A 33-year-old patient presents with severe abdominal pain and a rigid abdomen after a bite on the back of the hand. Which envenomation is most likely?

• A. Black widow spider bite
• B. Scorpion sting
• C. Brown recluse bite
• D. Bee sting

Answer: (A)

The main idea is recognizing a toxin that causes painful, sustained muscle contractions, especially in the abdominal wall. Black widow venom contains latrotoxin, which provokes a massive release of neurotransmitters at nerve endings, leading to severe muscle cramping and rigidity. When this toxin affects the abdominal muscles, it can produce a rigid, severely painful abdomen after a bite on the hand. The other envenomations have different patterns: brown recluse bites typically cause local tissue necrosis with little systemic muscle cramping; scorpion stings can cause pain and autonomic symptoms but abdominal rigidity is not as characteristic; bee stings mostly cause local pain and swelling and can trigger anaphylaxis rather than sustained abdominal muscle rigidity. So this presentation best fits a black widow spider bite.