Treatment of Hymenopteran Stings Matthew Tucker, D.O. Department of Emergency Medicine Hillcrest Medical Center Tulsa, OK

Distribution and Biology of Hymenopterans Order Hymenoptera represents the most developed form in class Insecta with regard to biology and behavior. One form or another is present in almost every environment on the planet. Their medical importance is underscored as they are responsible for the majority of venom related deaths in the US and Europe.

Stinging Apparatus Evolved from ovipositor to defensive tool in some species.

Medically Important Hymenoptera The order hymenoptera includes three families of medical importance: Vespidae (wasps)- include the yellow jackets, hornets, and red wasps. Apidae (bees)- honey bees and bumble bees Fomicidae (stinging ants)- include the fire ants

Honey bee

Yellow jacket

Paper wasp

Clinical Toxicology Introduction –The winged members of hymenoptera generally cause the most medical issues, though the fire ant (Solenopsis) may cause severe reactions Typically the amount of venom injected is low, most people are stung many times over their life thus causing a potential sensitization to venom components resulting in severe reactions to future stings. The earliest description of an insect sting fatality was found in the tomb of the Egyptian pharaoh Menes who died in 2621 BC.

Clinical Toxicology Composition of wasp and bee venoms –Low molecular weight substances Histamine- pain inducer, dilatation and permeability of capillaries at the sting site, urticaria, angioedema, and hypotension. Dopamine Tyramine Epi and norepinephrine

Clinical Toxicology Venom composition (con’t) –Peptides Various kinin-like peptides- associated with mast cell degranulation, responsible for most local effects. In bee venom, melittin is the peptide most associated with pain. Melittin breaks down the resting potential of the cell, thereby initiating the sensation of pain.

Clinical Toxicology Venom composition (con’t) –High molecular weight substances Phospholipases A2 and B Hyaluronidases (venom spreading component) DNAse Others

Clinical Aspects The various enzymes and vasoactive components induce a local inflammation in the region of the sting. If the sting is vascular, the venom can become systemic giving rise to more severe reactions. Patients with allergies to hymenoptera venom, only minute amounts of the allergen can initiate severe reactions. Systemic reactions are thought to be mediated by Ig-E.

Clinical Aspects Reactions –Local reaction occurs when there is swelling contiguous with the sting site. No systemic signs or symptoms exist.

Clinical Aspects Reactions -Toxic reaction usually with history of 10 or more stings. The symptoms resemble systemic reactions, however there is no bronchospasm or urticaria. Typically, GI symptoms predominant. May also include HA, fever, muscle spasms, etc.

Clinical Aspects Reactions –Systemic reaction may occur with single or multiple stings and may be mild to severe. Symptoms may include cough, urticaria, and flushing. They may progress to wheezing, GI sx, N/V, laryngeal stridor, syncope, shock, and bloody sputum. This may be fatal in as little as 30 min.

Clinical Aspects Delayed reaction -presents as a serum- sickness type of reaction. Includes fever, malaise, HA, polyarthralgias occurring days after the sting.

Treatment If stinger is still present (honeybee), scrape it out, do not squeeze. Local reactions may be treated with ice packs, OTC analgesics and antihistamines. For more significant swelling, prednisone (20 – 40mg daily) Systemic reactions may present as a rapidly changing clinical picture.

Treatment Systemic –Monitoring and ALS measures early. –If the clinical picture indicates, rapid administration of epinephrine (1:1000) 0.3 mL SQ (0.01mL/kg for children) is necessary. –Diphenhydramine 50 – 100mg IM/IV for urticaria and pruritis. –Nebulized albuterol for bronchospasm. Nebulized racemic epinephrine may be needed for laryngospasm. –IV Solucortef or Solumedrol

Treatment Systemic –Airway should be monitored closely and control should be gained early if necessary. –Crystalloid infusion for hypotension should be aggressive. If hypotension persists after fluid replacement, dopamine may be started. –IV hydrocortisone or methylprednisolone may help prevent delayed symptoms.

Prophylaxis and Long Term Management Skin testing and immunotherapy Personal rescue kits: Ana-Kit or Epi-Pen Medic alert bracelets

Sources: –Tintinalli, J., Emergency Medicine: A Comprehensive Study Guide, 3 rd Ed. –Meier J. and White J., Handbook of Clinical Toxicology of Animal Venoms and Poisons.

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