When to worry about spider bites. Inaccurate diagnosis can have serious, even fatal, consequences

Almost all species of spiders are capable of biting people, but the bites of only a few are medically significant. Physicians need to be able to recognize the clinical signs and symptoms of common venomous spider bites and administer appropriate therapy. This may be difficult, since the offending spider is rarely seen or recovered for identification. Knowledge of life cycles, habits, and toxicity of venomous spiders enables physicians to provide more comprehensive medical care of bite victims. It is hoped that study of immunologic mechanisms and inflammation mediators will lead to the development of new treatments.

Spider bite. A rational approach

BACKGROUND

Spider bite is one of the most common envenomation problems in Australia. Australia is home to two spiders of major medical importance; the Sydney funnel web spider and the redback spider.

OBJECTIVE

This paper describes the features of envenomation and discusses treatment for bites by the Sydney funnel web spider and the redback spider. Bites by other spiders are also discussed, as is the problem of necrotising arachnidism.

DISCUSSION

It is hoped that the information contained within this article will be of help to medical practitioners dealing with spiderbite throughout Australia. There is, as yet, a great deal to be learned about spiderbite, particularly necrotising arachnidism.

Widow spider envenomation (latrodectism): a worldwide problem

The objective of this study was to review widow spider envenomation on a worldwide basis, with an emphasis on regional variability in management, particularly between the United States and Australia. Data sources were the Medline database (1966-1997) for English language references using as key words widow spider, latrodectism, and red back spider, and Mesh headings. Textbooks of toxinology were also used. Studies involving clinical reports and series were selected. The data indicated that envenomation by widow spiders (latrodectism) is common worldwide. Local pain and sweating predominate, in about 25% of cases becoming generalized or developing in remote sites. The mortality in published series varies from 5% to 10%, although these may be overestimates. Australia may have the highest rate of latrodectism in the world. The literature reveals regional disparities in the treatment and outcome of latrodectism. In Australia, intramuscular antivenin has been used liberally for more than 40 years with a very low rate (0.5% to 0.8%) of allergic reactions and no deaths recorded since its introduction. Antivenin is routinely successful in relieving the effects of latrodectism. In the United States, the antivenin is given intravenously, is usually reserved for very severe cases, and the rate of allergic reaction is high (from 9% up to 80% in those skin testing positive). Deaths have been recorded after antivenin. The literature suggests that antivenin to one species of Latrodectus is likely to be effective against other species. The conclusion drawn was that latrodectism is a common envenomation worldwide. There is a strong case for a comparative trial of Australian vs US antivenin in treating latrodectism due to the black widow spider in the United States.

Loxosceles arizonica bite associated with shock

Envenomation by the brown recluse spider (Loxosceles reclusa) is associated with shock, significant hemolysis, renal insufficiency, and disseminated intravascular coagulation (DIC). Shock has never been associated with envenomation by L arizonica, a related species indigenous to Arizona, southern California, and northwestern Mexico. We report the case of a 13-year-old girl, bitten by a specimen of L arizonica (the spider was identified by an entomologist), in whom shock and a typical cutaneous lesion developed. She did not experience renal insufficiency or disseminated intravascular coagulation. Infectious causes of shock were excluded. She recovered completely with supportive care.

Near fatal envenomation from the funnel-web spider in an infant

Children with significant envenomation require early first aid, resuscitation, and the administration of antivenom at the earliest possible time to survive. The case of a nine-month-old infant with life-threatening massive envenomation from the Sydney funnel-web spider (Atrax robustus) is presented. The infant was administered life-saving first aid (pressure immobilization bandage) and resuscitation measures prior to and during the administration of funnel-web-specific antivenom. The infant was discharged two days after the initial envenomation, without sequelae from the envenomation or antivenom. The survival of this infant is attributed to the immediate use of first aid, together with aggressive supportive measures and the administration of repeated doses of specific antivenom.

[Poisoning from spider bites. How to treat]

Three types of poisonous spiders that inhabit the Iberian Peninsula are discussed. How to identify these spiders and the type of venom they inject are described. Symptoms and specific treatments, both in the field and in the hospital, are listed.

Clinical presentation and outcome of brown recluse spider bite

STUDY OBJECTIVE

To examine the clinical presentation and outcome of patients treated in the ED or toxicology clinic for suspected brown recluse spider bites.

METHODS

We assembled a retrospective case of patients at a southeastern US university hospital. Our study group comprised 111 patients with suspected brown recluse spider bites treated during a 30-month period. Our main outcome measures were the need for skin grafting and the development of other complications.

RESULTS

The mean age of our subjects was 34 +/- 17 years. Thirteen patients (12%) brought the spider to the hospital, 22 (20%) saw a spider at the time of the bite, and an exclusively clinical diagnosis was made in the remaining 76 (68%). Most wounds (59%) involved the leg. At the time of presentation, 81% had central discoloration and 37% necrosis. Sixteen patients (14%) were systemically ill, and 6 (5%) were admitted to the hospital. Most (86%) were treated with antibiotics. Dapsone was infrequently used (9%) and had usually been prescribed before the patient's presentation to our ED. Only three patients (3%; 95% confidence interval, 1% to 8%) required grafting. Mild hemolytic anemia developed in one patient, and another had mild hemolysis and a mild coagulopathy; neither patient was taking dapsone. No deaths or serious complications occurred in our study group.

CONCLUSION

In our series, long-term outcome after brown recluse spider bite was good. Serious complications were rare, as was the need for skin grafting. Because the vast majority of bites heal with supportive care alone, aggressive medical therapy does not appear warranted.

A red-back spider bite in a lymphoedematous arm

We administered a record eight ampoules of antivenom over one week to a 55-year-old woman with a red-back spider bite on her chronically lymphoedematous right arm. She had severe local signs of envenomation but relatively little systemic effect. The final antivenom dose, injected subcutaneously at the bite site, had a good effect.

Spider bites in the United States

The bite of the brown recluse spider rapidly causes an infarction in skin that is painful and can be slow to heal. This is the only North American spider to cause such severe necrosis. The bite sometimes can produce a sudden, severe hemolysis. Conservative care without drugs is the safest proven treatment.

Effect of hyperbaric oxygen on sphingomyelinase D activity of brown recluse spider (Loxosceles reclusa) venom as studied by 31P nuclear magnetic resonance spectroscopy

Hyperbaric oxygen (HBO) has been reported by some to be therapeutic for necrotic lesions induced by the venom of the brown recluse spider, Loxosceles reclusa. Others have reported no efficacy for this treatment. In this study, the effect of high pressure oxygen on an enzymatic activity of the toxin of this venom is reported. The time course for the hydrolysis of the phosphocholine ester bond of chicken egg yolk sphingomyelin, as catalyzed by brown recluse spider venom (BRSV) and venom treated with extended HBO (12 hr at 10 atmospheres), was followed by phosphorus-31 nuclear magnetic resonance spectroscopy. The venom and HBO-pretreated venom demonstrated sphingomyelinase D activity. Phospholipase C activity was not detected. The sphingomyelinase D activity of BRSV in three separate experiments was not altered by HBO. The HBO-pretreated venom, in all cases, did not exhibit an altered time course in the overall hydrolysis of the D linkage of sphingomyelin.

Brown recluse spider envenomation: a prospective trial of hyperbaric oxygen therapy

OBJECTIVES

Loxosceles reclusa (brown recluse) spider bites can produce severe skin lesions that may necessitate extensive surgical repair. This study delineated the effects of hyperbaric oxygen (HBO) therapy on these lesions by performing a prospective controlled animal study.

METHODS

After approval by the Institutional Animal Care and Use Committee, 41 New Zealand white rabbits received 64 intradermal injections of 73 microL of raw venom extract mixed with physiologic buffered saline (Dulbecco's solution). Control injections were made with buffer. The animals were divided into 5 groups: 1) venom and no HBO; 2) venom and 1 immediate HBO treatment (100% O2); 3) venom and immediate HBO with 10 treatments (100% O2); 4) venom and then delayed (48 hr) HBO therapy with 10 treatments (100% O2); and 5) venom and immediate hyperbaric treatment with normal inspired PO2 for 10 treatments (8.4% O2). Three animals in group 2 also received a control sodium citrate buffer injection. HBO treatments were at 2.5 atm absolute (ATA) for 90 minutes twice daily. Daily measurements were made of the lesion diameter, and skin blood flow using a laser Doppler probe.

RESULTS

There was no significant effect of HBO on blood flow at the wound center or 1-2 cm from the wound center. Standard HBO significantly decreased wound diameter at 10 days (p < 0.0001; ANOVA), whereas hyperbaric treatment with normoxic gas had no effect. Histologic preparations from 2 animals in each group revealed that there were more polymorphonuclear leukocytes in the dermis of all the HBO-treated animals when compared with the venom-alone and sodium-citrate controls.

CONCLUSION

HBO treatment within 48 hours of a simulated bite from L. reclusa reduces skin necrosis and results in a significantly smaller wound in this model. The mechanism appears unrelated to augmented local blood flow between treatments.

Upper airway obstruction caused by brown recluse spider envenomization of the neck

A 7-year-old boy presented to the emergency department with progressive cervical soft tissue swelling and airway compromise due to envenomization by a brown recluse spider. This life-threatening complication is an extremely unusual presentation of brown recluse spider envenomization. Previous published reports have centered on the disfiguring localized tissue necrosis or life-threatening systemic reactions that occur secondary to the spider's venom.

The black widow: is she deadly to children?

Pediatric cases of black widow spider envenomation (BWSE) were reviewed in order to assess the morbidity and mortality in children with BWSE, and to make recommendations for optimal therapy. The methodology includes a retrospective chart review in an urban pediatric tertiary care hospital. Included were all pediatric patients admitted with the BWSE diagnosis in the last 10 years (1984-1994). The results are based on 12 children with ages ranging from 15 months to 18 years. The BWSE syndrome is characterized by several common systemic effects. Our cases revealed abdominal pain (100%), hypertension (92%), muscle complaints (75%), a target lesion (75%), and irritability/agitation (66%) as the most common symptoms. Treatments used included antivenin, calcium gluconate, benzodiazepines, and opioids. Eight of 12 patients recovered (had relief of symptoms) within 24 hours, often by 12 hours. Antivenin did appear to bring quicker relief of symptoms. Hypertension was severe but asymptomatic in all patients. There were no complications or deaths resulting from BWSE.

Management of snake and spider bite in pregnancy

The fact that venomous snakebites during pregnancy result in a high fetal wastage and that both venomous snake and spider bites may cause maternal mortality, makes this an important, albeit uncommonly encountered, entity in obstetrics. Perhaps the most difficult aspect of dealing with this clinical situation is that care must be rendered simultaneously to two patients with a complex interrelationship. The object is to optimize maternal care and increase the chances of successful pregnancy. Adherence to the tenet that what is best for the mother is best for the fetus will probably produce the most satisfactory outcome.

Management of the brown recluse spider bite to the glans penis

A significant number of people are bitten by the brown recluse spider (BRS) each year. Medical treatment regimens are sometimes unsatisfactory and surgical intervention is often necessary to debride the necrotic wound. This case study reports the treatment given to a 19-year-old active duty United States Army soldier who suffered a BRS bite to the glans penis. This patient received immediate medical attention and was started on intravenously administered diphenhydramine, methylprednisolone, calcium gluconate, and famotidine. Oral dapsone treatment was begun in the emergency room. Within 24 hours after his injury, the patient received his first hyperbaric oxygen treatment, which was continued twice daily for 5 days. Skin necrosis was avoided, the patient did not require any surgical intervention, and he was discharged after 8 days without sequelae.

Comparison of hyperbaric oxygen and dapsone therapy for loxosceles envenomation

OBJECTIVE

To determine whether hyperbaric O2 (HBO), dapsone, or HBO plus dapsone affects lesion size in a swine model of Loxosceles envenomation.

METHODS

In a randomized controlled animal laboratory experiment, 32 piglets were assigned to 1 of 4 equal groups. Each piglet received 15 microliters, of purified venom intradermally on day zero. Group 1 received no treatment; group 2 received HBO at 2 atm for 2 hours on days 1-3; group 3 received 50 mg of dapsone orally on days 1-3; and group 4 received dapsone 50 mg orally and HBO at 2 atm for 2 hours on days 1-3. On days 1-7, 14, and 21, an investigator blinded to the treatment groups measured necrosis and induration. Mean necrosis and induration rates were compared using analysis of variance for repeated measures.

RESULTS

Comparing groups on any day, no significant difference was noted in necrosis, induration, reduction in necrosis from day 1, or rate of change in lesion size from days 1-7. A difference was seen in the reduction of induration between all 3 treatment groups and the control group on days 7 and 14 only. The sample size permitted a power of 0.8 to detect a 12-mm mean change in lesion size.

CONCLUSION

Compared with the control, neither dapsone, HBO, nor the combination of dapsone and HBO reduced necrosis from Loxosceles envenomation on days 3-21. An increase was seen in the rate of reduction in induration between all 3 treatment groups and the control group on days 7-21. However, the magnitude of this effect was clinically insignificant. In this animal model, treatment with either dapsone or HBO or a combination offers little clinical benefit in Loxosceles envenomation.

Treatment of snake, insect, scorpion, and spider bites in the pediatric emergency department

Most people seem to have a visceral fear of snakes, spiders, scorpions, and insects out of proportion to the actual danger they pose. The vast majority of bites and stings cause little more than local pain and never require medical attention. Nevertheless, physicians who work in the emergency department must be prepared to treat the few patients who present with anaphylactic reactions to Hymenoptera stings, as well as to recognize and treat those rare individuals who receive severe envenomation from poisonous snakes, spiders, or scorpions.