Few plants are associated with significant morbidity and mortality. An exception are the members of genus Datura.1,17 Datura stramonium is the most prevalent of the species in North America and is known commonly as jimsonweed.17 Other common names include angel's trumpet, devil's apple, Jamestown weed, la reina de la noche, locoweed, moonflower, stinkweed, and thornapple.17 The plants contain significant quantities of belladonna alkaloids, namely, atropine and scopolamine.17 Jimsonweed is an opportunistic plant and grows wild throughout the United States. The seeds are abused, especially by adolescents and teenagers, for to their psychotropic effects, but toxicity often occurs when the green leaves are mistaken for other edible plants.18 Patients with a significant ingestion will manifest an anticholinergic toxidrome: tachycardia, mydriasis, dry skin and mucous membranes, hypoactive bowel sounds, urinary retention, and hyperthermia. Central anticholinergic effects result in altered mental status, ranging from somnolence to severe agitation, delirium, and hallucinations.17,19 Symptoms usually arise within 30–60 minutes of ingestion and can persist for 24–48 hours.17 Approximately 80% will experience adverse effects.17 Minor agitation may respond to benzodiazepines. Hyperthermia should be treated supportively with cooling measures. Since the basis of toxicity is muscarinic antagonism, the use of a cholinesterase inhibitor such as physostigmine may help to restore autonomic balance and should be considered in patients with refractory delirium and agitation; however, there is ongoing controversy regarding its effect on clinical course and outcome and injudicious use may be complicated with cholinergic toxicity.17,20 Physostigmine may be used in pediatric doses of 0.02 mg/kg IV at a rate not to exceed 0.5 mg/min—it must not be administered rapidly or via IV push as seizures and arrhythmias may occur.17 If there is no improvement after 5–10 minutes, additional doses may be attempted, to a total of 2 mg. The dose for adolescents and adults is 0.5–2 mg IV administered no more rapidly than 1 mg/min.17 Physostigmine has a short half-life and the effects typically last for 30–60 minutes and repeat dosing may be required. A constant infusion of physostigmine should not be used.17 Patients with marked delirium, seizures, cardiopulmonary instability, or those treated with physostigmine should be admitted to an intensive care unit.
This group includes Digitalis purpurea (Foxglove)21, Convallaria majalis (Lily of the Valley),21 and Nerium oleander (Common Oleander).22 It is unlikely that the casual ingestion of plant parts will be toxic to children. The greatest risk comes when it is brewed as a tea and used as a home remedy or used with suicidal intention.21 If toxicity occurs, the child should be treated conventionally for digoxin toxicity. Supportive care and, if indicated, the administration of digoxin immune Fab may be beneficial.21 Unlike foxglove, the cardiac glycosides of the lily of the valley (convallatoxins) are less potent.21 If serious oleander toxicity develops, digoxin immune Fab may be effective.23
Other Plants With Toxic Potential
Taxus species (Yew): Yew plants contain the cardiotoxic alkaloids taxine A and B. Morbidity and mortality are associated with suicidal ingestions.24 A poison center review of over 11,000 largely pediatric yew exposures revealed that the majority of cases (92.5%) were asymptomatic, and no deaths were reported.25
Conium maculatum (Poison Hemlock): Poison hemlock contains coniine, as well as other nicotinic alkaloids.26 Manifestations of toxicity are similar to those observed with nicotine, with an initial stimulatory phase that may include tachycardia, diaphoresis, tremor, and seizures. The subsequent depressant phase may involve bradycardia, hypotension, muscular paralysis, and coma.26,27 Supportive care is the mainstay of therapy. Asymptomatic patients who present with a possible ingestion should be observed for a minimum of 4–6 hours.
Cicuta maculata and Cicuta douglasii (Water Hemlock): Water hemlock contains a variety of toxins, including cicutoxin, with the highest concentrations in the root.28 Cicutoxin is a highly potent convulsant. Patients may first suffer gastrointestinal symptoms and then rapidly develop seizures, progressing on to status epilepticus. Treatment consists of aggressive supportive care with early attention to definitive airway management and rapid escalation of anticonvulsant therapy (see Chapter 52). Asymptomatic patients should be observed closely for a minimum of 4–6 hours.