by Teresa Garden, DVM
This has been the most wondrous and enjoyable St. Louis spring in many years. Days have been sunny and warm; nights cool. Due to this great weather our plants and flowers have showered us with a dazzling array of beauty and lushness. And while their beauty can be breath-taking, some plants and flowers may have an uglier side to them with regards to our pets. Many house and garden plants contain chemicals that, if ingested in sufficient quantities can produce toxic effects in animals.
Plant poisonings are not diagnosed often in veterinary practice. However, there are conditions conducive to plant poisonings. Puppies and kittens are predisposed due to their curious nature and willingness to put anything into their mouths. Boredom can lead to chewing on and possibly ingesting the wrong plant. A change in a pet’s surroundings increases the odds of plant ingestion. New plants in the house can peak a pet’s interest. Mistletoe and poinsettias make their appearance during the rushed and stressful holiday season. New homes, new babies, owner illness, and vacations are great times for dogs and cats to start foraging because they may not be getting enough attention. Chewing on a plant is not the same as ingesting the plant. Illness or toxicity can only result if a poisonous plant is consumed.
Diagnosis of and treatment for a plant poisoning can only be made if the plant is identified by the pet guardian. The amount consumed is important. (Usually a single bite will not be of any consequence with the exception of deadly plants such as oleander or castor bean.) Diagnosis of a plant poisoning cannot be made on clinical symptoms alone since the symptoms are vague and common to many disease processes. Therefore, diagnosis can only be made if there are symptoms plus confirmation of ingestion plus plant identification. Treatment of plant poisonings is supportive; rarely are there specific antidotes. The first goal is to remove any plant material from the digestive tract as soon as possible. Hydrogen peroxide can be given orally to induce vomiting within 2 hours of ingestion. Gastric lavage under sedation can be performed by your vet or local animal emergency center to wash out stomach contents.
Treatment rationales are based upon clinical symptoms. GI symptoms such as vomiting drooling, anorexia, or diarrhea are treated with GI protectants such as pepcid and sucralfate, antiemetics, and IV fluids. Nerve toxicity symptoms such as tremors, seizures, ataxia, weakness can be treated with tranquilizers or sedatives and IV fluids. Kidney or liver damage can be diagnosed by blood tests and treated with IV fluids, medications, and in some cases blood transfusions.
There are literally hundreds of plants which may be toxic to our pets. One of the most common dangers to cats is the lily plant. All parts of the lily plant including pollen are toxic to cats. Ingestion can cause kidney damage, vomiting or lethargy within 2 hours. The cat may appear to recover, only to deteriorate 24-72 hours later. Renal failure and death can follow within 3-6 days. Prompt, aggressive therapy can be successful if instituted within 18 hours of ingestion. Lilys can be both an indoor and outdoor danger to cats. Grapes and raisins can also be nephrotoxic to both dogs and cats. Other nephrotoxic plants include the day-lily, rhubarb, shamrock, and wood sorrel.
Many of the over 3,000 species of mushrooms and toadstools are toxic to man and companion animals. Amanita, also known as “Death Cap” or “Death Cup” is a well known poisonous mushroom. They tend to grow in gardens, lawns, and wooded areas. Amanita are bland in taste so pets are not deterred from eating them. This mushroom when ingested can cause GI irritation or more severe and life-threatening conditions like nerve poisoning or liver failure. Liver damage can also result from ingestion of any part of the Sago palm. This plant can cause bloody diarrhea, ataxia, seizure, coma, jaundice, and death. Prompt treatment is necessary for survival, but liver damage can be long-term.
Ingestion of macadamia nuts, china berry, or bleeding-hearts can result in central nervous system toxicity presenting as tremors, seizure, weakness, ataxia, or even death. Other plants with potential CNS toxicity include: castor bean, belladonna, jimsonweed, nightshade, daffodil, holly, and ivy. Chewed pits from plums, peaches, cherries, and apricots can release cyanide and cause labored breathing, poor circulation, weakness, seizure, coma, and death. Avocado ingestion by rabbits or birds can lead to cardiac arrhythmias, pulmonary edema, dyspnea, and death. The pit can cause a foreign body obstruction in dogs. Ingestion of hulls from English or Black walnuts can result in gastroenteritis or convulsions.
Cardiotoxic plants include rhododendrons, azaleas, yews, foxglove, oleander, and lily-of-the-valley. Onions, chives, and garlic can damage red blood cells. Many popular plants can cause mild GI irritation if ingested: poinsettia, aloe, crocus, gladiola, hyacinth, iris, buttercup, dumb cane, and philodendron, and elephant ear.
Plant poisoning in small animals is usually accidental. Accidents can be prevented by understanding the conditions under which poisoning may occur and then taking steps to prevent occurrence. Authenticated reports of plant poisonings in dogs and cats are rare. The true occurrence of how often our pets are sick because of plant ingestion eludes us. We are not always there to be an eye-witness to plant ingestion. If you happen to be present when BoBo starts to graze then remember: When in doubt, spit it out!
Dr. Teresa Garden is chief veterinarian/owner of Animal Health & Healing, a full-service holistic and conventional veterinary practice in the Maplewood/Richmond Heights area. AnimalHealthandHealiing.com; phone: 314-781-1738.