Examqo › Examqo library › Anesthesiology › Special populations · IMLE
Anaesthesia in neuromuscular disease
Every neuromuscular disease changes the response to relaxants and volatile agents: in myasthenia sensitivity to non-depolarisers, in Duchenne and myotonia succinylcholine is forbidden, and in Parkinson disease levodopa must not be stopped — and in all of them postoperative ventilation is planned for.
Why it matters in the exam
The exam asks about myasthenia gravis (sensitivity to non-depolarising relaxants, resistance to succinylcholine, continuing pyridostigmine, risk of prolonged ventilation), Lambert-Eaton syndrome and its link to lung cancer, Duchenne dystrophy (hyperkalaemic arrest with succinylcholine and rhabdomyolysis with volatile agents), myotonic dystrophy (prolonged contracture after succinylcholine and sensitivity to sedatives), and Parkinson disease and the antiemetics that must not be given.
In myasthenia there are fewer acetylcholine receptors, so a small dose of a non-depolarising relaxant paralyses, and succinylcholine needs a higher dose. Sugammadex allows reliable reversal of rocuronium. In conditions with nerve injury — spinal cord injury, Guillain-Barré, stroke with paralysis, prolonged immobilisation — new receptors spread along the muscle, and succinylcholine may cause fatal hyperkalaemia. Central core disease is linked to malignant hyperthermia.
In myotonic dystrophy succinylcholine causes a prolonged contracture that makes ventilation difficult, neostigmine may worsen the myotonia, and cold and shivering trigger contractions; there are also cardiac conduction defects and high sensitivity to opioids and sedatives. In Parkinson disease levodopa is continued until surgery and restarted quickly, because abrupt withdrawal may cause rigidity and an NMS-like syndrome; metoclopramide, droperidol and haloperidol are avoided. In all these diseases respiratory strength should be assessed and postoperative observation planned. In multiple sclerosis a rise in temperature is avoided, and in epilepsy antiepileptic drugs are continued until the morning and restarted quickly after surgery, to prevent a seizure.
Key points
- Myasthenia: sensitive to non-depolarisers, resistant to succinylcholine, continue pyridostigmine.
- Lambert-Eaton: sensitive to both types; lung cancer.
- Duchenne and myotonia: no succinylcholine.
- Nerve injury and immobilisation: hyperkalaemia with succinylcholine.
- Parkinson disease: do not stop levodopa; no dopamine blockers.
Summary table
| Disease | Muscle relaxants | Exam point |
|---|---|---|
| Myasthenia gravis | Sensitive to non-depolarisers; resistant to succinylcholine | Continue pyridostigmine; sugammadex helps |
| Lambert-Eaton | Sensitive to both types | Linked to small cell lung cancer |
| Duchenne and Becker | Succinylcholine forbidden; avoid volatile agents | Hyperkalaemic arrest; cardiomyopathy |
| Myotonic dystrophy | Succinylcholine forbidden; neostigmine may worsen | Sensitive to opioids; avoid cold and shivering |
| Parkinson disease | No special change | Do not stop levodopa; no metoclopramide or droperidol |
In the full version for subscribers
- A simple algorithm
- Memory aid
- Exam traps
- 5 review cards
- Enough for IMLE
The full version is open to subscribers of: Anesthesiology, Neurology, Pediatrics, Medical licensing exam (IMLE).
Subscriber? Read the full topic Plans and prices 25 free questions
Sources
- Miller's Anesthesia, 9th edition (2020) — Neuromuscular Disorders and Malignant Hyperthermia; Anesthetic Implications of Concurrent Diseases
- Morgan & Mikhail's Clinical Anesthesiology, 7th edition (2022) — Anesthesia for Patients with Neuromuscular Disease
Sources are given for further reading; the text is written afresh and not copied from them.
Reviewed by the Examqo AI Professor · 2026-11-02. The text may contain errors; when in doubt, check the source.