Black widow spider bite: Difference between revisions

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==Background==
==Background==
*Identification: red hourglass on otherwise black spider
*Genus: ''Latrodectus''
[[File:Western Black Widow (Latrodectus hesperus).jpg|thumb|Black widow spider]]
[[File:Western Black Widow (Latrodectus hesperus).jpg|thumb|Black widow spider]]
*Identification: red hourglass on otherwise black spider
*Genus: Latrodectus


===Mechanism===
===Mechanism===
Envenomation causes massive release of neurotransmitters norephedrine, dopamine, acetylcholine, glutamate and GABA from the nerve terminals causing muscle cramps, tachycardia and hypertension
*α-Latrotoxin envenomation causes massive release of neurotransmitters (norepinephrine, dopamine, acetylcholine, glutamate and GABA) from the nerve terminals muscle cramps, [[tachycardia]], [[hypertension]]
 
*This clinical envenomation syndrome is known as ''latrodectism''
The massive release of neurotransmitters leads to the clinical envenomation syndrome known as '''''latrodectism'''''.


==Clinical Features==
==Clinical Features==
 
===Local===
===Grading System===
*Grade 1: Range from no symptoms to local pain at the envenomation site with normal vital signs
*Grade 2: Involve muscular pain at the envenomation site to migration to the trunk, diaphoresis at bite site and normal vital signs
*Grade 3: Include grade 2 with abnormal vital signs; diaphoresis distant to envenomation site, generalized myalgias to back, chest and abdomen, nausea vomiting and headaches. 
 
===Local===  
*Pinprick sensation; then increasing local pain that may spread to entire extremity  
*Pinprick sensation; then increasing local pain that may spread to entire extremity  
*Erythema appears 20-60 min after the bite  
*Erythema appears 20-60 min after the bite  
*Pain begins to abate after several hours and disappears by 2-3d
*Pain begins to abate after several hours and disappears by 2-3d


===Systemic===  
===Systemic===
*Muscle cramp-like spasms in large muscle groups (although exam rarely reveals rigidity)  
*Muscle cramp-like spasms in large muscle groups (although exam rarely reveals rigidity)  
*Pain becomes generalized  
*Pain becomes generalized  
**Severe abdominal wall musculature pain and cramping
**Severe [[abdominal pain|abdominal wall musculature pain]] and cramping
*[[HA]], [[n/v]], diaphoresis, [[photophobia]], [[dyspnea ]]
**Difficult to differentiate from [[peritonitis]]
*[[Headache]], [[nausea/vomiting]], diaphoresis, photophobia, [[dyspnea]]
*[[A-fib]], [[myocarditis]], [[priapism]], and death are rare
*[[A-fib]], [[myocarditis]], [[priapism]], and death are rare
===Grading System===
*Grade 1: Range from no symptoms to local pain at the envenomation site with normal vital signs
*Grade 2: Involve muscular pain at the envenomation site to migration to the trunk, diaphoresis at bite site and normal vital signs
*Grade 3: Include grade 2 with abnormal vital signs; diaphoresis distant to envenomation site, generalized [[myalgia]] to back, chest and abdomen, nausea vomiting and headaches.


==Differential Diagnosis==
==Differential Diagnosis==
{{Bites and stings DDX}}
{{Bites and stings DDX}}


==Diagnosis==
==Evaluation==
*Typically clinical
*Generally clinical diagnosis


==Management==
==Management==
*Pain and muscle spasms
*Local wound care, [[analgesia]] and [[tetanus prophylaxis]] are mainstays of treatment 
**Grade 1:  Cold packs and NSAIDS
**Grade 1:  Cold packs and [[NSAIDs]]
**Grade 2/3: IV Opioids and Benzos
**Grade 2/3: IV [[Opioids]] and [[Benzodiazepines]]
*Systemic illness  
*[[Antivenin]] - indicated for systemic illness only
**Antivenin
**Dosage: Usual dose is one to two vials diluted in 50 to 100 mL 5% dextrose or 0.9% sodium chloride, then infused over 1 hour
***Controversial:  ''Morbidity'' (pain, cramping and autonomic disturbances) are high, but ''mortality'' is low.   The antivenin is horse serum derived, can lead to anaphylaxis and serum sickness.
**Use is controversial - ''Morbidity'' (pain, cramping and autonomic disturbances) are high, but ''mortality'' is low. Antivenin is horse serum derived, and can lead to anaphylaxis and serum sickness
***Consider for:  
**Consider for: Pediatric patients, pregnant women, elderly
****Children
 
****Pregnant women
===Not Indicated===
****Elderly
*Routine antibiotic use is not indicated
*IV [[calcium gluconate]] to reduce muscle spasm is an outdated therapy not favored by toxicologists<ref>Clark RF et al. Clinical presentation and treatment of black widow spider envenomation: a review of 163 cases. Ann Emerg Med. 1992 Jul;21(7):782-7.</ref>


==Disposition==
==Disposition==
*Generally may be discharged
*Consider admission for:  
*Consider admission for:  
**Symptoms of moderate envenomation  
**Symptoms of moderate or severe envenomation  
**Pregnant women  
**Pregnant women  
**Children  
**Children  
**Pts w/ preexisting cardiovascular disease or HTN
**Preexisting cardiovascular disease or hypertension


==See Also==
==See Also==
*[[Bites and Stings]]
*[[Envenomations, bites and stings]]


==External Links==
==External Links==


==References==
==References==
<references/>
<references/>


[[Category:Environ]]
[[Category:Environmental]]
[[Category:Derm]]
[[Category:Dermatology]]

Revision as of 17:23, 24 September 2019

Background

  • Identification: red hourglass on otherwise black spider
  • Genus: Latrodectus
Black widow spider

Mechanism

  • α-Latrotoxin envenomation causes massive release of neurotransmitters (norepinephrine, dopamine, acetylcholine, glutamate and GABA) from the nerve terminals → muscle cramps, tachycardia, hypertension
  • This clinical envenomation syndrome is known as latrodectism

Clinical Features

Local

  • Pinprick sensation; then increasing local pain that may spread to entire extremity
  • Erythema appears 20-60 min after the bite
  • Pain begins to abate after several hours and disappears by 2-3d

Systemic

Grading System

  • Grade 1: Range from no symptoms to local pain at the envenomation site with normal vital signs
  • Grade 2: Involve muscular pain at the envenomation site to migration to the trunk, diaphoresis at bite site and normal vital signs
  • Grade 3: Include grade 2 with abnormal vital signs; diaphoresis distant to envenomation site, generalized myalgia to back, chest and abdomen, nausea vomiting and headaches.

Differential Diagnosis

Envenomations, bites and stings

Evaluation

  • Generally clinical diagnosis

Management

  • Local wound care, analgesia and tetanus prophylaxis are mainstays of treatment
  • Antivenin - indicated for systemic illness only
    • Dosage: Usual dose is one to two vials diluted in 50 to 100 mL 5% dextrose or 0.9% sodium chloride, then infused over 1 hour
    • Use is controversial - Morbidity (pain, cramping and autonomic disturbances) are high, but mortality is low. Antivenin is horse serum derived, and can lead to anaphylaxis and serum sickness
    • Consider for: Pediatric patients, pregnant women, elderly

Not Indicated

  • Routine antibiotic use is not indicated
  • IV calcium gluconate to reduce muscle spasm is an outdated therapy not favored by toxicologists[1]

Disposition

  • Generally may be discharged
  • Consider admission for:
    • Symptoms of moderate or severe envenomation
    • Pregnant women
    • Children
    • Preexisting cardiovascular disease or hypertension

See Also

External Links

References

  1. Clark RF et al. Clinical presentation and treatment of black widow spider envenomation: a review of 163 cases. Ann Emerg Med. 1992 Jul;21(7):782-7.