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Periodic paralysis hypokalaemic — SCE Neurology MCQ

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HardNeuromuscularPeriodic paralysis hypokalaemicSCE Neurology

An 18-year-old with genetically confirmed hypokalaemic periodic paralysis develops marked quadriparesis after a carbohydrate-rich meal. ECG shows prominent U waves and serum potassium is 2.2 mmol/L; respiration is currently stable. What is the safest acute treatment?

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

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Correct answer: A — Give cautious potassium replacement with continuous cardiac monitoring

A severe hypokalaemic attack with ECG change needs careful potassium replacement and cardiac monitoring because total-body potassium is not depleted and rebound hyperkalaemia can occur. Glucose can drive potassium intracellularly and worsen weakness; calcium treats membrane instability in hyperkalaemia, bicarbonate also lowers extracellular potassium, and acetazolamide is preventive rather than a substitute for acute correction.

Reference: Review of diagnosis and treatment of periodic paralysis (Published March 2018): https://pmc.ncbi.nlm.nih.gov/articles/PMC5867231/