UMEM Educational Pearls

Category: Toxicology

Title: Black Widow Bite

Keywords: Lactrodectus (PubMed Search)

Posted: 6/29/2017 by Kathy Prybys, DO (Emailed: 6/30/2017) (Updated: 6/30/2017)
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 Black widow  spiders belong to the genus Latro dectus which include 31 species of widow spiders found throughout world. Approximately 1500-2500 black widow bites are reported to American poison control centers annually. A black widow can be identified by their hourglass pattern (red or orange) on the ventral aspect of their shiny globular abdomen. Fortunately, envenomation is rare but when it does occur it causes severe pain, muscle cramping, abdominal (may mimic acute abdomen) often refractory to traditional analgesics and antivenom (Antivenin Latrodectus mactans) is available and effective . Alpha-latrotoxin is the potent toxin causing presynaptic cation channels to open (calcium) and release of neurotransmitters such acetycholine. The neurological signs and symptoms caused by predominantly autonomic and include tachycardia and hypertension. The antivenom is equine based and infused over 20-30 minutes with pain relief in 20 minutes.



Neurotoxic manifestations of black widow spider envenomation in pediatric patients. Sotelo-Cruz N, Gómez-Rivera N. Neurologia. 2016 May;31(4):215-22.


The Black Widow spider bite: differential, clinical manifestations, and treatment options. Shackleford R, Veillon D, Maxwell N, LaChance L, Jusino T, Cotelingam J, Carrington P. J La State Med Soc. 2015 Mar-Apr;167(2):74-8.




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