Poisonings and Toxic Exposures

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What is the phone number for the Poison Control Center?

According to the American Association of Poison Control Centers, the Poison Help hotline, 1-800-222-1222, connects callers to their local poison control center anywhere in the United States and its territories. An interactive online tool is also available at www.poisonhelp.org . The Poison Control Center can help with pill identification.

2

Name some drugs and household products that, when taken in small quantities, are potentially lethal to small children.

• Antimalarials

• Antidysrhythmic drugs

• Benzocaine

• Beta-blockers

• Calcium channel blockers

• Camphor

• Clonidine and similar pharmaceuticals

• Diphenoxylate with atropine

• Lindane

• Methanol

• Methyl salicylate

• Opioids

• Sulfonylureas

• Theophylline

• Tricyclic antidepressants

Case: EMS is called for an altered mental status case. The family reports that the patient may have overdosed on medication or used a recreational drug.

3

Where does one start when evaluating an overdose patient?

One starts by examining the patient. Particular attention is paid to the vital signs (blood pressure, heart rate, respiratory rate, and temperature) and to other physical exam findings such as the mental status (depressed, agitated, hallucinating), pupil size (pinpoint or dilated), skin (dry vs. moist axillae), mucous membranes (dry vs. moist), gastrointestinal (GI) system (presence or absence of bowel sounds, presence of diarrhea), and urinary system (presence of a distended bladder or evidence or urinary incontinence).

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What is a “toxidrome?”

The group of physical exam findings and symptoms that are characteristically associated with a certain type of toxicant is known as a toxidrome. Thus, one does not necessarily need to know the specific toxicant when providing initial care to the poisoned patient.

Case (continued): The patient has a depressed mental status. His pupils are noted to be small. He is breathing 4–6 times a minute. A belt is around the left arm and there is an empty syringe nearby.

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What toxidrome does this describe? What is the antidote and what are the indications for use?

The opioid toxidrome is classically characterized by the triad of miosis, mental status depression, and respiratory depression. These signs are not always consistently present. The most important sign is respiratory depression, which can progress to apnea, hypoxia, and death. Naloxone should be given to those who are suspected of having overdosed on an opiate AND have respiratory depression. Those who have been exposed to a substance that is suspected to be an opiate who have nonspecific symptoms without respiratory depression should not be treated with naloxone.

Case: The patient appears to be having visual hallucinations, he has mumbling speech, and he is picking in the air and at his clothing. He is tachycardic and hypertensive. His axillae and mucous membranes are dry and his skin is hot and flushed. His pupils are markedly dilated. An empty bottle of over-the-counter allergy medication is found nearby.

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What toxidrome does this describe?

The anticholinergic (antimuscarinic) toxidrome occurs when the effect of acetylcholine at the muscarinic receptor is antagonized. It is characterized by anhidrosis (dry skin), mydriasis (dilated pupils), flushing, hyperthermia, and delirium. Urinary retention is common and may contribute to a patient’s agitation. Features are variably present. There are several medications that can cause anticholinergic toxidrome, including atropine, hyoscyamine, and scopolamine. Anticholinergic features are common in overdose of antihistamines, antipsychotics, and tricyclic antidepressants. BZ (3-quinuclidinyl benzilate) was developed as a potential anticholinergic incapacitating agent.

Case: The patient is agitated, tachycardic, and hypertensive. He is markedly diaphoretic. He reportedly was smoking a crystalline substance.

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