Severe Sydney funnel-web spider envenomation in a toddler: a case report

Abstract

Introduction Sydney funnel-web spider (Atrax robustus) envenomation produces overlapping catecholaminergic and cholinergic toxidromes that can progress rapidly to life-threatening cardiorespiratory compromise. Airway management in this setting carries unique pharmacodynamic challenges.Case A 2-year-old boy developed refractory generalised seizures, severe trismus, hypoxic and hypercapnic respiratory failure, and cardiogenic pulmonary oedema following a Sydney funnel-web spider bite. Seizures persisted despite two doses of midazolam. Rapid sequence intubation was complicated by prolonged trismus, consistent with the delayed onset of neuromuscular blockade in the setting of venom-induced excess synaptic acetylcholine. One vial of antivenom and supportive care resulted in full recovery without residual deficit.Discussion The persistent trismus likely reflected a combination of ongoing seizure activity, direct neuromuscular excitation, and competitive antagonism of rocuronium by excess acetylcholine. Clinicians managing funnel-web envenomation should anticipate these interactions and consider higher doses or alternative neuromuscular blocking agents.