MMH ED Poison Center: Anti-cholinergic syndrome

Substance

Typical substances: Atropine, Scopolamine, Promethazine, Antihistamines (e.g., Diphenhydramine), Antipsychotics (e.g., Clozapine), Muscle relaxants (e.g., Cyclobenzaprine), Tricyclic antidepressants (e.g., Amitriptyline, Nortriptyline), Toxic plants (e.g., Datura曼陀羅屬, Deadly Nightshade, Atropa belladonna 顛茄). [1], [2], [3]

Common Name

Also known as: Anticholinergic drugs, toxic plants (natural belladonna alkaloids), and antispasmodic agents. Drug for motion sickness. [4]

Occasionally observed side effects caused by the combination of anti-motion sickness patches and motion sickness medication during outdoor field trips in Taiwan.

Involving System[5]

Central Nervous System (CNS): Agitation, delirium, hallucinations, seizures.

Cardiovascular system: Tachycardia, hypertension.

Respiratory system: Potential respiratory depression. Suppress the central nervous system (CNS) in severe overdose cases, leading to respiratory depression. Bronchodilation, this effect is generally beneficial in conditions like asthma but is not typically clinically significant in overdose.

Urinary system: Urinary retention.

Gastrointestinal system: Dry mouth, decreased bowel motility.

Eyes: Mydriasis (dilated pupils), blurry vision.

Presentation[1] [5]

Clinical features:

"Dry as a bone": Dry mouth and skin.

"Red as a beet": Flushed skin.

"Hot as a hare": Hyperthermia.

"Blind as a bat": Dilated pupils and blurred vision.

"Mad as a hatter": Agitation, delirium, hallucinations.

"Full as a flask": Urinary retention.

Decreased bowel sounds or constipation.

Many anticholinergics cannot be directly detected. To trace the contact or medical history

Antidote [6]

Physostigmine, Neostigmine, 0.5-2 mg as needed, total max.＜5 mg

Mechanism of action: Reversible acetylcholinesterase inhibitor that increases acetylcholine levels to counteract anticholinergic effects.

Caution: Only for severe central nervous system symptoms (e.g., delirium, seizures) and should be used carefully to avoid inducing arrhythmias or seizures.

Delirium: 0.8 to 1.2 mg. [7]

Symptomatic treatment:

Cooling measures (e.g., ice packs or cooling blankets).

Cardiovascular support (e.g., beta-blockers for tachycardia).

Sedatives (e.g., benzodiazepines) for agitation or seizures.

Disposition[8]

Observation and admission:

Mild cases: Observe for 6-12 hours.

Moderate to severe cases: Admit to the hospital for treatment, including intensive care monitoring if necessary.

Follow-up management:

Provide psychiatric evaluation if poisoning is due to intentional overdose or substance abuse.

Educate patients to avoid repeated exposure to the toxin.