Magnesium - Hypomagnesaemia

Causes

The most common causes for patients seen in the ED are malnutrition, malabsorption and alcoholism, alone or in combination. Pancreatitis and insulin administration along with renal failure, (acute tubular necrosis) and renal active drugs (diuretics, aminoglycosides) make up the rest.

Signs and Symptoms

CVS:

• tachydysrhythmias (VT, torsades de pointes)

• prolonged QT

Metabolic:

• hypocalcaemia

• hypokalaemia

Neurological:

• tetany

• seizures     

Management

Mild to moderate <0.7mg/dL and asymptomatic:

• Oral magnesium supplements

• Find and treat cause

• Seek and treat other electrolytes disturbances

Severe <0.7mg/dL:

• IV Mg 2.5g (10mmol) over 20-30 mins

• Find and treat cause