Page 68 - 2023 SMOG Digital

Environmental

Widow Spider Envenomation

Patients may or may not feel a pinprick upon the initial bite. A pair of small red spots at the envenomation site may be visible;
however, the bite site is often not located. Some patients do not develop systemic toxicity. In those patients who do, symptoms
typically begin 15 to 60 minutes following the envenomation. The primary symptom is painful muscle cramping, starting at the bite
site and progressing towards the center of the body. Patients may develop a painful, rigid abdomen secondary to abdominal muscle
spasm which may be mistaken for peritonitis. The pain increases over time and may occur in waves. In some cases, the patient
develops a temporary diaphoretic, grimaced, and contorted appearance of the face referred to as “facies latrodectismica.” Other
symptoms include vomiting, diaphoresis, tachycardia, hypertension (often profound), and restlessness. Symptoms of Latrodectus
envenomation last hours to days. Fatalities from Latrodectus envenomation are exceedingly rare and, when they do occur, are
secondary to cardiac arrest (presumably from severe hypertension in patients with predisposing medical conditions) and wound
infection.
Universal Patient Care Guideline Consider acetaminophen, NSAIDs, and
O2 (if Hypoxemic) Opioids:
IV/IO Guideline
IV/IO in non-effected limb Acetaminophen
Cardiac Monitor (prn) 1g PO prn q6–8hr max 4g in 24 hour
period
Allergic Reaction Guideline Allergic Reaction/AAnaphylaxis s Ketorolac
y
a
l
a
n
h
p
x
i
15mg IV q6hr
YES or 15–30mg IM q6hr,
–
NO
Consider benzodiazepines: max daily dose 120mg
Pain Management Guideline
Midazolam Fentanyl
2.5-5mg IV/IO 0.5–1.0mcg/kg IV/IO
every 15–30 prn 100mcg IN
or Severe muscle cramps/spasms? May repeat q30min
Diazepam YES or
5–10mg IV/IO; then 5–10mg in 3–4 PO 800mcg OTFC
–
hours, if necessary. NO or
Morphine
Nausea/Vomiting? 5mg (or 0.1 mg/kg) IV/IO q1–6hr prn
Consider: YES
Ondanestron
4-8mg IV/IO/IM/PO When appropriate, return to:
Tactical Evacuation Guideline
Pearls:
• Review country environmental concerns before deployment or visitation.
ENVIRONMENTAL
• Anaphylactic reactions should be treated as soon as recognized.
• Given the low risk of infection, antibiotics are not routinely recommended.
• Depending upon the severity of pain, acetaminophen, nonsteroidal anti-inflammatory agents, and
opioids can be used for pain control.
• Ketamine is not recommended as patients may develop tachycardia and have profound
hypertension due to widow spider toxin.
• Benzodiazepines may improve muscle spasms.
• Pain control and benzodiazepines are often sufficient to manage tachycardia and hypertension.
• Patients with severe pain refractory to pain medications, antivenom (if available) may be indicated,
evacuate to MTF where antivenom is available if able.
• Elevate effected limb to reduce swelling.
• DO NOT apply constricting bandages or tourniquets as these may worsen local tissue injury and
increase the risk of permanent disability.
• DO NOT cut, suck, electrocute, burn, or use chemicals on the envenomation site.

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