Disorders of Plasma Calcium Concentration
| Plasma total calcium concentration (mmol/L) | Classification | Clinical and ECG features |
|---|---|---|
| >3.5 | Severe hypercalcaemia | Delirium and coma ECG: QT interval shortening |
| 3.0–3.5 | Moderate hypercalcaemia | Polyuria (from hypercalciuria-induced nephrogenic diabetes insipidus), vomiting, constipation, abdominal pain, renal calculi, joint pain |
| 2.6–3.0 | Mild hypercalcaemia | Usually asymptomatic |
| 2.2–2.6 | Normal range | |
| 1.9–2.2 | Mild hypocalcaemia | Usually asymptomatic |
| 1.5–1.9 | Moderate hypocalcaemia | Paraesthesiae, muscle cramps, positive Chvostek and Trousseau signs |
| <1.5 | Severe hypocalcaemia | Tetany, carpopedal spasm, seizures, laryngospasm ECG: QT prolongation which may progress to ventricular fibrillation or heart block |