consultant on call TOXICOLOGY The 10 MOST TOXIC Plants Eric Dunayer,MS,VMD,ASPCA Animal Poison Control Center,Urbana,Illinois from the gastrointestinal tract. Other treat- Clinical Signs ver their evolution, plants have ments are aimed at controlling such signs • Initially, vomiting, anorexia, and lethargy developed numerous toxic agents as vomiting, diarrhea, and arrhythmias. starting within hours of ingestion; vomit- to protect themselves from being O ing may subside by 12 hours. eaten; many of these substances are LILIES • Renal values (blood urea nitrogen, creati- extremely poisonous. Even plants that are Various members of the Lilium genus, nine, and phosphorus) and potassium considered nontoxic—that is, ingestion including Easter lilies (L. longiflorum), tiger levels begin to increase by 24 to 72 should not cause serious systemic signs— lilies (L. lancifolium), stargazer lilies (L. hours. may result in vomiting and other gastroin- auratum), and various species of day lilies • Renal epithelial tubular casts and gluco- testinal disorders. The plants discussed in (Hemerocallis species); depending on the suria can be seen within 18 hours. this article are considered to be among the species, the flower’s stem is about 1 to 8 Treatment most toxic for dogs and cats; serious illness feet tall uncut. • Decontamination; fluid diuresis—twice and death can result from consumption of • Occur wild throughout North America. maintenance amounts for at least 48 relatively small amounts. These plants are • Commonly sold as cut flowers or as part hours commonly found in the home or yard. of floral arrangements; day lilies are a Prognosis common landscaping plant. • Guarded with delayed onset of treatment Identification of a plant may be difficult. • Toxicosis occurs only in cats. (24 hours or greater) and in presence of Plants have common names that may differ Principal Toxin oliguria/anuria. between various regions of the country. In • Unknown • Renal function can return but may take some cases, plants of different species may • All parts of the plant are toxic (even the weeks; chronic renal failure may be share common names, making determina- pollen). sequela. tion of a genus or species important for • Causes acute renal failure secondary to proper identification. If necessary, nursery continues acute tubular necrosis. personnel or a florist can be consulted to help identify the plant. GENERAL TREATMENT CONSIDERATIONS All cases of toxic plant ingestion are best treated by early, aggressive decontamina- tion. (See Procedures Pro, November 2004, pages 65-70.) Attempts at emesis should be made in asymptomatic patients, followed by administration of activated charcoal. Charcoal administration can be repeated every 4 to 6 hours while plant matter remains in the gastrointestinal tract. An enema given about 6 to 12 hours after ingestion may further clear plant matter Stargazer lily (L. auratum) Day lily (Hemerocallis) consultant on call ......................................................................................................................NAVC clinician’s brief....march.2005.....11 consultant on call CONTINUED CASTOR BEAN Prognosis • Neurotoxic effects can be seen but these • Good with prompt decontamination; may be secondary to hepatic failure. guarded once signs develop • Clinical pathology includes thrombocy- topenia, bilirubinemia, elevated hepatic CYCAD PALMS enzymes, and azotemia. Pathology • Liver has a nutmeg appearance. • Acute centrolobular hepatic necrosis occurs. • Fibrosis, bile stasis, and fatty changes develop over time. • Petechial hemorrhage and renal tubular necrosis are also seen. Castor bean plants (Ricinus communis) Treatment Ricinus communis • Symptomatic and supportive care for gas- (castor bean plant); trointestinal and hepatic signs (antiemet- also known as cas- ics, gastrointestinal protectants, such as tor oil plant, mole sucralfate, adenosyl for liver signs) bean, wonder tree Prognosis • Occurs in the • Poor once hepatic necrosis has occurred South, South- west, and RHODODENDRON, AZALEA, LAUREL California; may Castor beans be wild or culti- Sago palm (Cycas revoluta) Courtesy Dr. Camilla Lieske vated for castor oil; plants can stand 3 to 14 feet tall and have large leaves (12 Many species, but principally sago palm inches or greater). (Cycas revoluta) and fern palm/false sago • The beans are used as decorative beads. palm (C. circinalis); size varies with species Principal Toxin and can range from 6 to 30 feet tall with • Ricin, a glycoprotein long leaves (up to 9 feet). • Blocks protein synthesis, leading to cellu- • Used as ornamental plants in Florida and lar death. occasionally in California; can be house- • Is present in all parts of the plant but plants in northern climates. most concentrated in the beans. • Sago palms are available as bonsai trees. • Highly toxic; a single bean can kill a dog. Principal Toxin Rhododendron (Rhododendron) • The outer coating of the bean must be • Cycasin, a glycoside, yields methyla- ruptured (chewed) to release the ricin. zoxymethanol after bacteria metabolism Many species of plants from the Ericaceae Clinical Signs • Cycasin is present in the whole plant, but (heath) family, including Rhododendron • May take up to 24 hours to appear; ini- concentration is highest in the seeds; species (rhododendron, azalea, rosebay), tial signs include vomiting and often ingestion of as few as 1 to 2 seeds can Kalmia species (laurel), Leucothoe species bloody diarrhea, abdominal pain, weak- cause severe clinical signs and death. (black laurel, fetterbush), Lyonia ligustrina ness, and ataxia. Clinical Signs (maleberry, staggerbush), Pieris japonica • Hemoconcentration, leukocytosis, and • Initially, vomiting, possibly beginning (Japanese pieris), Ledum glandulosum elevated liver enzymes can be seen on within a few minutes of ingestion of the (Labrador tea) clinical laboratory testing. seeds; vomiting may last for hours. • Ornamental plant found throughout Treatment • Hypersalivation and polydipsia can be North America; size of plant and leaves • Decontamination; gastrointestinal protec- seen. varies greatly with species. tants, such as sucralfate and histamine • Over the next few days, anorexia, diar- blockers, intravenous fluids, and general rhea or constipation, hepatomegaly, and supportive care icterus are seen. 12.....march.2005.....NAVC clinician’s brief......................................................................................................................consultant on call Principal Toxin • Vomiting and neurologic signs are most FOXGLOVE • Grayanotoxins (formerly know as common in dogs, although bradycardia Three species andromedroxtoxin) can also be seen. occur in the • Toxin blocks the sodium channel in cells; Treatment United States: principally affects muscle and nerve cells. • Symptomatic care for neurologic and car- Digitalis purpurea • Whole plant is toxic. diac signs with atropine and/or lidocaine (common or pur- Clinical Signs Prognosis ple foxglove); D. • Predominately vomiting, starting within a • Guarded if signs appear lanata (Grecian few hours of ingestion; diarrhea is rare. foxglove); and D. • Aspiration pneumonia is a possible AUTUMN CROCUSES lutea (straw fox- sequela. glove). • Cardiac arrhythmias are possible. • Occurs wild in • Neurologic signs may include depression, the Pacific ataxia, weakness, and seizures. Northwest but is Common foxglove Treatment grown as an (Digitalis purpurea) Courtesy Dr. Anthony Knight. • Symptomatic and supportive care for ornamental Reprinted from A Guide to Plant Poisoning of Animals in North vomiting, arrhythmias, and seizures throughout America. Knight AP,Walter RG. Jackson, WY: Teton New Media, Prognosis North America; 2001, p 62, with permission. • Good if seizures or aspiration has not stems can range occurred from 1 to 6 feet tall with 1- to 2-inch conical flowers. Showy autumn crocus (Colchicum speciosum) YEWS Principal Toxin Colchicum autumnale (autumn crocus, • Cardenolides, principally digitalis, a car- meadow saffron); Colchicum speciosum diac glycoside (showy autumn crocus) • All parts of the plant are toxic, but high- • Occur throughout the United States; est concentrations are found in the flow- leaves, which grow from the base, can ers, fruit, and immature leaves. reach about a foot long; flowers appear • Dried plant matter retains toxicity. after the leaves have died in the autumn. Clinical Signs Principal Toxin • Initially, gastrointestinal signs are present. • Colchicine and similar alkaloids which • Cardiac arrhythmias of any type can prevent cell division occur. • All parts of the plant are toxic but high- Treatment Yew (Taxus) est concentration of the toxin is found in • Repeated doses of activated charcoal are Numerous Taxus species the flower, the corm, and the seeds. especially efficacious. • Occur throughout the United States; Clinical Signs • Supportive care for gastrointestinal signs often used as hedges; can grow up to 75 • Signs may take 12 to 24 hours to develop • Symptomatic control of arrhythmias (e.g., feet high depending on species, but often and initially occur as hypersalivation, atropine for bradycardia, lidocaine for are trimmed. depression, vomiting, milky or bloody ventricular tachycardia). Digibind (Savage Principal Toxin diarrhea, and abdominal pain. Laboratories, Melville, NY), a Fab anti- • Various taxane derivatives or taxines, • Progress to weakness, paresis, and col- body, can be used to bind and enhance which are negative inotropes and lapse. elimination of