Hypermagnesaemia

Question 1

Define hypermagnesaemia

Answer 1

High serum magnesium (> 1.1mmol/L)

Very uncommon

Question 2

What are the common clinical features of hypermagnesaemia

Answer 2

Majority are asymptomatic unless serum concentration is > 2 mmol/L

• Nausea
• Absent reflexes
• Hypotension
• Bradycardia

Question 3

What are the two most common causes of hypermagnesaemia

Answer 3

Renal impairment

Excess administration of magnesium

Question 4

How is hypermagnesaemia diagnosed

Answer 4

Blood test – typically incidental finding as the majority as asymptomatic

Question 5

Hypermagnesaemia management is centre on prevention.

What two ways can we prevent hypermagnesaemia

Answer 5

Avoiding magnesium-containing medications e.g. laxatives in patients with CKD

Monitoring patients receiving magnesium replacement

Question 6

What 3 interventions can be used in the management in hypermagnesaemia

Answer 6

Consider IV fluids

Consider loop diuretic (increases renal excretion of magnesium)

Dialysis often required

Question 7

Why are loop diuretic considered a part of the management of hypermagnesaemia

Answer 7

Increases renal excretion of magnesium