TY - CHAP M1 - Book, Section TI - Black Widow Spider Envenomation A1 - Zafren, Ken A1 - Thurman, R. Jason A1 - Jones, Ian D. A2 - Knoop, Kevin J. A2 - Stack, Lawrence B. A2 - Storrow, Alan B. A2 - Thurman, R. Jason PY - 2021 T2 - The Atlas of Emergency Medicine, 5e AB - The black widow spider (Latrodectus mactans) is the prototype for the genus Latrodectus, several members of which cause human disease. The black widow spider is not particularly aggressive but will defend her web, which is often found in woodpiles, basements, and garages. Most envenomations occur between April and October, with bites most commonly located on the hand and forearm. The clinical presentation of severe and sustained muscle spasm is produced by a neurotoxic protein, which causes the release of acetylcholine and norepinephrine at the presynaptic neuromuscular junction. The initial bite may be mild to moderately painful but is often missed. Within approximately 1 hour, local erythema and muscle cramping begin, followed by generalized cramping involving large muscle groups such as the thighs, shoulders, abdomen, and back. Associated clinical features can include fasciculations, weakness, fever, salivation, vomiting, diaphoresis, localized sweating at the envenomation site, and a characteristic pattern of facial swelling called Latrodectus facies. Rare cases of seizures, uncontrolled hypertension, and respiratory arrest have occurred. SN - PB - McGraw-Hill CY - New York, NY Y2 - 2024/03/29 UR - accessmedicine.mhmedical.com/content.aspx?aid=1181050952 ER -