The protocol for Envenomation (Insect/Arthropod):Envenomation insects
Let’s break it down!
Under the insect umbrella, this protocol focuses on two groups of bugs in particular: Hymenoptera and Arthropods.
Consists of bees, wasps, hornets, as well as some wingless creatures like fire ants. This group of insects is responsible for the majority of severe-sting related reactions. Hymenoptera generally only sting people in self-defense or to protect their nests or hives. Identifying the particular species of Hymenoptera responsible for stinging you can be difficult since most lesions appear the same, but looking for a nearby nest can help identify the critter responsible.
Consists of spiders, specifically the widow and recluse spiders that can be problematic to humans. These spiders are found worldwide, but heavier in North and South America. The brown recluse can be identified by it’s thick, brown body with occasional distinct violin markings on the head. Black widows usually have jet-black bodies with a red hourglass pattern on them.
Initial symptoms from bee/wasp stings are usually nothing crazy; some erythema, swelling, and maybe an identifiable puncture site. About 10% of people will experience severe localized reactions though, which can occur over a few days and result in even greater redness and swelling. Full anaphylaxis (allergic reaction w/ airway compromise, hypotension, etc.) only occurs in less than 3% of stings. The video below shows a gentleman showing his severe reaction from a yellow jacket:
Most spider bites will initially be painless or give off a pinprick sensation around the site that spreads to the rest of the extremity. Within a few hours, it may become red, swollen, and give off a burning sensation. If it is a brown recluse spider, you can expect it to become severely discolored and even grow a necrotic base over 3-4 days. For black widow bites, 1/3 of patients will experience systemic symptoms are common which include nausea/vomiting, hypersalivation, hypertension, and muscle spasms. Below is a video showing a compilation of spider bite injuries:
If signs and symptoms of anaphylaxis present, treat per Anaphylaxis protocol
Anaphylaxis is statistically rare, but still always a possibility for soldiers; especially if they already have a known allergy to bees/wasps. Treatment from the anaphylaxis protocol includes epinephrine, antihistamines, and steroids.
Remove stinger by scraping from side
The venom from the stinger is typically released within the first several seconds after the sting so if the insect or stinger can be flicked off of the skin immediately, it may help limit the amount of venom injected. However, if the patient presents minutes later, immediate stinger removal is not critical, because the venom will have already been fully expelled. Still, if venom is still in the stinger, a good way to decrease the possibility of accidentally squeezing more into the patient is to scrape it off with something like a credit card.
Apply ice or cold water
This will help reduce the inflammation in the area, thus reducing the patient’s pain.
Apply topical 1% Hydrocortisone cream
Hydrocortisone cream is a topical steroid that you can apply to the wound site to reduce inflammation. Not curative by any means, but may help the pain or itchiness
Apply topical lidocaine
Lidocaine is an anesthetic that may help numb the affected area, reducing the pain. If available, your patient will appreciate you using this.
Ibuprofen (Motrin) 800mg PO tid x 7 days
Ibuprofen, as most know, is an analgesic and anti-inflammatory. Since the venom often continues to cause swelling over several days, ibuprofen can help blunt this.
Diphenhydramine (Benadryl) 25-50mg q6hr prn PO/IV
Diphenhydramine is an antihistamine that can help control any potential allergic reactions from the sting, as well as control any pruritus (itchiness)
Elevate the bite site and avoid strenuous activity
This may help with inflammation, but the effectiveness elevating the bite site is unclear. Should not be routinely recommended.
Treat per Pain Management protocol (narcotic analgesia)
Spider bites, especially black widow bites, are notorious for causing severe pain. From the pain management protocol, opiates like Morphine and Fentanyl may be needed in addition to NSAIDS/Tylenol.
Diphenhydramine (Benadryl) 25-50mg q6hr prn PO/IV
Just like for bee/wasp stings, diphenhydramine may help control allergic reactions from the bite.
Diazepam (Valium) 2-10mg PO q6-8hr or 5-10mg IV/IM, if muscle spasms occur
On rare occasions, muscle spasms may occur following envenomation. Diazepam is one of many benzodiazepines that can be used to reduce the frequency and severity of the spasms.
Use an antibiotic appropriate for MRSA if cellulitis occurs
If you watched the spider bite compilation video, you noticed that the doctor was frequently concerned about cellulitis, an infection of the skin. Any time there is a puncture of the skin, cellulitis is a possibility. The cellulitis protocol recommends a regimen of antibiotics that includes TMP-SMZ (Septra), which will cover for methicillin-resistant Staph. aureus (MRSA).
Evacuation to higher care is typically not required so long as symptoms can be managed and the soldier can return to the fight. Some brown recluse bites can cause necrosis of the surrounding tissue, which has, on rare occasions, led to a loss of that limb. This warrants at least a Routine evacuation. Urgent evacuation is warranted if any systemic symptoms occur from these bites or stings like anaphylaxis, global muscle spasms in the chest or abdomen, etc. These patients will likely require antivenom!
Good luck out there!
- UpToDate: Management of widow bites
- UpToDate: Approach to the patient with a suspected spider bite: An overview
- UpToDate: Bee, yellow jacket, wasp, and other Hymenoptera stings: Reaction types and acute management
- EMRAP: Arthropod bites/stings
- Advanced Tactical Paramedic Protocols Handbook. 10th ed., Breakaway Media LLC, 2016.