Wilderness and Rescue Medicine 7th Edition Jeffrey Isaac, PA-C and David E. Johnson, MD

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Section V: Environmental Medicine

hydration and monitoring, with respiratory sup- port in severe cases. Symptoms developing after consumption of fish and shellfish should be treated like any other ingested toxin. Water and activated charcoal help dilute and remove the toxin, minimizing absorption by the gut. Hives and itching can be effectively treated with an antihistamine, such as diphenhydramine or ranitidine. Persistent, pro- gressive, or severe neurologic symptoms should be evacuated to medical care.

intact. Topical steroid creams may be helpful for superficial inflammation. Antibiotic ointment may help prevent infection. Remember that the toxin may still be present on clothing and equipment that could come in contact with the patient or other members of the group. Examples of toxins that continue to spread on fingers and clothing include poison ivy (an allergen) and manchineel sap. Clean your gear thoroughly with an oil-dissolving soap or solvent to avoid perpetuating the problem.

Surface Absorbed

General Principles

Ingested Toxins

General Principles

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24 Paralytic and Neurotoxic Shellfish Poisoning: • Neurotoxin produced by algae concentrated in filter feeding shellfish (eg Red Tide) • Not destroyed by cooking • Symptoms include vomiting, diarrhea, neurologic symptoms, seizure, respiratory distress. • Generic treatment is symptomatic, including

Eg: Manchineeal sap, organophosphate fertilizers. Treatment: • BLS, PROP • Remove and dilute: brush off or irrigate with water. • Dress open wounds, burns, and blisters. BSA >10% is high risk. • Evacuate with ALS assistance as needed. • Contact poison control.

volume replacement and antiemetics. • Evacuate to medical care if possible.

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©2018WMA

©2018WMA

High-Risk Topical Exposure As with large burns or abrasions, the surface area involved in topical toxin exposure can lead to serious problems with even superficial injury. Anticipated problems in large surface area inflam- mation include dehydration, infection, and hypo- thermia. Any inflammatory process occupying more than about 10% of the body’s surface area should be considered high risk. Be alert to respi- ratory involvement that carries the anticipated problem of respiratory distress and failure. Inhaled Toxins Toxic inhalation can cause problems through two distinct mechanisms. Inhaled substances can either be absorbed through the respiratory system into the systemic circulation or cause direct respi- ratory system injury. Carbon monoxide poison- ing from using a heater or stove inside a poorly vented snow cave is an example of the former, and chlorine gas is an example of the latter.

Topical Toxins Topical exposure can inflame the skin surface at the site of contact, causing open wounds at risk for infection. Toxins can also be absorbed through the skin, causing systemic effects. In the back- country, most topical toxins come from plants like daphne and poison ivy that cause localized allergic reactions and inflammation. A few ani- mals like the buffo toad excrete a toxin that causes primarily local effects on the skin of humans but can severely injure dogs and predators. For treatment, clean the exposed area as you would for any skin wound. Irrigate copiously with water. Removal of some substances, such as manchineel sap (Hippomane mancinella) may require a different solvent capable of dissolv- ing waxy or oily compounds. Alcohol, vinegar, and even WD-40 have found a place in initial treatment. Check with local medical facilities for recommendation on treating exposure to poisonous plants, preferably before the exposure occurs. Blisters caused by toxins should be left