Mountain Laurel Poisoning in Dogs

Mountain laurel is an evergreen flowering shrub which happens to be the state flower of Pennsylvania. It has a wide distribution in Pennsylvania and other eastern regions but is uncommon in northwestern areas. While this shrub is nice to look at, it is toxic to your dog if he ingests any part of it. He can develop mild toxicity symptoms related to gastrointestinal upset, or he can develop a severe reaction that may end with him in a coma. 

Grayanotoxin is the harmful substance found within this shrub. If you believe your pet consumed part of the mountain laurel and is acting ill, or if you witnessed your dog chewing on or eating this foliage, contact your veterinarian as soon as possible as symptoms can become serious.

The mountain laurel is a native shrub in eastern North America. If your dog ingests a part of this plant, he may develop symptoms of toxicity. If you witness your dog ingesting this plant, you should contact your veterinarian immediately.

Symptoms of mountain laurel poisoning will vary depending on the amount your dog ingested. Symptoms of toxicity include

• Excessive drooling
• Loss of appetite
• Vomiting
• Muscular spasms
• Tremors
• Ataxia
• Weakness
• Pinpoint pupils
• Diarrhea
• Arrhythmias
• Paralysis 
• Coma
• Death

Symptoms typically develop a few hours after ingestion.

Types

The mountain laurel belongs to the Ericaceae family and the genus Kalmia. There are many different species of the mountain laurel plant with Kalmia latifolia being the most common one. The mountain laurel is usually found along water, forest edges, or meadows with favorable soil. It produces pink or white dish shaped flowers making it aesthetically pleasing.

Grayanotoxin is the toxic substance found in the mountain laurel. Grayanotoxin interferes with the body’s sodium channels by binding to them in certain places. This inappropriate binding prevents sodium channel inactivation which leads to cell depolarization. When abnormal cell hyperpolarization occurs, is causes the body systems to malfunction resulting in continuous increased vagal tone.

When you first arrive at the veterinarian’s office, she will begin by performing a physical exam. This will allow her to properly assess the symptoms your dog is experiencing and note any abnormalities of his vitals. If your dog vomits while at the veterinarian’s office, she will examine the contents for any clues as to what he ingested. If he is having diarrhea, she may perform a fecal analysis to rule out any type of internal parasite or bacterial overgrowth. 

Additional laboratory work will be conducted to assess how your dog’s body is handling the toxin. A urinalysis may be performed to assess kidney function. Blood work will consist of a complete blood count (CBC), chemistry panel, and packed cell volume (PCV). The CBC and chemistry panel will provide a baseline of how each organ is metabolizing the toxin. The PCV will determine the hydration status of your dog. 

If your dog is experiencing some type of arrhythmia, the veterinarian may take radiographs to see how the heart looks. She may also perform an ECG or ultrasound to find where the abnormal beat is occurring. With proper diagnosis of where the arrhythmia is occurring, she will be able to administer the proper medication to correct it.

If you believe your dog ingested the mountain laurel plant, take a piece with you to the veterinarian’s office. This will allow for proper identification of the plant and the toxin it contains. With correct identification, she will be able to treat the toxicity quickly and effectively.

The toxicity symptoms of mountain laurel poisoning your dog is experiencing will determine his course of treatment. If your dog is vomiting and having excessive diarrhea episodes, fluid therapy with electrolytes will be administered to correct any dehydration and to prevent it from becoming more severe. The fluids will also flush the toxin from his body quicker. 

If your dog is not vomiting, the veterinarian may attempt to induce vomiting to rid the stomach of any remaining plant particles. If this is unsuccessful, she may administer activated charcoal to bind with and absorb any remaining toxin in your dog’s body. She may also administer a laxative to make the plant material pass through his system quicker.

If your dog is experiencing any type of muscular spasms, paralysis, weakness, ataxia, or any other similar issue, the veterinarian will move him to a quiet, confined area to keep him as calm as possible. Additional medications, such as a nerve stimulant, may be administered. If your dog is experiencing arrhythmias, the veterinarian may hook him up to monitoring equipment for a continuous reading of his heart function. Supportive heart medication may be administered if your veterinarian thinks it is needed.

Toxicity from mountain laurel poisoning may be considered mild to severe depending on the amount your dog ingests. If your dog is only suffering gastrointestinal upset, prognosis for a full recovery is good. If your dog is suffering more severe symptoms related to the heart or central nervous system, prognosis of a full recovery declines. 

If you receive veterinary care for your dog as soon as possible, he is likely to avoid development of long term health problems. The best thing you can do is prevent your dog from ingesting any amount of the mountain laurel plant. If you purposefully planted this shrub in your garden or around your house, keep it in an area your dog does not have access to. If you are out on a walk, do not let him chew on or eat unfamiliar foliage.