skip to main content

Thyrotoxic periodic paralysis — SCE Acute Medicine MCQ

Instant feedback + full explanation. One question, done properly.

HardAcute Renal and Metabolic EmergenciesThyrotoxic periodic paralysisSCE Acute Medicine

A 63-year-old man presents with vomiting, weakness, confusion or collapse. Relevant history includes diabetes, kidney disease, endocrine disease or a treatment trigger. On assessment, volume status and bedside physiology are abnormal. Investigations show episodic weakness, potassium 2.1 and suppressed TSH after carbohydrate load. What is the most likely underlying cause/mechanism?

Educational content. Not a substitute for clinical judgement or local policy.

Reveal the answer and explanation

Correct answer: A — Thyrotoxic periodic paralysis

The key discriminator is that episodic weakness, potassium 2.1 and suppressed TSH after carbohydrate load, which makes Thyrotoxic periodic paralysis the single best answer. Sodium-channel blockade is less appropriate because it does not address the dominant acute risk in the vignette; Portal hypertensive bleeding would fit a different presentation or later stage of care. Immune-mediated small-vessel vasculitis and Tissue hypoperfusion causing lactic acidosis are suboptimal because they would either delay time-critical treatment or follow the wrong acute pathway. Teaching point: SCE-style acute medicine questions usually test prioritisation using physiology, timing and a guideline-defined threshold, rather than isolated factual recall.

Reference: https://bnf.nice.org.uk/#acute-medicine-order-30-1