Articles: spider-bites.
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Spiders are a source of intrigue and fear, and several myths exist about their medical effects. Many people believe that bites from various spider species cause necrotic ulceration, despite evidence that most suspected cases of necrotic arachnidism are caused by something other than a spider bite. Latrodectism and loxoscelism are the most important clinical syndromes resulting from spider bite. ⋯ Systemic loxoscelism is characterised by intravascular haemolysis and renal failure on occasion. Other important spiders include the Australian funnel-web spider (Atrax spp and Hadronyche spp) and the armed spider (Phoneutria spp) from Brazil. Antivenoms are an important treatment for spider envenomation but have been less successful than have those for snake envenomation, with concerns about their effectiveness for both latrodectism and loxoscelism.
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Black widow spider (Latrodectus spp.) envenomation remains the most clinically significant spider envenomation in the US. The syndrome is characterized by painful muscle rigidity and autonomic disturbances. Treatment has ranged from symptomatic care to administration of specific antivenom. Declining antivenom availability and, possibly, the fear of hypersensitivity allergic reactions, has limited antivenom use in the US. ⋯ In the US, most symptomatic Latrodectus spp. exposures reported to the NPDS are minor. Few patients receive antivenom, although antivenom is associated with shorter symptom duration among moderate and major outcomes.
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Review Case Reports
Necrotic arachnidism and intractable pain from recluse spider bites treated with lumbar sympathetic block: a case report and review of literature.
Brown recluse (Loxosceles reclusa) spider bites mainly occur in the southern and Midwestern United States. The clinical manifestation of brown recluse spider bites varies from skin irritation, a small area of tissue damage to neuropathic pain, necrotic arachnidism and severe systemic reactions such as acute renal failure and even death. Treatment is controversial and nonspecific. ⋯ Both his pain and tissue necrosis improved significantly with lumbar sympathetic block with local anesthetic. After a series of lumbar sympathetic blocks, his symptoms resolved and lower extremity wound healed rapidly. We discuss the benefit of sympathetic blockade not only for neuropathic pain but also possibly as a treatment for necrotic arachnidism from a brown recluse spider bite.
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The European spider Tegenaria agrestis (Walckenaer) (hobo spider) has been implicated as a spider of medical importance in the Pacific Northwest since its introduction in the late 1980s. Studies have indicated that the hobo spider causes necrotic tissue lesions through hemolytic venom or through the transfer of pathogenic bacteria introduced by its bite. Bacterial infections are often diagnosed as spider bites, in particular the pathogenic bacteria methicillin-resistant Staphylococcus aureus (MRSA). ⋯ We found 10 genera of ubiquitous bacteria on the exterior surface of the spiders. In addition, none of the spiders exposed to MRSA transferred this pathogen. Finally, the hemolytic venom assay corroborates previous studies that found hobo spider venom was not deleterious to vertebrate red blood cells.