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Latrodectus spp.

Latrodectus spp.: describe their general characteristics, habitats, pathophysiology, symptoms, and treatment modalities.

  • *Lactrodectus mactans and geometricus are the black widow and brown widow, respectively.
  • *Widows are found all over the United States (except Alaska), but seem to be more predominant in the south. The are also found abundantly across the globe in non-arctic regions.
  • *Envenomation from the bite infiltrates a variety of insect/crustacean specific toxins and alpha-latrotoxin, which is a pore forming toxin at the presynaptic terminal. Ca2+ influxes as a result, leading to an exocytosis of neurotransmitters (eg, NE, dopamine, seratonin, GABA, glutamine, etc).
  • *Pain can be local, regional, or systemic. Systemic manifestations involved generalized myalgia, headache, diaphoresis, and abnormal vital signs. Myopathy can also occur, which may progress to rhabdomyolysis and acute renal failure.
  • *Indications for antivenom include high risk populations with severe symptoms, such as pregnant patients.
  • *Treatment should predominantly involve benzodiazepines and opioid analgesics for moderate to severe symptoms. Minor symptoms can be treated with NSAIDs and cold packs.
  • ***Bonus: females practice sexual cannibalism and eat the males after copulation.

L. Geometricus 

Mfield, Matthew Field, http://www.photography.mattfield.com [GFDL 1.2 (http://www.gnu.org/licenses/old-licenses/fdl-1.2.html)]

L. Mactans

Shenrich91 [CC BY-SA 3.0 (https://creativecommons.org/licenses/by-sa/3.0)]