Wilderness and Rescue Medicine 8th Edition

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Section V: Environmental Medicine

spasm, and cramping. An exposure occupying more than 50% of a limb should be considered potentially serious with anticipated systemic neu- rotoxic effects. Truly life-threatening symptoms are generally limited to Portuguese man-of-war and the Indo-Pacific box jellyfish stings. Medical follow-up is recommended for any exposure that produces significant systemic symptoms. The box jellyfish venom can produce cardiac arrhythmia, respiratory paralysis, and a danger- ous elevation of blood pressure. For this reason, antivenom to this toxin is carried and adminis- tered in the field by rescue personnel in high- incidence areas of Australia and Southeast Asia. BLS and immediate evacuation are indicated. Consult local authorities about the area where you plan to operate. There is no antivenom for the Portuguese man- of-war. Fortunately, fatalities from exposure are very rare. Symptoms include severe burning sen- sations and skin redness that tend to disappear within an hour. Initial treatment includes only flushing with water, removal of tentacles, and treatment for pain. In the case of Portuguese man-of-war stings, vinegar is not recommended. More significant exposure can cause muscle cramping, temporary numbness and weakness in the area, and lymph node swelling. Allergic reac- tions are uncommon, but the practitioner should be alert to the signs and symptoms of anaphylaxis mixed with the toxic effects. Any persistent or severe symptoms require follow-up medical care. Insects and Arachnids Insect and arachnid venom are injected by a stinger or specialized mouthparts as the animal attempts to defend itself or warn you away from a nest. It is meant to hurt, and it usually does. This is typical of wasps, fire ants, spiders, and scor- pions. More commonly, your skin reacts to the irritation of substances used by a feeding insect to prevent clotting of your blood. Many of them also inject a local anesthetic to reduce the pain caused by the bite, at least for as long as they’re feeding. Examples of these insects include black flies, deer flies, moose flies, mosquitoes, and no-see-ums.

Local reaction to toxins can be severe but involve only the extremity or immediate area of the bite or sting. There may be some degree of acute stress reaction (ASR) that must be distinguished from systemic effects. Local reactions are treated for comfort. Use cool soaks, elevation, and rest. Aspirin, ibuprofen, or other anti-inflammatory pain medications help, as do diphenhydramine or other antihistamines. The effects of a large toxin load can be immediate (as with a large number of bee stings) or delayed up to 24 hours. Delayed reactions are common in black fly country in the spring and early summer. Symptoms include fever, fatigue, headache, and nausea. This is not an allergic reaction if the gen- eralized swelling, respiratory distress, and other signs of anaphylaxis are absent. Toxin load does not usually cause a serious critical system problem. Observe the patient for 24 hours. Give aspirin, ibuprofen, or other anti- inflammatory pain reliever for comfort. Watch for signs of infection at the site of insect bites. Keep the patient well hydrated and protected from excessive cooling or heating. Black Widow The black widow spider (Latrodectus mactans), found in the warmer parts of the United States and further south, uses a potent neurotoxin to immobilize prey and as a defense mechanism.This spider prefers dark and quiet places to feed and nest. People are bitten most often when reaching into confined spaces or sitting on an outhouse seat. The bite itself is mildly uncomfortable or painless.

Black widow (Latrodectus mactans)