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

Chapter 23: Toxins, Envenomation, and Disease Vectors

Toxic substances can produce systemic effects, local effects, or both. Toxins, like trauma, can cause simultaneous involvement of more than one body system. The cause-and-effect relation- ship may be fairly obvious or quite confusing. Fortunately for field medicine, generic diagnoses and general principles work well. A toxin can also be an allergen causing a release of histamine in addition to its toxic effects. A hor- net sting producing anaphylaxis is an example of a substance that can do both. Fortunately, a toxic reaction is not often mixed with allergy, even though the type of exposure and symptoms may be similar. Systemic toxins are those that affect the body as a whole. They may be ingested, injected, inhaled, or absorbed through the skin. Some common examples include mushrooms, organophosphate pesticides, and carbon monoxide. These toxins can represent an immediate threat to the function of the critical body systems. Local toxins affect only the immediate area of contact. The toxin in a tarantula bite does not significantly affect critical body systems but may cause localized tissue swelling and pain. Some toxins have both systemic and local effects. An example would be an inhaled gas that irritates the respiratory systemwhile being absorbed into the general circulation.

When you are not sure exactly what you are dealing with, base your initial treatment on the presenting signs and symptoms and the environ- mental conditions. In short, the generic response is to treat what you see. Any toxin causing shock, respiratory distress, or brain failure represents an emergency in which urgent evacuation is indicated. Although you should try to obtain as much information from the scene as possible, the investigation should not delay appropriate evacuation and life support or increase the danger to rescuers. Generic Treatment for Toxin Exposure: • Support critical body systems. • Treat what you see.

• Treat anaphylaxis if you see it. • Maintain body core temperature

• Maintain hydration. • Provide pain relief.

• Remove or dilute the toxin, if possible. • Evacuate (ALS intercept as needed). • Provide antidote if available.