Resin Poisoning 

Plants have evolved highly complex systems of defense against most of their natural enemies (eg, insects, animals). At the very least, these defenses make many plants unpalatable; however, some can be fatal to the inexperienced forager.

Throughout human history, plants have played pivotal roles as medicines and poisons. Our medical predecessors may not have known the exact mechanisms involved, but they did recognize various plants as instrumental for medical treatment and as instruments of murder. With current technology, we finally are able to peer into plants and see their vast arsenal of chemicals, including glycosides, alkaloids, oxalates, and resins.

When considering poisoning by plant resin, always be aware of possible co-intoxicants, which may blur the clinical picture. Such co-intoxicants include pharmaceutical and illicit drugs, herbicides, fungicides, insecticides, fertilizers, and artificial plant hormones.

Examples of unintentional toxic plant ingestion include the following:

• Hikers who mistake poisonous plants for nutritious ones
• Herbalists who seek natural remedies or natural highs and end up with poisonous concoctions
• Children who are attracted to brightly colored fruits and leaves of poisonous plants (This group accounts for the most calls to poison centers regarding plant toxicity.)

Resins are a diverse group of chemical compounds that share chemical characteristics, such as insolubility in water, solidity at room temperature, and lack of nitrogen group. Resin compounds formed with sugars are called glycoresins; those formed with oils are called oleoresins. Latex is a term used to describe these toxins when found in emulsions (ie, urushiols, which are catechol derivatives) in ducts of plants. They are released and activated when structural damage to the plant occurs.

Frequency

United States

While some individuals ingest toxic plants to attempt suicide, most present to the ED after unintentional toxic plant ingestion.

The 2006 Annual Report of the American Association of Poison Control Centers' National Poison Data System (NPDS) documented 64,236 plant exposures (2.7% of total human exposure).^[1] This figure is lower than that of 2004 (documented 74,811); however, the overall number of all types of human exposures remain little changed in the past 6 years.^[2]

Pediatric (children < 5 years old) plant exposures in 2006 were noted to be 44,710 or 3.7% of pediatric exposures reported.

The following is a list of the 25 most commonly reported plant involved in a reported exposure in 2006 NPDS:

• Spathiphyllum species - 2,133
• Euphorbia pulcherrima - 1,615
• Ilex species - 1,572
• Philodendron species - 1,514
• Phytolacca americana - 1,358
• Toxicodendron radicans - 1,194
• Schlumbergera bridgesii - 705
• Ilex opaca - 608
• Crassula argentea - 604
• Plants-cardiac glycosides - 583
• Malus species - 582
• Taraxacum officinale - 581
• Pepper mace - 566
• Epipremnum areum - 566
• Plants, cyanogenic glycosides - 555
• Plants, pokeweed - 543
• Mold - 538
• Caladium species - 533
• Nandina domestica - 530
• Narcissus pseudonarcissus - 474
• Spinacia oleracea - 467
• Cactus (unknown type or name) - 460
• Rosa species - 450
• Quercus species - 447
• Hedera helix - 446

Mortality/Morbidity

Five deaths were reported in 2004, which represents 0.007% of all plant exposures.

• Of all plant exposures reported, only 30% had outcomes reported. Sixty-six percent of the reported outcomes were asymptomatic.
• Ninety-five percent of all plant exposures reported were unintentional.

Age

Approximately 74% of plant exposures reported to poison centers in 2004 involved children younger than 6 years.