Don’t Eat That: Tips to Care for Patients with Toxic Exposures

Nurses who care for patients with toxic exposures need to be quick-thinking, collaborative and be able to effectively use available resources. Kathrine Huff, MS, RN, who works in the coronary intensive care unit (CICU) at Cleveland Clinic main campus, shares her knowledge regarding toxic exposure cases.

“Patients with toxic exposure can be difficult to manage for a number of reasons,” Huff says. “Nurses may not know what the patient was exposed to, there could be endless potential causes that are hard to narrow down, and, in some cases, a patient may present one way initially and another way later.”

Huff recalls a toxic exposure case her colleagues faced not long ago. A patient came to Cleveland Clinic’s main campus ED with complaints of nausea, vomiting and diarrhea. The patient mentioned recently eating mushrooms that were foraged from the local environment. Immediately, the patient was transferred to the medical intensive care unit with a proposed diagnosis of ingestion of the Amanita phalloides, also known as the “death cap” mushroom. The toxins within a single death cap mushroom far exceed the lethal dose for an adult.

With Amanita phalloides mushroom ingestion, patients first present with malaise, fatigue, abdominal pain and vomiting. In phase two, the symptoms almost appear to go away, but liver damage is occurring. By phase three the effects can be anything from intracranial hemorrhage, hepatic encephalopathy, coagulopathies and cerebral edema to kidney failure, ARDS, impaired immune function and lactic acidosis.

“Unfortunately, we see a high mortality rate with these patients because they delay getting medical help due to the way the toxins present,” Huff says. “Many people don’t go to the ED until they are already in acute liver failure.”

In this case, the medical ICU team moved quickly to treat the patient. Through support from the Poison Control Center, they were able to administer the patient an investigational drug for emergency use. They also provided Molecular Adsorbent Recirculation System (MARS) therapy. The patient had an orthotopic liver transplant four days after ingestion and was discharged in 17 days.

To help nurses manage challenging toxic exposure cases, Huff recommends the following:

1. Know the toxicology basics.
2. Assess toxic exposure patients using six key components.
3. Understand the five classical toxidromes.
4. Partner with Poison Control Centers.

Toxicology basics

Toxicology looks at the adverse effects a substance has on living beings. Essentially, any substance, such as manmade or naturally occurring chemicals, can be a poison at the right dose. Dosing is an important component of toxicology. Huff says there are three common dosing terms.

• ED50 or effective dose: produces the desired result in 50 percent of the population.
• TD50 or toxic dose: produces a specific toxicity in 50 percent of the population.
• LD50 or lethal dose: dose that is lethal in 50 percent of the population.

She adds that the therapeutic index for dosing is calculated by dividing TD50 by ED50, which provides crucial guidance for determining the relative safety of a drug.

Assess toxic exposure patients using 6 key components

Huff suggests nurses assess for:

• effect on heart rate
• effect on respiratory rate
• hypothermia or hyperthermia
• pupil dilation or constriction
• hyperactive or hypoactive/absent bowel sounds
• diaphoretic/wet or extremely dry

Understand the 5 classical toxidromes

As drug design has evolved recreationally and medically, toxidromes have expanded. However, Huff says nurses should know these classical toxidromes.

• Opioid Toxidrome. This includes natural, semi-synthetic and synthetic opioids. Patient assessment is “depressed,” including hypothermic body temperature, hypoactive or absent bowel, and dry skin. Overall clinical picture is CNS and respiratory depression, as well as altered mental status, confusion, bordering on comatose.
• Sedative-Hypnotic Toxidrome. This includes anticonvulsants, benzodiazepines, alcohol, barbiturates and z-drugs. Clinical picture is similar to opioid toxidrome, but respiratory depression isn’t as extreme, and eyes may have no pupillary change. Patients will likely have signs of delirium and/or hallucinations.
• Sympathomimetic Toxidrome. This includes amphetamines, ephedrine and drugs considered stimulants. Patient assessment is “up,” including hyperthermia, dilated pupils, hyperactive bowel, wet and diaphoretic. Patient will likely have altered mental status with increased panic, agitation and possible seizures.
• Anticholinergic Toxidrome. This includes antihistamines, antidepressants, antipsychotics, plants (i.e. Jimson weed) and atropine. Increased heart rate is most notable symptom and respiratory rates don’t typically change. Assessment should also incorporate the mnemonic: MAD as a hatter, HOT as a hare, DRY as a bone, RED as a beet, BLIND as a bat, FULL as a flask.
• Cholinergic Toxidrome. This includes physostigmine, pesticides, nerve agents and muscarinic mushrooms. Clinical picture is distinct: no real change in heart rate or body temperature, decreased pupil size, increased bowel sounds, extreme wetness. In addition, symptoms from interaction with muscarinic receptors follow SLUDGE: Salivation, Lacrimation, Urination, Defecation, GI upset and Emesis. Nicotinic receptors follow the “Days of the Week”: Muscle cramps, Tachycardia, Weakness, Twitching and Fasciculations. Patients require aggressive decontamination and rapid treatment.

“Toxidromes are a helpful starting point for treatment, but their clinical presentation may not be so straightforward. Many complicating factors may be at play, such as situations where more than one toxicant is present, unknown challenges related to new and evolving designer drugs, and patients with comorbidities or who are taking other medications that can make the diagnosis even harder,” says Huff.

Partner with poison control centers

Huff’s final recommendation for nurses caring for toxic exposure patients is to partner with local poison control centers. There are 55 in the United States that collaborate to provide free services nationwide, 24 hours a day, 7 days a week, 365 days a year.

“Among other benefits, poison control centers offer a wealth of information in a rapid and timely manner, allow for early intervention of toxicities, provide access to nurses, pharmacists, physicians and board-certified toxicologists, help nurses manage patients with the best outcomes, and prevent costs to healthcare facilities and shorten hospital stays,” says Huff.

She adds that poison control centers are HIPAA compliant, so nurses can discuss the finer details of patient cases with center representatives. Nurses can text POISON to 797979 for the contact information of their local poison control center, visit poisonhelp.org, or call the poison help line at 800.222.1222.