Funnel‐web spider bite: a systematic review of recorded clinical cases

Objective: To investigate species‐specific envenoming rates and spectrum of severity of funnel‐web spider bites, and the efficacy and adverse effects of funnel‐web spider antivenom. Data sources: Cases were identified from a prospective study of spider bite presenting to four major hospitals and three state poisons information centres (1999–2003); museum records of spider specimens since 1926; NSW Poisons Information Centre database; MEDLINE and EMBASE search; clinical toxinology textbooks; the media; and the manufacturer's reports of antivenom use. Data extraction: Patient age and sex, geographical location, month, expert identification of the spider, clinical effects and management; envenoming was classified as severe, mild–moderate or minor/local effects. Data synthesis: 198 potential funnel‐web spider bites were identified: 138 were definite (spider expertly identified to species or genus), and 77 produced severe envenoming. All species‐identified severe cases were attributed to one of six species restricted to NSW and southern Queensland. Rates of severe envenoming were: Hadronyche cerberea (75%), H. formidabilis (63%), Atrax robustus (17%), Hadronyche sp. 14 (17%), H. infensa (14%) and H. versuta (11%). Antivenom was used in 75 patients, including 22 children (median dose, 3 ampoules; range, 1–17), with a complete response in 97% of expertly identified cases. Three adverse reactions were reported, all in adults: two early allergic reactions (one mild and one with severe systemic effects requiring adrenaline), and one case of serum sickness. Conclusions: Severe funnel‐web spider envenoming is confined to NSW and southern Queensland; tree‐dwelling funnel webs (H. cerberea and H. formidabilis) have the highest envenoming rates. Funnel‐web spider antivenom appears effective and safe; severe allergic reactions are uncommon.