Adult with low calcium
Low albumin-adjusted or ionised calcium. Adults only: neonates and children need a weight-based paediatric protocol.
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EndocrinologyEmergency
Severe Hypocalcemia Management
Severe Hypocalcemia Management: Adult with low calcium → Look for symptoms and ECG changes; send bloods → Symptoms, ECG changes, or adjusted calcium bel...
Pathway Overview
14 steps
Algorithm Steps
14 total
01Start 02Action Look for symptoms and ECG changes; send bloods
Neuromuscular irritability is the main sign. Symptoms usually start below adjusted calcium 1.9 mmol/L, but this depends on how fast it falls.
- Perioral and finger paraesthesiae
- Chvostek and Trousseau signs
- Tetany, carpopedal spasm, laryngospasm
- Seizures
- 12-lead ECG: prolonged QT, arrhythmia
- Send: adjusted calcium, phosphate, magnesium, PTH, urea, creatinine and electrolytes, 25-OH vitamin D
03Decision Symptoms, ECG changes, or adjusted calcium below 1.9 mmol/L?
Yes = severe hypocalcaemia, a medical emergency. No = mild (no symptoms and adjusted calcium 1.9 mmol/L or more). The 1.9 mmol/L cut-off is adjusted total calcium, not ionised calcium: with only an ionised result, decide by symptoms and ECG and check adjusted calcium.
- If Yes
- Yes: severe
04Warning Before IV calcium: digoxin, high phosphate, dialysis
Do not delay IV calcium for seizures, laryngospasm or arrhythmia.
- Digoxin: arrhythmia risk. If IV calcium is needed, give it slowly in small amounts with continuous ECG monitoring; get senior advice.
- High phosphate (tumour lysis, rhabdomyolysis, kidney failure): give IV calcium only for symptoms, at the lowest dose that relieves them.
- Dialysis or end-stage kidney failure: no large-volume calcium infusion; get renal advice.
05Action Severe: IV calcium gluconate bolus now
Adults only (children: paediatric protocol). Symptomatic, ECG changes, or adjusted calcium below 1.9 mmol/L.
- Calcium gluconate 10% 10-20 mL (2.2-4.4 mmol calcium) in 50-100 mL glucose 5% IV over 10 min
- Continuous ECG monitoring. Repeat the bolus until symptoms stop.
- Separate line: do not mix with bicarbonate or phosphate
- Calcium chloride only via a central line. AU calcium chloride 10% 10 mL = 6.8 mmol (3 times gluconate): calculate the volume.
- Then start a calcium gluconate infusion (next step)
06Action Severe: continuous calcium gluconate infusion
After the bolus. Continue until treatment of the cause takes effect.
- Calcium gluconate 10% 100 mL (10 × 10 mL vials) in 1 L sodium chloride 0.9% or glucose 5%
- Start at 50-100 mL/h (about 1-2 mmol calcium/h)
- Titrate to normal calcium; check adjusted or ionised calcium every 4-6 h
- Watch the IV site: extravasation causes tissue injury
07Action Check magnesium; correct if low
Calcium will not correct while magnesium is low. Do this for every patient, mild or severe.
- Low magnesium: magnesium 24 mmol IV over 24 h (6 g magnesium sulfate) in 500 mL sodium chloride 0.9% or glucose 5%
- Seizures or arrhythmia with low magnesium: get senior advice now on a faster IV loading dose
- Kidney impairment: use a lower dose and check magnesium often (risk of toxicity)
- Stop drugs that cause it (for example PPIs, diuretics)
- Aim for normal serum magnesium
08Action Find and treat the cause
Start specific treatment of the cause early.
- After total thyroidectomy (most common): hypoparathyroidism, transient or permanent
- After parathyroidectomy: usually transient; hungry bone can cause severe, prolonged low calcium
- Vitamin D deficiency; low magnesium
- Pancreatitis, rhabdomyolysis, large-volume blood transfusion
- Kidney failure: check phosphate and PTH
- Drugs: denosumab, bisphosphonates, cinacalcet, cytotoxics
09Action Monitor during treatment
While calcium is being replaced. The IV items apply to the severe branch.
- ECG monitoring during IV calcium
- Adjusted or ionised calcium every 4-6 h while on IV calcium
- Magnesium, phosphate, creatinine and potassium daily
- Calcitriol can cause hypercalcaemia: check calcium often while doses are set
10Action When stable: oral calcium and active vitamin D
Severe branch: when symptoms are gone and calcium is stable, overlap oral therapy before the IV infusion stops. Mild branch: continue the mild oral plan.
- Oral calcium: 2-3 g elemental calcium twice daily (SfE); adjust to calcium results
- Hypoparathyroidism after IV treatment, or post-surgery calcium still low beyond 72 h: calcitriol 0.25-0.5 microgram daily to start; titrate
- Take levothyroxine at least 4 h apart from calcium
- On calcitriol: adjusted calcium 1 week after discharge, then at 1, 3 and 6 months; calcium specialist follow-up
11Decision Permanent cause, such as hypoparathyroidism over 12 months after surgery?
Postsurgical hypoparathyroidism is chronic when it lasts more than 12 months; recovery can still occur later.
- If Yes
- Yes: permanent
12Outcome Permanent: chronic hypoparathyroidism, specialist care
Calcium and calcitriol. Target adjusted calcium in the lower half of normal (or just below) without symptoms, and avoid high urine calcium. Pregnancy: specialist care; targets and doses change.
- Avoid hypercalciuria: 24-h urine calcium below 6.25 mmol (women) or 7.5 mmol (men)
- Keep magnesium, phosphate and 25-OH vitamin D normal
- Check calcium, phosphate, magnesium and creatinine every 3-12 months when stable
- Poor control on standard therapy: specialist may use PTH replacement (palopegteriparatide, TGA-registered 2025)
- Pregnancy: specialist care; calcium needs change
If No- No: transient
13Outcome Transient: calcium normal, supplements weaned
Wean calcium and calcitriol as the cause resolves. Follow up as the cause needs.
If No- No: mild
14Action Mild: oral calcium (no symptoms, adjusted calcium 1.9 mmol/L or more)
Adults only. Check magnesium (next step) and treat the cause.
- Oral calcium: SfE dose is 2 g elemental calcium twice daily (calcium carbonate 1.5 g tablet = 600 mg calcium)
- CKD stage 4-5 or dialysis: get renal advice before high-dose oral calcium. Mild low calcium without symptoms can be tolerated to avoid calcium load.
- After thyroidectomy: repeat calcium in 24 h. Above 2.1 mmol/L: may go home; recheck within 1 week.
- Still 1.9-2.1 mmol/L: increase to 3 g elemental calcium twice daily. Beyond 72 h: add calcitriol 0.25 microgram daily.
- Vitamin D deficiency: cholecalciferol about 300,000 units in total over 6-10 weeks
- Path rejoins step 07Shared downstream outcome
Guideline Source
Society for Endocrinology Endocrine Emergency Guidance: Emergency management of acute hypocalcaemia in adult patients (Turner et al., Endocr Connect 2016; addendum 2019)
Clinical Safety Information
Clinical Decision Support — Not a Substitute for Clinical Judgment
Individual patient factors may require deviation from these recommendations.
Known Limitations
- Adults only. Neonates and children need a weight-based paediatric protocol.
- Dialysis, end-stage kidney failure or high phosphate: get renal advice before large IV calcium doses.
- Calcium will not correct until low magnesium is corrected.
- Pregnancy with hypoparathyroidism needs specialist care (targets and doses change).
Contraindicated Populations
neonateschildren (use a weight-based paediatric protocol)
Applicable Regions
AUUSEUUK
AU: Calcium gluconate 10% 10 mL = 2.2 mmol calcium; calcium chloride 10% 10 mL = 6.8 mmol (AU PI). Labs report calcium and magnesium in mmol/L. Palopegteriparatide (Yorvipath) TGA-registered Feb 2025 for chronic hypoparathyroidism in adults.
UK: Society for Endocrinology emergency guidance 2016 and 2019 addendum. UK calcium chloride strengths differ (7.35% and 14.7%).
US: Calcium is often reported in mg/dL: 1.9 mmol/L = 7.6 mg/dL; 2.1 mmol/L = 8.4 mg/dL.
Version 2Next review: 2027-09-30
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Related Resources
Frequently Asked Questions
What is the Severe Hypocalcemia Management?
The Severe Hypocalcemia Management is a emergency clinical algorithm for Endocrinology. It provides a structured decision tree to guide clinical decision-making, based on Society for Endocrinology Endocrine Emergency Guidance: Emergency management of acute hypocalcaemia in adult patients (Turner et al., Endocr Connect 2016; addendum 2019).
What guideline is the Severe Hypocalcemia Management based on?
This algorithm is based on Society for Endocrinology Endocrine Emergency Guidance: Emergency management of acute hypocalcaemia in adult patients (Turner et al., Endocr Connect 2016; addendum 2019) (DOI: 10.1530/EC-16-0056).
What are the limitations of the Severe Hypocalcemia Management?
Known limitations include: Adults only. Neonates and children need a weight-based paediatric protocol.; Dialysis, end-stage kidney failure or high phosphate: get renal advice before large IV calcium doses.; Calcium will not correct until low magnesium is corrected.; Pregnancy with hypoparathyroidism needs specialist care (targets and doses change).. Individual patient factors may require deviation from these recommendations.
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