Hypocalcaemia
Hypocalcaemia is a serum calcium of<2.0 mmol/L with an ionised fraction<0.8 mmol/L.
Symptoms and Signs
Circumoral paraesthesia, peripheral tingling and paraesthesia, cramp, tetany (carpo-pedal spasm), hypotension, hyperactive tendon reflexes, Chvostek’s sign (tapping over the facial nerve causes facial spasm), Trousseau’s sign (inflating blood pressure cuff to above systolic pressure causes carpal spasm), laryngospasm (life-threatening), cardiac arrhythmias and rarely dystonia and psychosis.
Investigations
■ Serum calcium and phosphate
Ca ↓ PO4 may be low, normal or high.
■ U&Es
↑ creatinine ↑ urea. Renal failure.
■ ABGs
pH ↑ (hypocalcaemia associated with respiratory alkalosis).
■ Serum amylase
Ca ↓ associated with acute pancreatitis.
■ Serum magnesium
↓ Mg – magnesium deficiency may lead to hypocalcaemia.
■ PTH levels
Hypoparathyroidism.
