preferred for replacement of calcium, unless severe hypocalcaemia
4. Seek specialist advice in children with symptomatic hypocalcaemia

Background

• This guideline does not cover hypocalcaemia in neonates <1 month of age
• Hypocalcaemia is defined as a total calcium <2.2 mmol/L or an ionised calcium <1 mmol/L. The onset of symptoms in hypocalcaemia typically occurs with a total calcium <1.8 mmol/L
• Less than 1% of the body’s total calcium is in the extracellular fluid. Half of the extracellular calcium is bound to albumin, and the other half is in its ionised active form
• The most common causes of hypocalcaemia are vitamin D deficiency and parathyroid hormone (PTH) deficiency

Common causes of hypocalcaemia

Assessment

History

• Hypocalcaemia can be chronic and/or asymptomatic, or it can present with acute/severe symptoms and signs
  • Paraesthesia, peri-oral tingling or tingling of hands and feet
  • Muscles aches or cramps
  • Irritability, mood changes, poor concentration
  • Abdominal pain, diarrhoea
  • Stridor, apnoea
  • Palpitations, arrhythmia, syncope
  • Confusion, agitation, delirium, seizures
• Assess for possible causes (see table above)

Examination

• Tachycardia, bradycardia, arrhythmia
• Spasm/tetany
• Hyperreflexia
• Positive Trousseau sign (see additional notes)
• Craniofacial features and midline defects including cleft

Assessment of severity

• Severity is determined by total calcium level and symptoms
• If any severe features present, treat as severe despite the calcium level

Investigations

If possible, collect all prior to calcium replacement

First line investigations

• Corrected calcium (also order albumin if required by local laboratory)
• Ionised calcium (venous or capillary blood gas)
• Magnesium, phosphate
• PTH
• 25 hydroxy vitamin D
• UEC
• ECG to identify conduction abnormalities (see Basic paediatric ECG interpretation). Look for QTc prolongation, arrhythmia, atrial fibrillation, torsades de pointes

Second line investigations

• ALP
• Albumin
• 1,25 vitamin D
• Urinary calcium:creatinine ratio

Other investigations will depend on suspected causes

Treatment

Goals are to

• prevent life threatening complications
• replace calcium deficit. Enteral replacement is preferred unless severe hypocalcaemia
• identify and treat reversible causes

Children with moderate to severe hypocalcaemia require ECG monitoring and IV access

Calcium should be replaced if

• corrected calcium <2.0 mmol/L or ionised calcium <1.0 mmol/L
• signs and symptoms of hypocalcaemia and/or ECG changes

Address any abnormalities of magnesium and potassium. Untreated hypomagnesaemia can make hypocalcaemia resistant to treatment. See Hypomagnesaemia

Route of administration

Oral/enteral route

• This is the preferred route of calcium replacement
• Should be given with food

IV calcium should be considered if

• Severe acute hypocalcaemia
• Presence of ECG changes

Oral/enteral dosing

* Note: Calcitriol is the most active form of vitamin D and increases absorption of calcium in 1-2 days

Oral medication forms

See below for examples of oral tablet preparations of calcium carbonate

• Other products containing different amounts of calcium (and/or cholecalciferol) may be available. Check ingredients and strengths carefully
• Some hospitals may have access to calcium carbonate oral liquid or calcium carbonate effervescent
• Calcitriol is available as a 0.25 microgram capsule

IV replacement

Should be considered in severe acute hypocalcaemia

• Requires monitoring with frequent calcium levels, ECG and observations including heart rate
• Switch from IV to oral route as soon as child is stable
• Risk of necrosis if extravasation occurs. Both calcium chloride and calcium gluconate are vesicants. Calcium gluconate is less irritating to veins and preferred if central venous access is unavailable
• Rapid administration may cause vasodilation, hypotension, bradycardia, arrhythmias and cardiac arrest
• Aim to increase and stabilise calcium levels to a safe range: corrected calcium >1.8 or ionised calcium >1.0

Severe hypocalcaemia

*Calcium level to be checked prior to each infusion

Medication forms

*Solutions compatible for dilution with calcium gluconate include 5% glucose, 0.9% sodium chloride, or glucose and saline solutions

^# Solutions compatible for dilution with calcium chloride include 5% glucose and 0.9% sodium chloride

Consider consultation with local paediatric team when

• The child is symptomatic or there is moderate to severe hypocalcaemia
• The child is <1 month of age

Consider consultation with endocrinology team when

• Child is <1 month of age
• Severe or symptomatic hypocalcaemia
• If a cause other than vitamin D deficiency is suspected

Consider transfer when

• Ionised calcium <1.0 or corrected calcium <1.8
• Symptomatic hypocalcaemia
• Significant ECG changes including prolonged QT or arrhythmia
• Risk of arrhythmia
• Neonates
• Child with complex medical condition
• Child requiring care beyond the comfort level of the hospital

For emergency advice and paediatric or neonatal ICU transfers, see Retrieval Services

Consider discharge when

• Asymptomatic and stable corrected calcium >1.8 mmol/L
• Plan for ongoing monitoring and follow-up of investigations for underlying cause

Parent information

Vitamin D

Additional notes

Positive Trousseau sign

Figure 1: Positive Trousseau sign is associated with hypocalcaemia. Trousseau sign is characterised by occurrence of carpopedal spasms (wrist flexion, metacarpophalangeal flexion, and finger adduction) on inflation of blood pressure cuff to 20 mmHg above child’s baseline systolic blood pressure for 2 to 3 minutes

Last updated July 2026