A 30-year-old man with 40% body surface area flame burns sustained three days ago requires emergency intubation. The anaesthetist considers succinylcholine for rapid sequence induction. What is the principal concern?

• A Malignant hyperthermia triggered specifically by denervation injury
• B Bradyarrhythmia from vagal stimulation of the burned airway
• C Prolonged apnoea due to pseudocholinesterase deficiency induced by the burn
• D Severe hyperkalaemia from proliferation of extrajunctional nicotinic receptors ✓

Explanation

After major burns (and any denervating injury), extrajunctional nicotinic receptors proliferate across the muscle membrane beyond the motor end plate. Succinylcholine depolarises this expanded receptor population, causing massive potassium efflux and potentially fatal hyperkalaemia, a risk that begins roughly 48 hours after injury. Pseudocholinesterase levels actually fall after burns, but this is not the principal concern here and malignant hyperthermia is unrelated to denervation.

Reference: Katzung Basic and Clinical Pharmacology, 15th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.