BMJ Case Notes 2009
Bites and Stings Redback spider antivenom used to treat envenomation by a juvenile Steatoda spider
MJA 1998; 169: 642
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To the Editor: Redback spider (Latrodectus hasselti)
envenomation is well documented, but little is known about the
equally common and closely related genus
Steatoda.1,2 Here, we report a
latrodectism-like syndrome caused by the bite of a juvenile brown
house spider (Stetoda sp.) which was treated with redback
spider antivenom (CSL Ltd, Melbourne, Vic.).
A previously healthy two-and-a-half-year-old child was bitten on sthe chin while playing outside with his mother in March 1998. The spider was later identified as a juvenile Steatoda, although the species was not determined (Catriona McPhee, Collection Manager, Entomology, Museum of Victoria, personal communication). The child complained of bite-site pain and local erythema was noted, but he seemed otherwise well. However, the next morning (22 hours after the bite) he was floppy, lethargic, excessively sweaty, irritable and shivering intermittently. He refused to eat or drink and vomited three times. Twenty-six hours after the bite he was taken to the local hospital emergency department, where he was noted to have a heart rate of between 120 and 140 beats per minute, a systolic blood pressure of 120 mmHg and to be very floppy. He was drowsy but rousable and seemed to be salivating excessively. Laboratory findings were unremarkable.
The spider (see Figure) had the globular abdomen of a female redback spider but lacked the familiar red stripe. In view of the latrodectism-like symptoms, the Australian Venom Research Unit medical advisory service recommended that the child be treated as for redback spider bite. Thus, after giving promethazine (7.5 mg intramuscularly) as a premedicant, the child was given one ampoule of redback spider antivenom (500 units, intramuscularly) 28 hours after the bite and a further ampoule two hours later. He was then transferred to the Royal Children's Hospital where, on admission, his hypertension and tachycardia had resolved, but he remained lethargic, floppy, irritable and drowsy, although he could converse with the examiner. The rest of the neurological findings were normal. A faint reticular erythematous rash was visible below the chin spreading towards the back of the neck. This area also seemed tender on palpation, without lymphadenopathy. Full examination revealed no other cause for his condition, which improved, allowing discharge home 48 hours after the bite. In-vitro studies on Steatoda venoms have reported stimulation of excessive neurotransmitter release reminiscent of the Latrodectus spider venom component a-latrotoxin.3,4 Consistent with this, local pain, sweating and malaise have been attributed to bites from female Steatoda species.1,2 This case shows the potential toxicity of Steatoda venom in children and suggests that redback spider antivenom may have a place in the management of envenomation by these species. Further research is clearly warranted.
Mike South Peter Wirth Ken D Winkel
The Australian Venom Research Unit medical advisory service can be contacted by telephone (03 9344 7753) or e-mail <avruATpharmacology.unimelb.edu.au>
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