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Severe symptomatic hyponatraemia — MRCEM SBA MCQ

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HardResuscitation and critical illnessSevere symptomatic hyponatraemiaMRCEM SBA

A 62-year-old woman taking indapamide has had worsening confusion and poor oral intake for four days. In the emergency department she has a generalised seizure that stops after 80 seconds. Fifteen minutes later she remains disorientated, with a Glasgow Coma Scale score of 12, but is breathing adequately and maintaining her airway. Laboratory sodium is 111 mmol/L, confirmed on a venous blood gas; glucose is 5.4 mmol/L. She is haemodynamically stable, without pulmonary oedema. A free-flowing large-bore peripheral cannula and 2.7% sodium chloride are available. Critical care has been contacted, but no central venous line is in place. Which is the most appropriate immediate treatment plan?

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Correct answer: E — Give 150 mL of 2.7% sodium chloride over 20 minutes through peripheral access; arrange monitored critical care.

The seizure, persistent impaired consciousness and confirmed sodium of 111 mmol/L indicate severe symptomatic hyponatraemia. Poor intake raises concern about overly rapid correction, but does not justify postponing treatment of the immediate neurological emergency. Adult UK guidance recommends 150 mL of 2.7% sodium chloride over 20 minutes. The available free-flowing, large-bore peripheral cannula permits prompt administration while critical care is arranged; inspect the site for extravasation. Recheck sodium after the bolus and determine further treatment from the neurological and biochemical response. The aim is initial symptom relief, not rapid normalisation of sodium; subsequent correction must be limited and monitored. ([apps.worcsacute.nhs.uk](https://apps.worcsacute.nhs.uk/KeyDocumentPortal/Home/DownloadFile/4442)) A is an isotonic fluid bolus, not the indicated initial treatment for these severe neurological symptoms. B offers the appropriate hypertonic bolus but delays it unnecessarily for central access. C uses the appropriate preparation but delivers the initial dose too slowly. D uses a lower-concentration preparation at the same volume, delivering less sodium; an alternative 1.8% regimen requires an appropriately adjusted volume under local guidance. E provides the indicated bolus promptly without delaying monitored care. ([apps.worcsacute.nhs.uk](https://apps.worcsacute.nhs.uk/KeyDocumentPortal/Home/DownloadFile/4442))

Reference: Management of Hyponatraemia in Adult Inpatients (Approved 10 January 2025) — https://apps.worcsacute.nhs.uk/KeyDocumentPortal/Home/DownloadFile/4442 Hyponatraemia Guidelines (2024) — https://www.gloshospitals.nhs.uk/media/documents/Hyponatraemia_guidelines_2024_update.pdf