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Author: Jason Kearney, MD, Consulting Staff, Department of Emergency Medicine, Emergency Medicine Associates

Jason Kearney is a member of the following medical societies: American Academy of Emergency Medicine

Coauthor(s): William K Chiang, MD, Associate Professor, Department of Emergency Medicine, Department of Emergency Medicine, New York University School of Medicine; Consulting Staff, Bellevue Hospital Center

Editors: Miguel C Fernandez, MD, FAAEM, FACEP, FACMT, Associate Clinical Professor; Medical and Managing Director, South Texas Poison Center, Department of Surgery/Emergency Medicine and Toxicology, University of Texas Health Science Center at San Antonio; John T VanDeVoort, PharmD, ABAT, Director of Pharmacy, Sacred Heart Hospital; Michael Hodgman, MD, Assistant Clinical Professor of Medicine, Department of Emergency Medicine, Bassett Healthcare; John Halamka, MD, Chief Information Officer, CareGroup Healthcare System, Assistant Professor of Medicine, Department of Emergency Medicine, Beth Israel Deaconess Medical Center; Assistant Professor of Medicine, Harvard Medical School; Asim Tarabar, MD, Assistant Professor, Department of Surgery, Section of Emergency Medicine, Yale University School of Medicine; Consulting Staff, Department of Emergency Medicine, Yale-New Haven Hospital

Author and Editor Disclosure

Synonyms and related keywords: oxalate crystals, oxalate exposures, Philodendron, Dieffenbachia, Anthurium, Anthurium species, Arum, Araceae, Arisaema species, Caladium, Caladium bicolor, Calla lily, Zantedeschia species, Chinese evergreen, Aglaonema species, Dieffenbachia, Dieffenbachia species, Jack-in-the pulpit, Arisaema triphyllum, Monstera, Ceriman, Monstera deliciosa, Nephthytis, Syngonium podophyllum, Philodendron, Philodendron species, Pothos or Hunter's robe, Epipremnum aureum, skunk cabbage, Symplocarpus foetidus

Background

Plant exposures are some of the most frequent poisonings reported to poison control centers. Exposures to plants containing oxalate crystals, such as Philodendron and Dieffenbachia, are among the most common toxic plant exposures reported in the US.

For the past 200 years, the irritant properties of the Dieffenbachia plant have had various uses, including punishing slaves and treating gout, impotence, and frigidity. Today, plants containing oxalate are admired for their ornamental beauty and found in public places and homes.

The following plants contain oxalates:

  • Anthurium (Anthurium species)
  • Arum, Araceae (Arisaema species)
  • Caladium (Caladium bicolor)
  • Calla lily (Zantedeschia species)
  • Chinese evergreen (Aglaonema species)
  • Dieffenbachia (Dieffenbachia species) (see Media file 1)
  • Jack-in-the pulpit (Arisaema triphyllum) (see Media file 2)
  • Monstera, Ceriman (Monstera deliciosa)
  • Nephthytis (Syngonium podophyllum)
  • Philodendron (Philodendron species)
  • Pothos or Hunter's robe (Epipremnum aureum)
  • Skunk cabbage (Symplocarpus foetidus) (see Media files 3-4)

Pathophysiology

Nonsoluble calcium oxalate crystals are found in plant stems, roots, and leaves. The stalk of the Dieffenbachia plant produces the most severe reactions. These needlelike crystals produce pain and edema when they contact lips, tongue, oral mucosa, conjunctiva, or skin. Edema primarily is due to direct trauma from the needlelike crystals and, to a lesser extent, by other plant toxins (eg, bradykinins, enzymes).

Frequency

United States

Philodendron and Dieffenbachia exposures are among the most common plant exposures reported to poison control centers.

Mortality/Morbidity

In most cases, nonsoluble oxalate plants produce self-limited symptoms and clinical manifestations. Significant morbidity or mortality is extremely rare. One case report of an infant fatality attributed to airway obstruction after exposure to Dieffenbachia exists.

Age

The majority of oxalate plant exposures occur in children younger than 5 years while sampling houseplants in the home.



History

Symptoms, if they develop, occur rapidly and may include the following:

  • Keratoconjunctivitis and corneal abrasions after contact with plant material
  • Edema, erythema, bullae, and inflammation of mouth and oral mucosa after contact; esophagitis
  • Slurred or unintelligible speech
  • Laryngeal edema (with sufficient contact)
  • Superficial necrosis developing days after initial contact
  • Local skin erythema and/or edema (typical of a contact dermatitis) due to contact with plant sap or juices

Physical

No physical findings exist in the majority of oxalate exposures.



Angioedema
Conjunctivitis
Corneal Abrasion
Dermatitis, Contact
Plant Poisoning, Glycosides - Cardiac
Plant Poisoning, Glycosides - Coumarin
Plant Poisoning, Herbs
Plant Poisoning, Hypoglycemics
Plant Poisoning, Licorice
Plant Poisoning, Resins
Stevens-Johnson Syndrome

Other Problems to be Considered

Caustic ingestions



Prehospital Care

  • Decontaminate mouth, eye, and skin by physically removing all plant material.
  • Treat eye and skin exposure with copious water irrigation.
  • Rescuers should protect themselves from contact with plant materials.

Emergency Department Care

Most exposures are self-limited and only require analgesics for patient comfort.

  • For oral exposures, physically remove any plant material in the oral cavity.
    • Assess for any airway compromise.
    • Individuals without airway compromise can drink cold liquids and eat crushed ice, ice cream, or frozen ice pops or desserts for relief.
    • Oral swishing with diphenhydramine elixir provides local anesthetic and antihistaminic effects.
    • Individuals with laryngeal edema may be treated with antihistamines and observed and/or admitted until edema improves.
    • No clinical data support use of steroids in laryngeal edema induced by oxalate-containing plants.
  • Treat eye exposures with copious water irrigation. Employ slit lamp examination and fluorescein staining to rule out corneal involvement.
  • Skin exposures require irrigation with fluid and local wound care. Some individuals may develop a contact dermatitis.

Consultations

Nearly all cases of houseplant exposures involving oxalate-containing plant species are managed at home in consultation with a regional poison control center. Poison control centers may be helpful with plant identification, particularly if a fax copy or digital picture of the plant can be transmitted.



Analgesics may be required for pain.

Drug Category: Analgesics

Pain control is essential to quality patient care. Analgesics ensure patient comfort, which is beneficial for patients who have sustained trauma or sustained injuries.

Drug NameAcetaminophen (Tylenol)
DescriptionDOC for pain in patients with documented hypersensitivity to aspirin or NSAIDs, with upper GI disease, or who are taking oral anticoagulants.
Adult Dose650 mg PO/PR q4h prn
Pediatric Dose15 mg/kg/dose PO/PR q4h prn
ContraindicationsDocumented hypersensitivity
InteractionsRifampin can reduce analgesic effects of acetaminophen; coadministration with barbiturates, carbamazepine, hydantoins, and isoniazid may increase hepatotoxicity
PregnancyB - Fetal risk not confirmed in studies in humans but has been shown in some studies in animals
PrecautionsHepatotoxicity possible in patients with chronic alcoholism following various dose levels; severe or recurrent pain or high or continued fever may indicate serious illness; APAP is contained in many OTC products and combined use with these products may result in cumulative APAP doses exceeding recommended maximum dose (4 g/d)

Drug NameIbuprofen (Motrin, Advil)
DescriptionDOC for patients with mild to moderate pain. Inhibits inflammatory reactions and pain by decreasing prostaglandin synthesis.
Adult Dose200-600 mg PO qid prn
Pediatric Dose5-10 mg/kg PO q6h prn
ContraindicationsDocumented hypersensitivity; peptic ulcer disease, recent GI bleeding or perforation; renal insufficiency; high risk of bleeding
InteractionsCoadministration with aspirin increases risk of inducing serious NSAID-related adverse effects; probenecid may increase concentrations and, possibly, toxicity of NSAIDs; may decrease effect of hydralazine, captopril, and beta-blockers; may decrease diuretic effects of furosemide and thiazides; monitor PT closely (instruct patients to watch for signs of bleeding); may increase risk of methotrexate toxicity; phenytoin levels may be increased when administered concurrently
PregnancyB - Fetal risk not confirmed in studies in humans but has been shown in some studies in animals
D - Fetal risk shown in humans; use only if benefits outweigh risk to fetus
PrecautionsCategory D in third trimester of pregnancy; caution in congestive heart failure, hypertension, and decreased renal and hepatic function; caution in anticoagulation abnormalities or during anticoagulant therapy

Drug Category: Antihistamines

Treatment for significant oral and/or laryngeal edema.

Drug NameDiphenhydramine (Benadryl)
DescriptionFor symptomatic relief of symptoms caused by release of histamine.
Adult Dose25-50 mg PO/IV/IM q6h
5 mL of diphenhydramine elixir as oral swish q2h prn
Pediatric Dose5 mg/kg/d PO/IV/IM divided qid
ContraindicationsDocumented hypersensitivity; MAOIs
InteractionsPotentiates effect of CNS depressants; because of alcohol content, do not give syrup dosage form to patient taking medications that can cause disulfiramlike reactions
PregnancyC - Fetal risk revealed in studies in animals but not established or not studies in humans; may use if benefits outweigh risk to fetus
PrecautionsMay exacerbate angle-closure glaucoma, hyperthyroidism, peptic ulcer, and urinary tract obstruction; first trimester of pregnancy



Further Inpatient Care

  • Most oxalate exposures are self-limited and do not require any follow-up.
  • Patients with eye involvement should follow up with an ophthalmologist.

Prognosis

  • Most patients completely recover.



Medical/Legal Pitfalls

  • Confusion between oxalate-containing plants and other plants
    • Symplocarpus foetidus (skunk cabbage) may be easily confused with Veratrum viride (false hellebore), which may cause significant bradycardia and hypotension.
    • Other important plants that may cause significant toxicity include Nerium oleander (oleander), Phytolacca americana (pokeweed), Cicuta maculata (water hemlock), and Datura stramonium (Jimson weed).



Media file 1:  Dieffenbachia
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Media type:  Photo

Media file 2:  Jack-in-the-Pulpit
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Media type:  Photo

Media file 3:  Skunk Cabbage
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Media type:  Photo

Media file 4:  Skunk Cabbage
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Media type:  Photo



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Plant Poisoning, Oxalates excerpt

Article Last Updated: Aug 7, 2007