Calcium - Hypocalcaemia
The classification of causes of hypocalcaemia:
hypoparathyroidism surgical (post-op) is the commonest cause, can also be auto-immune
vitamin D deficiency/resistance
renal failure, and renal losses (loopm diuretics)
drug related-cytotoxics, PPIs
metastatic disease e.g. osteoblastic secondaries (breast, prostate)
large voume blood transfusions
Symptoms and Signs
Neurological: Seizures, lethargy, paraesthesia, tetany, respiratory arrest
Cardiovascular: Heart block, heart failure, ECG prolonged QT and rarely Torsades
Dermatological: Dry skin, brittle hair
Other: Cataracts, abdominal pain, diarrhea
Chvostek and Trousseau signs (see below)
Tapping over the facial nerve anterior to the tragus causes contraction of the facial muscles
Inflation of a BP cuff causes carpopedal spasm
Mild – moderate (asymptomatic >1.9 mmol/L corrected):
Oral Calcium supplements
Find and treat the cause (in hospital setting is often post surgical)
Severe (Symptomatic or ≤ 1.9 mmol/L corrected)
10mLs 10% Calcium Gluconate in 5% Dextrose over 10mins, can be repeated.
Infusion is 100mLs of 10% calcium gluconate (ten vials) in one litre of Normal Saline or Dextrose 5% infused starting at 50-100mLs/hour, titrate to normocalcaemia.
Sampling for levels should be done at 2-6 hourly depending on degree and symptoms.
Calcium chloride can be used via a central line and will be run at reduced rates as it contains more 3 times more elemantal calcium, avoid use peripherally.
There appears to be no difference in rate of bio-availability. See ALiEM - Mythbuster Calcium Gluconate Raises Serum Calcium as Quickly as Calcium Chloride.
Find and treat the cause.