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Severe symptomatic hyponatraemia — MCCQE Part 1 MCQ

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HardSeizuresSevere symptomatic hyponatraemiaMCCQE Part 1

A 51-year-old man with schizophrenia is found confused after drinking large volumes of water. He has a witnessed generalized tonic-clonic seizure. Sodium is 116 mmol/L, serum osmolality is low, and glucose is normal. What is the most appropriate next step in management?

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Correct answer: B — Administer hypertonic saline with close sodium monitoring

Seizure with severe hyponatraemia is a neurologic emergency requiring controlled hypertonic saline to raise sodium enough to stop cerebral oedema. Fluid restriction is too slow for symptomatic severe hyponatraemia. Oral sodium tablets are inappropriate acutely. Dextrose does not treat hypotonic hyponatraemia and may worsen free-water burden.

Reference: Canadian Society of Nephrology; hyponatraemia guidance