Hypermagnesaemia CKD Treatment — ESENeph MCQ

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ModerateElectrolyte DisordersHypermagnesaemia CKD TreatmentESENeph

A 40-year-old woman with CKD G3a develops hypermagnesaemia (Mg2+ 2.8 mmol/L) after taking large quantities of magnesium-containing antacid for dyspepsia. She has muscle weakness, hypotension, and prolonged PR interval. What is the treatment?

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Correct answer: B — Stop magnesium and give IV calcium

Hypermagnesaemia is uncommon but can be life-threatening. It occurs most commonly in CKD patients taking magnesium-containing medications (antacids, laxatives, supplements). Symptoms progress with severity: loss of deep tendon reflexes (Mg >4 mmol/L), respiratory depression, cardiac arrest (Mg >6 mmol/L). Treatment: stop all magnesium intake, IV calcium gluconate (antagonises magnesium at the neuromuscular junction), IV saline (promotes renal excretion if GFR allows), and haemodialysis for severe/refractory cases or when renal function is impaired. CKD patients should avoid magnesium-containing antacids/laxatives. The competing options do not fit the renal phenotype, temporal relationship, treatment threshold or safety constraint described. Management still requires confirmation of current medicines, renal trajectory and relevant contraindications, followed by timely biochemical and clinical reassessment. Escalate urgently if life-threatening electrolyte disturbance, respiratory compromise, shock, neurological deterioration or a dialysis indication develops.

Reference: NICE BNF – Magnesium; Kraft et al 2005 – Hypermagnesaemia Review: https://www.nice.org.uk/guidance/ng148/chapter/recommendations