A 52-year-old male was found by his daughter in a bathroom at his home after becoming very dizzy and nauseated. He thought that he might vomit and had been in the bathroom for more than an hour trying to throw up. He had no other symptoms except for a sense of tingling in his fingers.
The patient admitted that he had been trying to kill a bees' nest in the yard by spraying chemicals on it for the past few days. He had sprayed two cans of insecticide a "few days ago" and about half of a can shortly before 9-1-1 was called.
Upon arrival, the EMS crew noted an alert male in some distress. The patient's Glasgow Coma Scale was estimated to be 15. The pulse rate was 62 beats per minute. The patient's blood pressure was 90/68 mmHg. The respiratory rate was 38 breaths per minute. The skin was flushed, warm and very diaphoretic (sweaty). However, the remainder of a detailed physical assessment was unremarkable, including the breath sounds and pupils.
An initial oxygen saturation was not reported. However, two saturation assessments after placement of a nasal cannula at six liters per minute were 98% and 99% respectively. No end-tidal carbon dioxide evaluation was made. The blood glucose was 138 milligrams (mg) per deciliter.
An intravenous (IV) line was established and the patient received 1,200 milliliters of fluid enroute to the hospital. Oxygen was applied as noted above. The respiratory rate continued over 30 breaths per minute, but the blood pressure improved to 110/70 mmHg. The patient received 12.5 mg of promethazine (phenergan) IV for nausea enroute. Additionally, 25 mg of diphenhydramine (Bendadryl) was administered for "phenothiazine reaction" prevention.
The ambulance arrived at the destination hospital without incident, and the patient's condition did not deteriorate. One can of the agent used by the patient was brought to the facility for staff evaluation.
Shortly after arrival, involved EMS agencies were made aware of a complaint from the receiving hospital regarding the prehospital care of this patient.
Questions to Consider
What do you think the most likely explanation for the patient's symptoms is?
What other less likely possibilities might account for his presentation?
Based on your responses to the first two questions, do you think the management of this case in the field was appropriate?
What do you think the hospital's complaint might be?
The patient recovered without complication. He remained in the emergency department and was treated symptomatically. He underwent a procedure before being admitted to a medical floor for a period of overnight observation and was later discharged.
Most EMS professionals would likely conclude that the patient's symptoms were related to the chemical he had been using liberally to attack the bee hive in his yard. However, we should always consider less likely possible explanations. Alternative conditions to ponder include inner ear disturbances resulting in nausea and dizziness, certain types of strokes, hypoglycemia, viral infections, prescription drug effect and atypical cardiac disease.
In this case, the chemical being used was felt to fully explain the patient's symptoms. Many providers may be familiar with a class of insecticides known as organophosphates. These agents are related to some of the deadly nerve agents that have been used by some despotic leaders and feared as potential chemical terror threats for the future. In sufficient quantity, these agents, including organophosphates, kill by ultimately producing respiratory failure.
Some of this patient's signs and symptoms were suggestive of organophosphate exposure, but others were not. Organophosphates typically produce a "cholinergic syndrome" because of irreversible binding to cholinesterase receptors at nerve endings. The result is an accumulation of the neuro transmitter acetylcholine at nerve synapses. This causes over stimulation and disruption of nerve transmission.
Signs of cholinergic syndrome include bradycardia, salivation, vomiting, diarrhea and sweating. Additionally, weakness, tremors (muscle fasciculations), seizures and parathesias (tingling) may be noted. The pupils are usually small, almost pin point a term known as miosis.
Some patients may experience respiratory distress due to the development of pulmonary edema in response to organophosphates.
Patients may be exposed to organophosphates via oral, skin, gastrointestinal, eye and respiratory routes. During my residency, we saw a disproportionate number of severe examples of these cases, and the vast majority was non-intentional oral ingestions. ("Somebody filled up a soda bottle with a pesticide and placed it in the refrigerator, and I accidentally drank it," was a very common refrain).
Initial treatment for organophosphates involves high, and typically repeated, doses of atropine to counteract the cholinergic syndrome.
The patient in this case had some suggestion of organophosphate symptoms. These included the sweating, or diaphoresis, the rapid respiratory rate and the parasthesias. However, he was not reported to be salivating, vomiting or to have diarrhea. He was also not significantly bradycardic. No rales were heard on auscultation of the lungs. Perhaps most obviously, the pupils were normal.
Examination of the can the patient was using to spray the beehive revealed the contents to contain pyrethroid. Pyrethroids are a synthetic chemical class derived from pyrethrins. Pyrethrins themselves are substances known as esters and are obtained from chrysanthemum flowers. They have been used as insecticides in China since the 1st century AD.
Estimates place the presence of pyrethroids in more than 2,000 commercial insecticide products currently available. Pyrethroids are frequently used as the active agents in community mosquito spraying operations. However, there have been reports of increasing resistance to the effects of pyrethroids by target insects.
Pyrethroids kill insects by nervous system paralysis, as a result of interference with sodium movement in the nerve cells. Humans, and other mammals, are relatively unaffected by pyrethroids when used in normal quantities. Patient exposure routes are the same as outlined above for organophosphates.
There are two general categories of pyrethroids: Type I and Type II. Type II is generally believed to be more toxic than Type I. Symptoms of exposure to this chemical include tremors, twitching, parasthesias and nausea. Type II symptoms may be more severe and can be difficult to distinguish from organophosphate toxicity at high levels.
Treatment for either Type I or Type II exposures is symptomatic. Atropine does not provide any benefit, and there are no specific antidotes. The main emphasis should be skin decontamination, since this is the most likely route of exposure in the vast majority of cases. Activated charcoal may have some role if a gastrointestinal ingestion is known to have occurred.
This patient very likely had a significant potential skin and respiratory exposure to a pyrethroid agent. Strong consideration to field decontamination should have been given to reduce the continued exposure to the chemical by caregivers. This did not occur and was not really considered.
The hospital's concern focused on the specific issue of failure to decontaminate prior to arrival. Some providers in the hospital complained of nausea and dizziness after brief contact with the patient. The patient was then transported to the decontamination shower. The patient's symptoms rapidly resolved, and there were no further physical effects noted by providers.
What Can We in EMS Learn from this Case?
- Consider the possibility of chemical/biologic exposure (see the Conclusion for more on this point);
- Use appropriate personal protective equipment with cases possibly representing a chemical or biological exposure. This, of course, hinges on the recognition of a possible exposure;
- Protect EMS crews and others on the scene or at hospitals from exposure to the agent. We have not helped ourselves, the patient, or future patients if critical personnel inadvertently become sickened from an incorrectly managed toxic hazard;
- Prompt decontamination is the mainstay in the initial management in suspected chemical exposures;
- As in any case, manage the ABC's but only after the patient has been properly decontaminated to avoid injury to providers; and
- Realize that most exposures have no specific antidotes and be prepared to treat symptomatically.
While this case is a small example, the failure to recognize and properly treat a chemical exposure furthers my personal bias that we are not really prepared to recognize or deal with mass chemical or biologic exposures.
My longstanding concern is based on the following points:
We do not often encounter patients with Hazmat exposures. Therefore, we commonly forget about the possibility. We are all subject to complacency. Since the frequency of significant chemical or biologic exposure cases is miniscule, it's very easy to overlook.
Despite all the talk about preparation and the numerous training opportunities that have occurred since 9/11, I have this nagging sense that there is a lack of real direction regionally and nationally in the management of any disaster circumstance. We have already seen examples of this in the recent past. It is my perception that the multiple entities involved in such a crisis will likely be working at cross purposes and be unable to adequately communicate with each other. In effect, the right hand will not know what the left hand is doing, and the result will be casualties that might have been preventable. The concept of coordination (or "interoperability") seems lacking to me.
Many EMS agencies and hospitals have obtained financial grants from the Department of Homeland Security ostensibly to assist in the readiness for a possible mass casualty exposure. We have been more than happy to take this money in the name of disaster preparedness. Yet, much of the equipment purchased with these funds is in daily use for routine patient care having nothing to do with biologic or chemical exposure cases.
So, we are willing to accept money for patient care products we could not otherwise obtain and we are more than willing to use these items in the everyday care of non-exposure cases. A cynic might view this as a financial boondoggle.
But, in return, are we really doing our share to be prepared for the unthinkable? Are we working with local, regional, state and federal agencies to be ready? Do we have plans in place in response to disasters be they biologic, chemical and others? Do we practice those plans frequently? Are we actively training our crews on recognition and management of biologic and chemical exposures knowing they are seeing very few actual cases? Are we stressing liberal use of personal protective equipment, consideration of early decontamination and other basic Hazmat management principles?
Problem is ... in many situations the issues are not seriously addressed until the next mass casualty crisis refocuses attention temporarily.