Myotonic Dystrophy Anaesthesia — FRCA Final MCQ

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HardGeneral AnaesthesiaMyotonic Dystrophy AnaesthesiaFRCA Final

A 35-year-old woman with myotonic dystrophy type 1 requires a cholecystectomy. Which anaesthetic consideration is MOST critical?

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Correct answer: D — Sevoflurane specifically worsens myotonia

In myotonic dystrophy, suxamethonium is ABSOLUTELY contraindicated because it causes severe, sustained myotonic contraction of skeletal muscles (including the jaw and chest wall) that does not respond to non-depolarising agents or dantrolene. This can make ventilation and intubation impossible. Non-depolarising agents can be used but may have unpredictable duration. Additionally, these patients have: cardiac conduction abnormalities (require pre-op ECG, may need pacing), respiratory weakness, increased sensitivity to sedatives and opioids, and impaired gastric motility. Avoid hypothermia (worsens myotonia). Regional anaesthesia is NOT contraindicated and may be advantageous.

Reference: RCOA – 2023 – Neuromuscular disease and anaesthesia; Veyckemans F – 2013 – Anaesthesia for myotonic dystrophy