Setting: ED
CC: “There was a spider in my shoe, and I stepped on it.”
VS: normal
HPI: A 62-year-old man was getting up in the morning in his beach house on the Jersey shore when he put his foot into a shoe and experienced a sudden sharp pain. He originally thought that he stepped on a nail or piece of glass. He found a dead spider in the shoe. Over the next few hours, he developed waves of abdominal pain so severe he came to the ED.
PMHx/Medications: none
PE:
General: very uncomfortable; clearly in pain
Chest: clear
Abdomen: rigid, not tender; no rebound.
Cardiovascular: normal
Initial Orders:
Antivenin
CHEM-7
Calcium level
Upright chest x-ray
Abdominal x-ray
Brown Recluse Spider Bite
• Local necrosis of skin
• No specific test
• Wound debridement
• Dapsone or steroids (sometimes help)
Black Widow Spider Bite
• Red hourglass on belly of spider
• Calcium chelation
• Abdominal pain
As you move the clock forward, consult poison control or toxicology on spider, snake, and insect bites.
If you remember a test or treatment you forgot to order before you move the clock forward, just order it and you will lose no points at all. The “penalty” on your score for forgetting to order a test or treatment is based on how long you move the clock forward before ordering it.
Reports:
CHEM-7: normal
Calcium level: 6.4 mg/dL (low)
Upright chest x-ray: normal; no air under diaphragm
Abdominal x-ray: normal; no ileus, no air or fluid levels
Perforation of GI Organs and Intestines
• Free air is detected on chest x-ray.
• Chest x-rays always show the top of the diaphragm.
Abdominal X-ray
• Only for ileus or small bowel obstruction
Orders:
IV calcium
Antivenom if not already ordered
Transfer patient to ICU
Use ICU observation in black widow spider bites (Figure 11-3). Observe for:
• Seizures
• Prolonged QT on ECG
• Worsening tetany
• Laryngospasm
Figure 11-3. Black widow spider (with offspring). Latrodectus mactans, with characteristic hourglass marking on its abdomen. (Photograph by Lawrence B. Stack, MD, reproduced with permission from Knoop KJ, et al. The Atlas of Emergency Medicine, 3rd ed. New York: McGraw-Hill; 2010.)
Low Calcium Level = Abnormal Excess Muscle and Neural Depolarization
Move the clock forward, do an Interval History, and reexamine the abdomen.
Interval History: “Patient still in severe abdominal pain.”
Abdomen: rigid, tight, not tender; no change
Black widow spider venom chelates calcium.
Low calcium level causes tetany.
Low serum calcium level decreases the threshold for depolarization.
After giving the calcium, the abdominal pain starts to improve. Antivenin has been administered. When the calcium level normalizes and abdominal pain has resolved, the patient can be transferred back to the hospital floor.