Funnel-web spider (Hadronyche infensa) envenomations in coastal south-east Queensland

Five patients with confirmed funnel-web spider bites (Hadronyche infensa) presented to Nambour General Hospital, in south-east Queensland, between 1992 and 1998. Two patients required antivenom; low doses of antivenom were effective. Patients were bitten in spring and early summer. In areas such as this, where funnel-web spider bites are reported less frequently than in New South Wales, clinicians and the community should be aware of the risks and immediate management of these bites.

Anthony P Harrington, Robert J Raven, Paul C Bowe, Gabrielle M Hawdon and Kenneth D Winkel

MJA 1999; 171: 651-653

Introduction - Clinical record - Discussion - Acknowledgements - References - Authors' details
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We reviewed the records of proven funnel-web spider bites in patients presenting to Nambour General Hospital, Queensland, between 1992 and 1998. The clinical records of two of these patients are presented, and all are summarised in the Table.

Patient 1
A healthy young woman was bitten on her right middle finger by a spider while working in her garden in November. She rapidly developed numbness around her mouth and tongue and noted a painful red bite site. Her local doctor applied pressure-immobilisation first aid and transferred her to Nambour General Hospital.

On arrival, one and half hours later, she complained of generalised paraesthesiae, with neck and jaw muscle spasm, as well as blurred vision. Physical examination revealed fasciculation of the tongue, but otherwise her vital signs were normal. She was given 250 units of funnel-web antivenom, with intravenous premedication of promethazine 25 mg and hydrocortisone 100 mg. This resulted in rapid resolution of symptoms and signs, apart from persisting pain at the bite site.

She was admitted for observation and discharged the following day. The finger remained indurated and red for about 2 weeks. The captured spider was identified at the Queensland Museum as a male H. infensa (QMS 20633).

Patient 4
Early one November morning the father of a previously healthy 8-month-old boy found his child to be extremely lethargic, listless and covered in vomit. He had two puncture marks over the dorsal web space of the right third and fourth fingers. A large black hairy spider was found in the bed and captured for identification. The infant was taken immediately to the local country hospital and vomited on arrival. On admission, the infant was sweating profusely, and had increased salivation and lacrimation as well as generalised piloerection and tongue fasciculation. He was extremely lethargic with unreactive pinpoint (1 mm) pupils; respiratory rate 40/min; oxygen saturation, measured by pulse oximetry (Sao₂), 99% (fraction of inspired oxygen [Fio₂], 0.21); pulse rate 160 beats/min; and blood pressure 90/50 mmHg. Intermittent, isolated myoclonic jerks were observed.

Given the possibility of funnel-web spider envenomation, and because no antivenom was available at the hospital, the Sunshine Coast Retrieval Service was consulted. A helicopter responded immediately with an emergency physician and emergency nurse, together with four ampoules of funnel-web spider antivenom.

Almost four hours after the bite, the infant's conscious state had deteriorated, with minimal response to painful stimuli during intravenous cannulation. Antivenom premedication of adrenaline 0.1 mg intramuscularly, combined with hydrocortisone 30 mg and promethazine 5 mg, was given intravenously. The on-call toxinologist at the Australian Venom Research Unit advised treatment with two ampoules of antivenom. After the first ampoule (125 units intravenously over 10 minutes), the infant showed rapid and almost complete recovery. Within minutes of treatment he sat up, smiled and began to interact with his parents and hospital staff. The profuse sweating settled and his pupils dilated to 3 mm, with a brisk response to light. His pulse rate dropped to 130 beats/min and all other vital signs were normal.

He was then transferred by helicopter 100 km to the Brisbane Royal Children's Hospital Paediatric Intensive Care Unit, where he was observed overnight and discharged without further sequelae. The live spider was identified by the Queensland Museum as a male H. infensa (QMS 42731).

Pressure-immobilisation first aid was used in most cases (an improvement on the situation reported in the last series of bites reported in the Journal¹). This may have reduced the severity of the envenomation through local inactivation of the neurotoxin.⁴ Our patients presented with the classical features of funnel-web spider toxicity, including bite site pain, nausea, pupillary effects, piloerection, muscle fasciculation, hypertension, confusion, hypersalivation and lacrimation. However, we confirm that some funnel-web spider bite victims do not develop severe constitutional symptoms;^1,3,5 only two of our five patients required antivenom.

The outcome of any funnel-web spider bite is unpredictable, but the severity of the envenomation observed in our series appears be less than that associated with some of the other funnel-web species.^1,3,5 A larger series would be required to confirm the relative toxicity of H. infensa venom. Preliminary experimental results on female H. infensa venom implied a toxicity at least equivalent to that of male Atrax robustus venom.⁵ It is possible that the H. infensa spider bite may be a relatively "dry" or "let me go" defensive bite, and these spiders appear to be less aggressive, both in captivity and in the wild, than Atrax robustus (unpublished observations by R J R). The comparative composition of funnel-web venoms is being investigated.⁶ Our report confirms the initial impression⁷ that A. robustus antivenom appears to rapidly neutralise H. infensa venom.

No confirmed cases of H. formidabilis envenomation presented to Nambour Hospital, despite this spider living in the Sunshine Coast hinterland. However, unlike H. infensa, female H. formidabilis spiders live on tree trunks and in the rainforest canopy. However, male and female H. formidabilis spiders have been found on the ground and pose a risk to campers and timber industry workers. By contrast, both male and female H. infensa spiders build long silk retreats in the ground, usually near a tree. From October to April, and especially during November and December, the male spider wanders in search of a mate. At this time the chance of interaction with people is highest. Indeed, to date, all reported male H. infensa bites have occurred during these two months.

From an injury-control perspective, people living in funnel-web-spider-endemic regions should be particularly vigilant during early summer. The use of gloves when gardening may reduce or eliminate bite-induced morbidity. Unfortunately, bites also occur inside houses while victims are asleep. It is recommended that bedclothes and towels be kept off the ground. These spiders cannot climb smooth-painted wood or metal bed legs, but can easily climb bedding, which should be inspected before sleep, especially during summer.

1. Dieckmann J, Prebble J, McDonogh A, et al. Efficiency of funnel-web spider antivenom in human envenomation by Hadronyche species. Med J Aust 1989; 151: 706-707.
2. Gray M. Distribution of funnel-web spiders. In: Covacevich J, Davie P, Pearn J, editors. Toxic plants and animals: a guide for Australia. Brisbane: Queensland Museum, 1987: 319.
3. Hartman L, Sutherland S. Funnel-web spider (Atrax robustus) antivenom in the treatment of human envenomation. Med J Aust 1984; 141: 796-799.
4. Sutherland S, Duncan A, Tibballs J. Local inactivation of funnel-web spider (Atrax robustus) venom by first aid measures: potentially lifesaving part of treatment. Med J Aust 1980; 2: 435-437.
5. Sutherland S. Genus Atrax Cambridge, the funnel-web spiders. In: Australian animal toxins: the creatures, their toxins and care of the poisoned patient. Chapter 20. Melbourne: Oxford University Press; 1983: 255-298.
6. Wilson D, Alewood P. HPLC/ES-MS fingerprinting of Australian funnel-web spider (genus Atrax and Hadronyche) venoms. In: From venoms to drugs. Inaugural conference abstract book, Heron Island, Queensland, Australia: 16-21 August 1998. Brisbane: University of Queensland, Centre for Drug Design and Development, 1998.
7. Sutherland SK. Antivenom to the venom of the male Sydney funnel-web spider Atrax robustus: Preliminary report. Med J Aust 1980; 2: 437-441.

(Received 6 Sep, accepted 20 Oct, 1999)

Queensland Museum, Brisbane, QLD.
Robert J Raven, BSc, PhD, Museum Scientist (Arachnology).

Department of Emergency Medicine, Gold Coast Hospital, Southport, QLD.
Paul C Bowe, MB BS, FACEM, Emergency Physician.

©MJA 1999
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