Bites, Stings, and Envenomations

1

A 60-year-old man was sweeping the floor of his garden shed when he was bitten by a large spider. He has managed to trap the spider under a glass jar. On arrival to his Houston, Texas, residence, you find him sitting on a chair anxiously holding his wounded left hand. You are unsure if the trapped spider is a black widow or brown recluse. How do these spider bites differ in presentation and management?

See Table 57.1 .

Table 57.1

Differentiating Between Brown Recluse and Black Widow Spider Bites

	BROWN RECLUSE	BLACK WIDOW
Source	South, Central, Midwest United States Prefer dark, warm, protected areas (closets and garages)	Throughout North America (except for Maine and Alaska) Most commonly in South, Ohio Valley, Southwest, and West Coast Attics, barns, trash piles
Description	Violin-shaped mark on the dorsal cephalothorax	Red hourglass-shaped marking on underside of the abdomen
Mechanism of action	Cytotoxic Usually only bite when threatened	Affects neurotransmitters
Clinical manifestation	Stinging sensation Increased pain and pruritus within hours Mild local irritation leading to large necrotic lesions Loxoscelism: systemic reaction (40% of envenomations most common in young children): fever, nausea/vomiting, headache, arthralgias, morbilliform eruption with petechiae, hematuria, and renal failure	Local reaction Latrodectism : widespread, sustained muscle spasms/pain; tachycardia, diaphoresis, flushing, hypotension, “pavor mortis” (fear of death), grimaced face, conjunctivitis/rhinitis, periorbital edema Myopathic syndrome : muscle cramps at the site of the bite, progression to muscle rigidity of large skeletal muscles (chest, abdomen, face); may mimic an acute abdomen
Treatment	Supportive (pain control, local wound care, elevation) AVOID early excision Antibiotics if secondary wound infection Tetanus	Stabilize ABCDEs Pain/muscle spasm management: benzodiazepine, opioids AVOID beta-blockers Severe envenomation may require antivenin (rare)

All images © iStock.

2

A 6-year-old girl was playing in her yard when she felt a sharp sting on her right arm and looked down to see a scorpion scurry away. You are called for further management given the severity of pain. What do you know about scorpion envenomation that you could share with the parents?

In the United States, the vast majority of scorpions reside in the Southwest (Arizona, California, Nevada, New Mexico, and Texas). Venom is contained in the tail and has neurotoxic and cytotoxic properties. Fatality is rare from scorpion stings, but symptoms can be severe. The smaller sized scorpions can be the most venomous. Scorpion stings are most commonly seen in young children.

3

Describe the clinical manifestations of scorpion stings and how they are classified.

• Clinical manifestations of envenomation vary widely:

  • Grade I: Local pain, burning, and paresthesia at the sting site

  • Grade II: Local AND remote pain with paresthesia

  • Grade III : Either neuromuscular hyperactivity or cranial nerve dysfunction

  • Grade IV: Both neuromuscular hyperactivity and cranial nerve dysfunction

• Neuromuscular/systemic symptoms may include:

  • Shaking/jerking of extremities, fasciculations, restlessness

  • Roving eye movements, slurred speech, tongue fasciculations, hypersalivation, upper airway dysfunction

  • Difficulty swallowing, tachycardia, hypertension, vomiting, stridor, hypoxia, respiratory distress, fever and/or anaphylaxis, development of pancreatitis

4

What are your next steps in the management of this patient?

• Stabilize the ABCDEs

• Grade I + II envenomations can be managed with ibuprofen and acetaminophen.

• Grade III + IV envenomations require hospital care.

  • Secure the airway and ensure appropriate oxygenation.

  • Focus on pain control and excessive motor activity.

    • Oral/intravenous (IV) narcotics, benzodiazepines

  • Vomiting

    • Usually transient and self-limited

    • Consider antiemetics such as ondansetron

  • Hypersalivation

    • Atropine

  • Antivenin

    • Consider use for Grade III + IV envenomation.

5