What is Yew Poisoning?
The yew is a common evergreen tree that is toxic to all animals including cats. Grown for its ornamental qualities, it is from the plant family Taxaceae and common names include Japanese yew, Chinese yew, and English yew. All parts of the plant, except the seed covering, are toxic including evergreen foliage and succulent red berries which contain taxine, an extremely toxic plant compound to cats and other animals. If ingested, muscle tremors, seizures, respiratory distress, and cardiac failure resulting in death can occur.
Symptoms of Yew Poisoning in Cats
Symptoms of yew poisoning in cats occur suddenly and progress rapidly. They include:
- Drooling and vomiting
- Weakness, muscle tremors
- Respiratory distress, rapid breathing
- Changes in heart rate and blood pressure
- Dilated pupils
Symptoms usually occur rapidly but cases have been reported of symptoms occurring in some animals up to several days after ingestion.
Causes of Yew Poisoning in Cats
All plant parts except the seed covering (aril), which is favored as a food source by some birds, are poisonous. Various toxins are present, but the main toxic compound present in the yew plant is cardiotoxic taxine alkaloids. The concentrations of this toxic compound are higher in the winter. Your cat may come into contact with a yew tree outdoors or indoors where yew tree foliage may be dried and used for decorations such as wreaths. Even when dried, the yew tree material is toxic and dried plant parts that fall off of household decor may be used as playthings or sampled by your cat and present an extreme hazard. A small dose can be lethal to your cat, as taxine is very toxic and cats are very small animals, requiring a relatively small amount of the plant to be fatal.
Diagnosis of Yew Poisoning in Cats
If your suspect your cat has ingested yew plant in the yard or in your home, bring a sample of the plant to the veterinarian with you to confirm its identity. Due to the extreme danger from yew ingestion, your veterinarian may proceed with treatment immediately if yew poisoning is suspected. Diagnosis will be based on the presence of yew tree material and symptoms of poisoning. Your cat’s vital signs will be monitored to determine the extent of toxic symptoms and determine appropriate treatment. Your veterinarian will want to know how recently the yew plant was ingested to determine if steps to purge the plant from your cat's system will be effective. Tests such as blood and urine and radiography to rule out other conditions may be performed. These tests may also be used to determine the extent of damage and disorder affecting your cat.
Treatment of Yew Poisoning in Cats
As poisoning by yew tree progresses rapidly and death results quickly after ingestion, the opportunity for successful treatment is not always available. If caught early, inducing emesis (vomiting) by 3% hydrogen peroxide solutions or xylazine administered by a veterinarian will help to remove as much of the plant from your cat's stomach contents as possible. Gastric lavage is also a possible option to remove plant material from your pet's stomach. Activated charcoal may be administered to bind with yew plant compounds in the gut and pass them through the gastrointestinal system with minimal absorption. Your veterinarian may administer Atropine sulfate to attempt to counteract cardiac arrhythmia. Additional supportive treatment such as intravenous fluid therapy to control blood pressure and ventilation for respiratory distress may be attempted. Medications to control seizures and other neurological symptoms may also be provided.
Recovery of Yew Poisoning in Cats
Unfortunately, poisoning by a yew plant is usually severe in cats and other animals and little opportunity for intervention that would affect recovery may be available. If your cat is treated quickly and aggressively and recovers from yew poisoning they will require careful monitoring and supportive care for several days to ensure recovery. If symptoms of organ damage occur, this will need to be addressed by a veterinarian. Your cat will need to be kept in a warm quiet place and allowed to recover with water and small amounts of appropriate food provided. Intravenous fluids may be necessary, along with other medications to address symptoms during recovery. Continuous monitoring by your veterinarian and follow up to ensure recovery will be required. Limiting your cat’s access to yew plants outside and keeping household decor with yew tree foliage out of your home will help prevent poisoning.