Classification of Plasma Magnesium Concentration
| Plasma magnesium concentration (mmol/L) | Classification | Clinical and ECG features |
|---|---|---|
| >2.50 | Severe hypermagnesaemia | Seizures, respiratory depression, hypotension Atrioventricular block, cardiac arrest |
| 1.50–2.50 | Moderate hypermagnesaemia | Nausea, hyporeflexia |
| 1.20–1.50 | Mild hypermagnesaemia | Usually asymptomatic |
| 0.70–1.20 | Normal range | |
| 0.60–0.70 | Mild hypomagnesaemia | Usually asymptomatic |
| 0.50–0.60 | Moderate hypomagnesaemia | Nausea, abdominal pain Paraesthesiae, muscle cramps |
| <0.50 | Severe hypomagnesaemia | Tetany, seizures, muscle weakness, ataxia ECG: PR prolongation, widened QRS, ST depression, torsade de pointes |