Plants, Herbal Medications, and Mushrooms

Foundations

The nutritional, therapeutic, psychoactive and toxic properties of botanicals have made their usage pervasive since antiquity. The earliest documented use of plants for medicinal purposes can be found in Sumerian clay tablets that describe the use of over 200 different plants in the treatment of various maladies. Ancient Greeks recognized the lethal effects of botanicals, sentencing Socrates to death by ingestion of a poison hemlock-based liquid. The recreational abuse and medicinal use of opium poppies highlight the wide-ranging role plants have played throughout history.

Exposures to plants comprise over 42,000 calls nationally to US poison centers, with over half of cases involving pediatric patients less than 6 years of age. Over 85% of plant exposures are accidental ingestions. The overwhelming majority of plant exposures result in minimal toxicity and death is exceedingly rare. Plant exposures reported to US poison centers have been decreasing over the past three decades, ranking 3rd and comprising 9% of all exposures in 1983, but ranking 22nd and making up only 2% of all exposures in 2018. The most common plant exposures resulting in severe and occasionally fatal poisonings involve those with anticholinergic, antimitotic, cardiotoxic or convulsive properties.

Clinical Features

The vast majority of plants are considered non-toxic ( Table 153.1 ). However, serious toxicity can result from certain plant exposure ( Table 153.2 ). Toxicity does not correlate well with taxonomy, and plants within the same genera may have varying toxic profiles. Further complicating matters, the severity of exposure may depend on the method of exposure (chewed, swallowed, smoked or injected) and which part of the plant was ingested (berries, leaves, or stems). For example, although all parts of the water hemlock plant are considered toxic, cicutoxin is most concentrated in the root of the plant. The majority of serious or fatal outcomes occur when adults intentionally consume botanicals for suicidal or recreational intent. A focused history and physical exam should be aimed at identifying the etiology of the present illness and to identify any toxidrome common to botanical exposures.

Differential Diagnoses

Patients with plant ingestions present with vomiting and diarrhea and should be differentiated from food poisoning, viral or bacterial gastroenteritis, and pesticide poisoning (often sprayed on plants). Those patients presenting with altered mental status should be differentiated from patients co-ingesting hallucinogenic, stimulant, or opioid drugs of abuse.

Diagnostic Testing

Although specific concentrations of botanical toxins are not routinely available at most institutions, evaluation of electrolytes, renal and liver functions, transaminases, and complete blood count should be performed in patients with potentially toxic exposures. An electrocardiogram (ECG) and cardiac monitoring should be performed to identify any dysrhythmias. Efforts at botanical identification should be made to determine the potential toxicity of any exposure. Patients should not be routinely relied upon for botanical identification. Mistaken identification by patients and family members is a frequent cause of accidental ingestion of toxic botanicals and can lead to toxicity and inappropriate disposition from the emergency department (ED). Most emergency medical staff struggle to correctly identify even common house plants. Instead, family members or friends should be asked to bring in or send digital photographs of the involved plant, which can then be compared to reliable reference photographs or sent to local botanical experts or regional poison centers for proper identification.

Management

Ipecac for forced emesis and gastric lavage in botanical poisoning is not indicated. There is little evidence of clinical benefit of activated charcoal, and we do not recommend its routine use in botanical poisoning. A few exceptions can be made in patients who present within 1 hour of ingestion of a potentially life-threatening exposure (see Table 139.12).

There are few antidotes that have been shown to be effective in botanical poisonings. In most exposures, information and identification of the plant is not immediately known and treatment should be focused on symptom-based, supportive care. This includes maintenance of a patent airway, intravenous fluids and vasopressors for hypotension, active cooling for hyperthermia, and benzodiazepines for agitation and seizures. Management of specific categories of botanicals is outlined in the following sections.

Disposition

Any patient with signs of severe toxicity, especially those involving the cardiovascular and neurologic systems, should be managed in the ED until symptoms and signs are resolving, or they are admitted to an intensive care setting. Patients with exposure to unknown plants can be discharged after 6 hours of cardiac monitoring if they are hemodynamically stable and otherwise asymptomatic. This period of observation should be extended to 24 hours if pre-existing cardiovascular or other concerning medical problems exist or an exposure to a plant of serious toxicity is suspected.

Plant Categories

Anticholinergics

Foundations

Principles of toxicity

Datura stramonium (Jimson weed, angel’s trumpet) ( Fig. 153.1 ) and Atropa belladonna (deadly nightshade) are the most frequently encountered plants with anticholinergic toxins. They contain scopolamine, hyocyamine and atropine. All parts of the plant contain toxic alkaloids, but they are most concentrated in the seeds of D. stramonium and the fruit and leaves of A. belladonna .

Clinical features

Ingestion can cause the antimuscarinic syndrome of agitation, diminished gastrointestinal (GI) motility, dry skin, flushing, hallucinations, hyperthermia, mydriasis, tachycardia, and urinary retention. ^, D. stramonium is commonly abused for its hallucinogenic properties, whereas berries from A. belladonna have been mistaken for the common blueberry (Vaccinium arctostaphylos) resulting in poisonings.

Differential diagnoses

The differential diagnosis of antimuscarinic toxicity includes toxicity from pharmaceutical agents such as diphenhydramine, benztropine, cyclic antidepressants, antipsychotics, and antiparkinson medications. Sympathomimetic drugs such as cocaine and amphetamines will also cause similar toxic symptoms but typically present with diaphoresis instead of dry skin, which is typical of the antimuscarinic toxidrome.

Diagnostic testing

Symptomatic patients with altered mental status or abnormal vital signs should have a screening ECG to assess corrected QT (QTc) and QRS intervals, serum electrolytes, glucose, creatinine phosphokinase (CPK) and renal function.

Management

Management should be focused on supportive care, including active cooling for hyperthermia and benzodiazepines for agitation. Recommended agents include diazepam, 5 to 10 mg IV, or lorazepam, 1 to 2 mg IV. Additional doses can be administered every 10 minutes until the patient is calm and able to cooperate with care. The use of a cholinesterase inhibitor, such as physostigmine (0.5 to 2 mg in adults; 0.02 mg/kg in children), is recommended for severe anticholinergic toxicity (see Chapter 140).

Disposition

Mildly symptomatic patients can be observed in the ED for 6 to 8 hours and discharged from the ED. Severely poisoned patients with refractory antimuscarinic symptoms should be admitted to a monitored setting for 24 hours.

Cardiac Glycosides

Foundations

Principles of toxicity

Cardiac glycosides bind to cell transmembrane Na ⁺ -K ⁺ -ATPases, which, in turn leads to a rise in intracellular Ca ²⁺ concentrations, causing decreased automaticity and increased contractility. Common plants that contain cardiac glycosides include Convallaria maalis (lily of the valley), Digitalis spp. (foxglove) ( Fig. 153.2 ), Nerium oleander (common, pink or white oleander) ( Fig. 153.3 ), and Thevetia peruviana (yellow oleander).

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