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Plant exposures are a common source of poisoning in the United States. The 2013 annual report of the American Association of Poison Control Centers' National Poison Data System (NPDS) reported a total 46,376 plant exposures in the United States for the year, 29,346 of them occurring in children aged 5 years or younger (reflecting exploratory ingestions in this age group).[1] Most plant exposures are benign, although serious morbidity and mortality can occur. The NPDS reported a total of three deaths attributed to plant exposures in the United States in 2013. Do you know how to best manage the following cases of plant poisoning?
Contact dermatitis caused by urushiol, an oil existing in the stems, roots, and leaves of Toxicodendron species, including poison ivy, poison sumac, and poison oak, is shown.
Image courtesy of Wikimedia Commons | Britannic124.
Answer: D. Philodendron
In this particular case, esophageal erosions and stricture developed in the child, followed by sudden death 17 days after exposure—thought to be due to vagotonia secondary to the esophageal lesions.[2] Owing to its common use as an ornamental houseplant, pediatric exploratory ingestions of Philodendron species are relatively common. The leaves of these plants contain raphides of oxalate, spindle-shaped crystals that cause mechanical irritation when chewed. Rarely, airway edema and obstruction may ensue. Ocular exposure causes pain, redness, and swelling. Other genera that share the philodendron's broad, showy leaves; raphides of oxalate; and clinical manifestations include Caladium, Dieffenbachia, and Spathiphyllum. Pictured on this page is C bicolor.
Image courtesy of Wikimedia Commons | Captain-tucker.
A 26-year-old flight attendant complains of a bilateral rash on her forearms 1 day after juicing the pictured fruit while preparing beverages for passengers. Cutaneous exposure to the juice of this plant is associated with which of the following eruptions?
Image courtesy of Wikimedia Commons | Matt.
Answer: D. Photodermatitis
Several plants are associated with photodermatitis, which in this setting is more specifically termed phytophotodermatitis. These plants contain photosensitizing chemicals called furocoumarins, a group of structurally related molecules that cause skin damage with exposure to ultraviolet light.[3,4] Responsible genera include Citrus (lime), Ficus (fig), Daucus (carrot), Cymopterus (parsley), and Pastinaca (parsnip), among others. The classic presentation is cutaneous exposure to one of these plants followed by ultraviolet light exposure (eg, harvesting crops on a sunny day), leading to a rash in sun-exposed areas after 24 hours. In this specific case, the flight attendant went sunbathing during a layover in the Caribbean after cutaneous exposure to lime juice, resulting in the findings shown.
Image courtesy of Medscape.
A 22-year-old man presents with confusion, agitation, and a waxing and waning level of consciousness. During intubation for airway protection, numerous dark brown foreign bodies are noted between his teeth. A bag containing similar dark brown "pellets" is found in his pocket. What medication might improve this patient's altered mental status?
Image courtesy of Wikimedia Commons | Danny S.
Answer: D. Physostigmine
This patient deliberately chewed the seeds of Datura stramonium (jimson weed) in an effort to induce an anticholinergic delirium.[5] Physostigmine may be useful in reversing anticholinergic delirium in such cases.[6] Datura remains a popular drug of abuse among adolescents. The seeds may be chewed or ingested, or a tea may be brewed using the leaves or seeds of the plant. Atropa and Brugmansia are other genera containing anticholinergic belladonna alkaloids. Pictured is the characteristic large, trumpet-shaped flower of plants in the Datura genus (a common name for the plant is angel's trumpet).
Image courtesy of Wikimedia Commons | John Fowler.
A 49-year-old man with a history of diabetes mellitus presents with altered mental status via ambulance. Vital signs include a temperature of 36.9°C (98.4°F), a heart rate of 40 beats per minute, a respiratory rate of 12 breaths per minute, and a systolic blood pressure of 80 mm Hg. His electrocardiogram (ECG) is shown. The patient's wife relates that he made a concoction out of the leaves of a plant as a treatment for his diabetes. Which of the following treatments would be most effective for this patient?
Image courtesy of Medscape.
Answer: A. Antidigoxin antibodies
The patient's ECG demonstrates bidirectional tachycardia, which is characteristic of cardiac glycoside poisoning. Nerium oleander (common oleander; pictured) contains cardiac glycosides similar to those found in digitalis and has been unwisely recommended on the Internet as a natural treatment for diabetes mellitus. Cardiac glycoside toxicity has been reported following inhalation of oleander smoke, use of oleander twigs to roast marshmallows, or ingestion of water into which oleander flowers were placed. Other plants containing cardiac glycosides include Digitalis species (foxglove), Convallaria majalis (lily-of-the-valley), and Thevetia peruviana (yellow oleander), among others. Significant cardiac glycoside poisoning due to any of these plants should be treated with antidigoxin antibodies.[7]
Image courtesy of Wikimedia Commons | Rüdiger Meier.
Two hours after picking and eating "wild carrots" growing in their backyard, a father brings his 4-year-old son in with a complaint of vomiting and unresponsiveness. On examination, the child withdraws to painful stimuli and is noted to have small, reactive pupils with disconjugate gaze. The remainder of the child's physical examination is unremarkable. The father has brought some of the "wild carrot" plant with him. What plant did he and his son inadvertently ingest?
Image courtesy of Wikimedia Commons | Karelj.
Answer: D. Poison hemlock
Although these patients meant to ingest Daucus carota (wild carrot; left image), they inadvertently ingested Conium maculatum (poison hemlock; middle image) instead.[8] Another poisonous plant resembling wild carrot is Cicuta virosa (water hemlock or cowbane; right image). Poison hemlock contains nicotinic alkaloids (eg, coniine), which cause a nicotinic toxidrome, whereas Cicuta toxicity prominently features seizures.
Images courtesy of Wikimedia Commons | Tigerente (left), Wikimedia Commons | Saxo (middle), Wikimedia Commons | H. Zell (right).
Answer: C. Delayed-type hypersensitivity
Plants in the genus Toxicodendron (previously known as the genus Rhus), such as eastern poison ivy (T radicans; as shown in the previous slide) and western poison ivy (T rydbergii), contain urushiol, a potent oil to which 80-90% of persons are capable of being sensitized.[9-11] Exposure typically results in a type IV hypersensitivity reaction (delayed-type hypersensitivity), with a characteristic rash that has sharp edges (shown). A commonly used mnemonic for these plants is "Leaves of 3, let it be!"; note, however, that poison sumac (T vernix) usually has clusters of 7-13 leaves.
Image courtesy of Medscape.
A 57-year-old man calls 911 from his hotel room with a complaint of respiratory distress. In the emergency department, he is unable to provide further history due to respiratory distress and requires endotracheal intubation for respiratory failure. He continues to have ventilator-dependent respiratory failure of unknown etiology for 2 weeks, when a family member picking up his belongings from the hotel room discovers an "anarchist-type textbook," the pictured seeds, and vials containing an unknown powder. Toxicity is likely due to exposure to what genus of plant?
Image courtesy of Wikimedia Commons | Slinger~commonswiki.
Answer: C. Ricinus
The castor bean, the seed of Ricinus communis, is shown on the previous slide. The seed contains ricin, a toxalbumin that interferes with ribosome function.[12] The features of toxicity depend on the route of exposure (ingestion, inhalation, or injection). Of note, when swallowed whole, the protective coating of the seed prevents human toxicity. Ricin is considered a potential weapon of mass destruction and has been used in assassinations and terrorist attacks.[13] Abrus precatorius (jequirity pea or rosary pea; shown) contains a similar toxalbumin in its red-and-black seeds. Use of these seeds in jewelry may result in pediatric exploratory ingestions.
Image courtesy of Wikimedia Commons | Forest & Kim Starr.
Answer: B. Gastrointestinal
Ilex is a plant genus containing more than 300 species, known colloquially as holly. The popularity of these species as ornamental plants in gardens and as components of holiday wreaths and other decorations contributes to pediatric exploratory ingestions. Their toxicity to humans is largely limited to nausea, vomiting, diarrhea, and abdominal pain. Treatment is supportive.
Image courtesy of Wikimedia Commons | Maksim.
An ECG was obtained (shown). What is the mechanism of toxicity associated with this plant?
Image courtesy of Nathanson LA, McClennen S, Safran C, Goldberger AL. ECG Wave-Maven: Self-Assessment Program for Students and Clinicians. http://ecg.bidmc.harvard.edu.
Answer: D. Sodium ion channel activation
The patient's ECG demonstrates atrial fibrillation with ventricular bigeminy. Aconitum (monkshood, aconite, wolfsbane), a genus of flowering plants that feature racemes of helmet-shaped flowers, causes sodium ion channel activation, resulting in muscarinic findings, neurologic complaints (eg, paresthesias), and cardiac toxicity similar to that produced by cardioactive steroids.[14] Other plant genera that cause sodium ion channel activation include Veratrum (false hellebore; left image), Rhododendron (rhododendron, azalea; right image), and Zigadenus (death camas), among others. Treatment is supportive. In contrast to plants containing cardioactive steroids (eg, Digitalis, Nerium), antidigoxin antibodies are ineffective in managing toxicity caused by these genera.
Images courtesy of Wikimedia Commons | SB Johnny (left), Wikimedia Commons | Qwert1234 (right).
A 4-year-old girl is brought in by her parents for evaluation following ingestion of this popular seasonal ornamental plant. The parents are anxious because they have heard that the plant is highly toxic and can cause death. The child has no complaints, normal vital signs, and a normal physical examination. Which of the following is the most appropriate treatment for this child?
Image courtesy of Wikimedia Commons | i'am.
Answer: D. Reassurance
Euphorbia pulcherrima, or poinsettia, developed a long-standing reputation for being highly toxic on the basis of a case report of a child fatality in 1919. However, accumulated experience since then has shown that poinsettia ingestions are largely benign, with mucous membrane irritation or gastrointestinal distress being reported only rarely.[15] Once the parents have been reassured, this child may be safely sent home with instructions to return if gastrointestinal distress develops.
Image courtesy of Wikimedia Commons | Scott Bauer.
A 2-year-old boy is found eating the leaves of this plant found in the family's backyard. In addition to gastrointestinal upset, which of the following laboratory abnormalities is expected to occur following ingestion?
Image courtesy of Wikimedia Commons | John B.
Answer: D. Lymphocytosis
Phytolacca americana, or pokeweed, an approximately 12-foot-tall plant native to the United States, is recognizable for its purple stems and clusters of purplish to black berries. When ingested, pokeweed causes gastrointestinal upset, including nausea, vomiting, diarrhea, and abdominal pain. Rarely, hemorrhagic gastritis, bradycardia, hypotension, and death may ensue. A plant component, pokeweed mitogen, produces a lymphocytosis that lasts 2-10 days after exposure. Interestingly, poke sallet (or poke salad) is a traditional Southern food, produced by parboiling the leaves or berries to reduce their toxin burden.
Image courtesy of Wikimedia Commons | Algirdas.
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