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Spider Envenomation, Funnel Web: Treatment & Medication

Author: Joe Alcock, MD, MS, Assistant Professor, Department of Emergency Medicine, University of New Mexico Health Sciences Center; Acting Chief, Emergency Medicine Service, New Mexico Veterans Affairs Health Care System
Contributor Information and Disclosures

Updated: Dec 4, 2008

Treatment

Prehospital Care

  • If possible and when expedient and safe, the spider should be killed and collected for identification.
  • A pressure immobilization bandage identical to that applied in the management of Australian snakebite should be applied immediately. The dressing prevents migration of venom via lymphatics to the central circulation. Simultaneous immobilization (with a splint and/or sling) diminishes the muscle-pump effect on lymphatics and venous flow. Tourniquets are to be avoided.
  • Pressure immobilization must be maintained until the patient arrives at a hospital where antivenom is available.
  • Supportive care, including cardiac and respiratory life support, should be performed as necessary and according to the advanced cardiac life support (ACLS) protocol.

Emergency Department Care

  • Most bites do not result in severe envenomation, although local pain at the site of the bite is common. When severe envenomation occurs, resuscitation measures and antivenin therapy should be instituted as necessary.
  • Funnel-web spider antivenom (CSL, Melbourne) is prepared by hyperimmunizing rabbits with the venom of A robustus. It has been effective in treating victims of a variety of species of Australian funnel-web spiders
    • Antivenom has been highly successful in the treatment of A robustus envenomation. Complete resolution of symptoms has occurred in 97% of patients treated with antivenom after confirmed funnel-web spider bites. Antivenom has been used successfully in pregnant women, breastfeeding women, and children.
    • Anaphylaxis is a risk when giving antivenom. In a recent review, adverse effects consistent with anaphylaxis occurred in 2 patients of 75 treated with antivenom. One patient of the 75 developed serum sickness within 7 days of administration of antivenom.1
  • Premedication with an antihistamine and steroid to prevent anaphylaxis may be considered. However, premedication with epinephrine is contraindicated because of elevated catecholamine levels induced by the venom. Administration of epinephrine is appropriate if anaphylaxis occurs.
    • Antivenom should be given in the ED or intensive care unit with close monitoring by medical and nursing staff. The initial dose of antivenom is 2 bottles intravenously, but most cases require 4 or more bottles.
    • Antivenom is indicated if any of the following are present:
      • Muscle fasciculation
      • Marked salivation or lacrimation
      • Piloerection
      • Significant tachycardia
      • Hypertension in a previously normotensive patient
      • Hypotension or shock
      • Dyspnea
      • Disorientation
      • Confusion
      • Depressed level of consciousness
  • As with any bite, ensure that tetanus immunization status is up to date.

Consultations

  • Referral to an intensive care specialist may be necessary in cases of moderate-to-severe envenomation.
  • Advice from an experienced toxicologist practicing in an endemic area (eg, Sydney, Newcastle) should be sought in all funnel-web spider bites.
  • The New South Wales Poisons Information Centre (emergency phone number, 61-2-9845-3111) has toxicologists available 24 hours a day.

Medication

Pharmacologic therapy is indicated for patients with severe envenomations.

Antivenin

This agent neutralizes the toxins from the spider bite.


Funnel-web spider antivenom

Freeze-dried IgG prepared from rabbit serum, reconstituted with water for injection, and dispensed in bottles of 125 Units. Should be administered only where appropriate resuscitation facilities are immediately available.

Adult

2 bottles (150 Units) initial; repeat in 15 min if no response

Pediatric

Administer as in adults

Pregnancy

C - Fetal risk revealed in studies in animals but not established or not studied in humans; may use if benefits outweigh risk to fetus

Precautions

Precautions are the same as for any antivenom; however, risks of anaphylaxis (and serum sickness) with funnel-web spider antivenin appear to be very low

Antihistamines

These agents prevent the histamine response in sensory nerve endings and blood vessels. They are more effective in preventing histamine response than in reversing it.


Diphenhydramine (Benadryl, Benylin, Bydramine)

Used for the symptomatic relief of allergic symptoms caused by histamine released in response to allergens.

Adult

25-50 mg PO q6-8h prn; not to exceed 400 mg/d
10-50 mg IV/IM q6-8h prn; not to exceed 400 mg/d

Pediatric

12.5-25 mg PO tid/qid or 5 mg/kg/d PO or 150 mg/m2/d PO divided tid/qid; not to exceed 300 mg/d
5 mg/kg/d IV/IM or 150 mg/m2/d IV/IM divided qid; not to exceed 300 mg/d

Potentiates effect of CNS depressants; because of alcohol content, do not give syrup dosage form to patients taking medications that can cause disulfiramlike reactions

Pregnancy

B - Fetal risk not confirmed in studies in humans but has been shown in some studies in animals

Precautions

May exacerbate angle-closure glaucoma, hyperthyroidism, peptic ulcer, and urinary tract obstruction

More on Spider Envenomation, Funnel Web

Overview: Spider Envenomation, Funnel Web
Differential Diagnoses & Workup: Spider Envenomation, Funnel Web
Treatment & Medication: Spider Envenomation, Funnel Web
Follow-up: Spider Envenomation, Funnel Web
Multimedia: Spider Envenomation, Funnel Web
References
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References

  1. Isbister GK, Gray MR, Balit CR, Raven RJ, Stokes BJ, Porges K, et al. Funnel-web spider bite: a systematic review of recorded clinical cases. Med J Aust. Apr 18 2005;182(8):407-411. [Medline]. [Full Text].

  2. Isbister GK, Gray MR. Bites by Australian mygalomorph spiders (Araneae, Mygalomorphae), including funnel-web spiders (Atracinae) and mouse spiders (Actinopodidae: Missulena spp). Toxicon. 2004;43(2):133-40. [Medline].

  3. Fisher MM, Carr GA, McGuinness R, Warden JC. Atrax robustus envenomation. Anaesth Intensive Care. Nov 1980;8(4):410-20. [Medline].

  4. Dieckmann J, Prebble J, McDonogh A, Sara A, Fisher M. Efficacy of funnel-web spider antivenom in human envenomation by Hadronyche species. Med J Aust. Dec 4-18 1989;151(11-12):706-7. [Medline].

  5. Harrington AP, Raven RJ, Bowe PC, Hawdon GM, Winkel KD. Funnel-web spider (Hadronyche infensa) envenomations in coastal south-east Queensland. Med J Aust Med J Aust. Dec 6-20 1999;171(11-12):651-3. [Medline]. [Full Text].

  6. Howarth DM, Southee AE, Whyte IM. Lymphatic flow rates and first-aid in simulated peripheral snake or spider envenomation. Med J Aust. Dec 5-19 1994;161(11-12):695-700. [Medline].

  7. Sutherland SK. The Sydney funnel-web spider (Atrax robustus). 3. A review of some clinical records of human envenomation. Med J Aust. 1972;2:642-6.

  8. Sutherland SK, Duncan AW. New first-aid measures for envenomation: with special reference to bites by the Sydney funnel-web spider (Atrax robustus). Med J Aust. Apr 19 1980;1(8):378-9. [Medline].

  9. Sutherland SK, Duncan AW, Tibballs J. Local inactivation of funnel-web spider (Atrax robustus) venom by first- aid measures: potentially lifesaving part of treatment. Med J Aust. Oct 18 1980;2(8):435-7. [Medline].

  10. White J, Cardoso JL, Fan HW. Clinical toxicology of spider bites. In: Handbook of Clinical Toxicology of Animal Venoms and Poisons. CRC Press; 1995:272-83.

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Further Reading

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Keywords

funnel-web spider, funnel web spider, Sydney funnel web spider, spider bite treatment, spider bite symptoms, Atrax, Hadronyche, Atrax robustus, Hadronyche versuta, Hexathelidae, spider envenomation, spider bite, Australian funnel-web spider, delta-atracotoxins, robustotoxin, antivenom

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Contributor Information and Disclosures

Author

Joe Alcock, MD, MS, Assistant Professor, Department of Emergency Medicine, University of New Mexico Health Sciences Center; Acting Chief, Emergency Medicine Service, New Mexico Veterans Affairs Health Care System
Joe Alcock, MD, MS is a member of the following medical societies: American Academy of Emergency Medicine
Disclosure: Nothing to disclose.

Medical Editor

Robert L Norris, MD, Associate Professor, Department of Surgery; Chief, Division of Emergency Medicine, Stanford University Medical Center
Robert L Norris, MD is a member of the following medical societies: American College of Emergency Physicians, American Medical Association, California Medical Association, International Society of Toxinology, Society for Academic Emergency Medicine, and Wilderness Medical Society
Disclosure: Nothing to disclose.

Pharmacy Editor

John T VanDeVoort, PharmD, Regional Director of Pharmacy, Sacred Heart & St. Joseph's Hospitals
John T VanDeVoort, PharmD is a member of the following medical societies: American Society of Health-System Pharmacists
Disclosure: Nothing to disclose.

Managing Editor

Matthew M Rice, MD, JD, FACEP, Senior Vice President, Chief Medical Officer, Northwest Emergency Physicians; Assistant Clinical Professor of Medicine, University of Washington at Seattle
Matthew M Rice, MD, JD, FACEP is a member of the following medical societies: American College of Emergency Physicians, American Medical Association, National Association of EMS Physicians, Society for Academic Emergency Medicine, and Washington State Medical Association
Disclosure: Team Health  Salary Employment

CME Editor

John D Halamka, MD, MS, Associate Professor of Medicine, Harvard Medical School, Beth Israel Deaconess Medical Center; Chief Information Officer, CareGroup Healthcare System and Harvard Medical School; Attending Physician, Division of Emergency Medicine, Beth Israel Deaconess Medical Center
John D Halamka, MD, MS is a member of the following medical societies: American College of Emergency Physicians, American Medical Informatics Association, Phi Beta Kappa, and Society for Academic Emergency Medicine
Disclosure: Nothing to disclose.

Chief Editor

Jonathan Adler, MD, Attending Physician, Department of Emergency Medicine, Massachusetts General Hospital; Division of Emergency Medicine, Harvard Medical School
Jonathan Adler, MD is a member of the following medical societies: American Academy of Emergency Medicine and Society for Academic Emergency Medicine
Disclosure: eMedicine.com, Inc. Consulting fee Consulting

 
 
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