Spider Bite, Black Widow
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Basics
Description
- Syndromes caused by envenomation by black widow spider bite
- Mechanism of toxicity:
- Females are responsible for human envenomations
- Venom contains potent neurotoxin, α-latrotoxin:
- Causes cation-channel opening presynaptically, resulting in increased neurotransmitter release into synapses and neuromuscular junctions
- Increased neurotransmitter release causes increased neurologic, motor, and autonomic effects
- Morbidity and mortality are dose dependent
- Severity of envenomation depends on:
- Premorbid health of victim:
- HTN or cardiovascular disease increase risk
- Size and age of victim:
- Children (i.e., smaller size for a given dose of venom) are at greater risk of morbidity and mortality
- Number of bites
- Location of bite wounds
- Size and condition of spider
- Premorbid health of victim:
- Rarely fatal
Etiology
Black widow spider features:- Appearance:
- Glossy black with red markings shaped like an hourglass or a pair of spots on the ventral aspect of the globular abdomen
- Females have 25–50 mm leg spans and 15 mm long bodies
- Found throughout North America, except the far north and Alaska
- Prefer dark sheltered hideaways such as garages, barns, outhouses, woodpiles, and low-lying foliage
- Most bites occur during the warmer months when spiders are defending their webs and egg clutches
-- To view the remaining sections of this topic, please log in or purchase a subscription --
Basics
Description
- Syndromes caused by envenomation by black widow spider bite
- Mechanism of toxicity:
- Females are responsible for human envenomations
- Venom contains potent neurotoxin, α-latrotoxin:
- Causes cation-channel opening presynaptically, resulting in increased neurotransmitter release into synapses and neuromuscular junctions
- Increased neurotransmitter release causes increased neurologic, motor, and autonomic effects
- Morbidity and mortality are dose dependent
- Severity of envenomation depends on:
- Premorbid health of victim:
- HTN or cardiovascular disease increase risk
- Size and age of victim:
- Children (i.e., smaller size for a given dose of venom) are at greater risk of morbidity and mortality
- Number of bites
- Location of bite wounds
- Size and condition of spider
- Premorbid health of victim:
- Rarely fatal
Etiology
Black widow spider features:- Appearance:
- Glossy black with red markings shaped like an hourglass or a pair of spots on the ventral aspect of the globular abdomen
- Females have 25–50 mm leg spans and 15 mm long bodies
- Found throughout North America, except the far north and Alaska
- Prefer dark sheltered hideaways such as garages, barns, outhouses, woodpiles, and low-lying foliage
- Most bites occur during the warmer months when spiders are defending their webs and egg clutches
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