Sweating, Pinpoint Pupils, and 'It's Just the Heat'
At 4:30 p.m. on a 96 F day, a 34-year-old farmworker who spent the morning loading and mixing an organophosphate insecticide tells you he feels 'off.' He reports headache, nausea, sweating, blurred vision, and a runny nose with excess salivation. The label carries a Danger/Poison signal word and states that repeated exposures may cause cholinesterase inhibition. His coveralls are damp, the left glove has a tear, and his forearms are wet from handling the tank. He is sitting on the tailgate and refuses an ambulance because 'it's just the heat.' A second crew member is standing nearby drinking water.
1. Which findings argue against heat exhaustion alone, and what is the most likely explanation?
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Heat alone does not explain this picture. Findings that point away from heat exhaustion:
- Pinpoint pupils (miosis) - heat illness does not constrict pupils.
- Excess salivation, runny nose, and tearing - heat causes sweating, not secretory excess from the eyes, nose, and mouth.
- Muscle twitching or fasciculations if present - heat cramps are painful muscle contraction, not fine twitching.
- Blurred vision and the wet forearms with a torn glove - a dermal route of exposure that matches the timeline (morning mixing, symptoms late afternoon).
- Slow pulse - heat exhaustion typically produces a rapid, weak pulse.
Sweating, nausea, headache, and weakness overlap with heat illness, which is exactly what makes this dangerous: the shared symptoms let the worker - and a hurried supervisor - write it off as heat. The combination of secretory excess (salivation, lacrimation, rhinorrhea), miosis, and a documented organophosphate mixing exposure is the classic cholinergic toxidrome from cholinesterase inhibition. Treat it as a poisoning until a physician says otherwise.
2. Lay out your immediate actions, including what you send with EMS and what you must NOT do.
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Immediate actions:
- Call 911 now. Do not negotiate with the worker about the ambulance. Tell the dispatcher it is a suspected organophosphate poisoning with dermal exposure.
- Decontaminate before transport - remove contaminated coveralls, boots, and the torn glove, double-bag them, and wash the skin thoroughly with soap and water. Protect yourself with chemical-resistant gloves while doing this; you can become the next victim. Irrigate eyes with clean water if there is any chance of splash.
- Move him to shade, keep him still, and monitor breathing. If breathing stops, start rescue breathing - mouth-to-mouth is generally avoided with a contaminated victim; use a barrier device.
- Nothing by mouth. Do not induce vomiting, do not give water, milk, or any home remedy. Do not give atropine - atropine is a physician-administered antidote and the dose decision requires medical assessment.
- Send with EMS: the product label and SDS, the EPA registration number, the product name, the estimated exposure time and route, the time symptoms began, and a written note that a cholinesterase test may be indicated. Also give the names of the products handled that morning - a second crew member should ride or follow, since the worker should not be alone or driving.
Follow-up the same day: stop the mixing operation, review why a torn glove and wet forearms went unnoticed, and check whether the other mixer has symptoms.