From manure pit accidents to cannabis laced with rodenticide, rural hospitals see a wide variety of toxicologyemergencies. In these situations, the ideal diagnostics often aren’t available, and treatments can be in short supply. These challenges make quick thinking and creative supply solutions essential, presenters noted at the ASHP Midyear 2025 Clinical Meeting & Exposition, in Las Vegas.
Rural medicine providers serve 97% of the U.S. landmass and the 1 in 5 Americans who live there (U.S. Census Bureau; 2016). The remote locations and limited resources often available to these communities can make all forms of healthcare challenging and toxicology emergencies particularly dangerous, according to the speakers. They provided an overview of common inhaled, ingested, and chemical burn emergencies that rural pharmacists face, along with treatment approaches tailored to the rural hospital setting.
Ingested Toxins
Long-acting anticoagulant rodenticides (LAARs) are available in every hardware store and garden shop, said Kyler Crouse, PharmD, a clinical pharmacist at Aurora BayCare Medical Center, in Wisconsin. Also known as superwarfarins, these rodenticides interfere with blood clotting by the same mechanism as warfarin, but—due to much longer molecular side chains—their activity lasts much longer.
Accidental exposures to LAARs are most common and typically asymptomatic, Dr. Crouse said. Intentional exposure to LAARs is typically much more severe.
Although most exposure comes directly from handling the rodenticide product, some cases have been linked to unintentional exposure through recreational drug use, such as an outbreak in Wisconsin between 2000 and the early 2010s where synthetic cannabinoids were laced with LAARs to potentiate the high.
In the clinic, LAAR ingestion closely follows traditional warfarin toxicity or vitamin K antagonist toxicity, Dr. Crouse said. The toxin rapidly distributes into the tissues and liver, causing moderate to life-threatening bleeding. And because of the long half-life (16-62 days) of these pesticides, it can take six months to a year to see symptoms fully resolve.
If the patient has confirmed bleeding, the case should be treated like a hemorrhagic emergency. For patients who are asymptomatic, rural hospitals rarely have access to serum drug level testing onsite. Accordingly, Dr. Crouse cited guidelines for vitamin K toxicity: an international normalized ratio to measure clotting time, and a follow-up 48 hours later to rule out delayed onset (Goldfrank’s Toxicologic Emergencies, 11th ed. 2019). For unintentional, asymptomatic exposures, providers should opt for activated charcoal if ingestion occurred within the prior two hours. But if the patient is symptomatic, ingested 1 mg of LAAR or more, or the exposure is intentional, then treatment is consistent with vitamin K toxicity: gastrointestinal decontamination, four-factor prothrombin complex concentrate administration, and vitamin K supplementation.
The one major difference for LAAR toxicity is that the required doses of vitamin K are significantly higher, with loading doses as high as 400 mg recommended (Recognition and Management of Pesticide Poisonings, 6th ed. Environmental Protection Agency; 2013:165-179). These cases call for “massively huge doses compared to what we would see for any warfarin toxicity,” Dr. Crouse said. And that loading dose is followed by a maintenance dose of 7 mg/kg vitamin K per 24 hours, divided into four doses given every six hours.
It may take up to 180 days of therapy to treat LAAR toxicity, which adds up to a lot of vitamin K, Dr. Crouse said. In a rural setting, many facilities won’t have enough on hand to supply such a patient for even a week. “We would have to start reaching out to other facilities in our network to be able to allocate [enough treatment],” he said. “So, in these settings, make sure you’re considering what drug supply you actually have.”
Inhaled Toxins
Jennifer A. Esch, PharmD, MBA, opened her presentation on inhaled toxins with a devastating scenario: a toxicology emergency turned mass casualty in Menominee, Michigan. In 1989, a worker injured his head while trying to repair the manure pit on his family’s dairy farm, and four different family members rushed to try to save him. All five lost their lives.
The culprit was hydrogen sulfide poisoning. Hydrogen sulfide is a chemical asphyxiant—like carbon monoxide or cyanide—that collects in the enclosed manure pits of large dairy and beef operations, said Dr. Esch, a clinical pharmacist specialist at Advocate Health, in Wisconsin. With decomposition, the manure emits a gas heavier than air, causing it to accumulate above the tank. And the anaerobic conditions of the tanks can convert sulfur (from water or animal bedding) into hydrogen sulfide.
Hydrogen sulfide forms gas pockets in the manure tank that are released when the tank is agitated or cleaned. This makes emptying, filling, and stirring the tank, or any ventilation malfunction, very risky.
Hydrogen sulfide “reacts with moisture on the surface of mucous membranes to produce intense irritation and corrosive injuries,” Dr. Esch said. “Eyes, nasal, and respiratory mucous membranes are the tissues most susceptible to direct injury.” The gas can also create a stunning effect, rendering a person unconscious in just one or two breaths.
A 2007 study looking at manure-handling-related deaths found that 34% of fatalities occurred during tank repairs; another 22% involved family or co-workers attempting to rescue the initial victim (J Agromedicine 2007;12:3-23).
The care team can deduce exposure to hydrogen sulfide based on context, such as reports of a stunning effect or working on a dairy farm around a manure pit. Once these patients have reached the emergency department (ED), maximizing oxygenation is the priority, Dr. Esch said. 100% oxygen should be administered, bicarbonate if needed to neutralize excess acid, and crystalloids and vasopressors for hypotension.
The antidote is sodium nitrite. “Nitrite-generated methemoglobin acts as a scavenger of the sulfide,” Dr. Esch said. Administer as a 3% solution via IV push over three to four minutes. Patients should be watched for hypotension, and methemoglobin levels should be measured after 30 minutes.
Chemical Burns
Most chemical burn cases in rural communities occur when people encounter corrosive acids and bases on the job, said Autumn Peck, PharmD, MBA, an acute care clinical pharmacist at Geisinger Lewistown Hospital, in Pennsylvania.
Caustic acids
Among the caustic acid injuries seen in a rural ED are those caused by hydrofluoric acid, which is used in oil refineries and found in rust removers, stainless steel cleaners, and stone or brick cleaners. Upon contact with skin, hydrofluoric acid rapidly dissociates into hydrogen ions and fluoride anions that disrupt cellular membranes and spontaneously depolarize nerve tissues, causing severe pain.
“That fluoride ion will remain active until we deactivate it [with water irrigation],” Dr. Peck said.
Depending on the concentration of the hydrofluoric acid exposure, symptoms can range from blistering redness and pain to tetany and even cardiovascular issues such as arrhythmia and decreased myocardial contractility. If the solution was more dilute, the symptoms may not show up for eight to 24 hours. Patients may not even be aware they were exposed.
To gauge the severity of a patient’s chemical burn, rural clinicians can monitor serum electrolytes every four to six hours. They can also perform EKGs looking for QT prolongation caused by hypocalcemia from fluoride- binding calcium or peaked T waves caused by the fluoride binding to potassium, Dr. Peck said.
Treatment starts with copious water irrigation for 15 to 30 minutes. For some patients, this is enough. But if pain continues, the remaining fluoride ions need to be neutralized by replacing the magnesium and calcium cations. For mild to moderate burns, a topical 2.5% calcium gluconate gel can be applied to small burn areas or a 10% calcium gluconate intradermal or subcutaneous injection administered around the burn site.
In her own practice, Dr. Peck has found herself without either treatment option during a chemical burn emergency. But a topical solution can be made by combining 5 ounces of water-soluble lubricant with any of the following:
- 3.5 g of calcium gluconate powder;
- 25 mL of 10% calcium gluconate; or
- 10 g of crushed calcium carbonate (Tums, Haleon).
If the case is severe, and the patient also shows abnormalities in their lab values or EKGs, the patient needs immediate IV replacement of calcium, potassium, and magnesium. Lead with a calcium gluconate IV push or a calcium gluconate IV piggyback over four hours, Dr. Peck advised, and a 4-g IV magnesium sulfate piggyback. Administer potassium replacement as needed to stay above 3.5 mEq/L. Once treatment is started, the care team should schedule a telehealth consult with a burn unit.
Caustic bases
“This might be a surprise to some, but a caustic base is often considered more dangerous than a caustic acid because they can cause severe, long-lasting tissue damage,” Dr. Peck said.
Caustic or corrosive bases do their damage by producing a hydroxide ion that reacts with lipids in the skin. This liquid saponification disrupts the skin barrier, allowing the base to penetrate deeper. It can even result in liquefactive necrosis—“the literal liquefaction of the skin,” Dr. Peck said. “Essentially, the hydroxide is clearing the way for the base to go further down into the skin.”
In rural communities, anhydrous ammonia used to fertilize crop fields is a corrosive base that can land patients in the emergency room. It’s very water-soluble and kept in pressurized tanks at –28°F, so exposure can coincide with frostbite. Unfortunately, there is no antidote for dermal exposure. Immediate high-volume irrigation of the contact site is prescribed. That should be repeated every 4 to 6 hours for at least 24 hours while simultaneously controlling other symptoms like treating frostbite, wound care, and keeping airways open.
For ocular exposure, which can result in anterior ocular damage in under a minute, contacts should be removed immediately, and eyes should be flushed for 15 minutes and irrigated for two to three hours while monitoring eye pH. Use proparacaine hydrochloride 0.5% ophthalmic solution for analgesia and arithromycin as an antibiotic, consulting ophthalmology by telehealth as soon as possible.
Although the capacities for diagnostics and treatments may be different in rural hospitals, patient outcomes in toxicology can still be improved. It may just take an extra dose of creativity. “[In] rural medicine, we have to use what’s near us,” Dr. Peck said.
Original article online at: https://www.pharmacypracticenews.com/Clinical/Critical-Care/Article/08-26/Rural-Toxicology-Manure-Pits-Superwarfarins-Burns/81300