Scotch Broom Poisoning in Dogs

The Cytisus scoparius, better known as the Scotch broom or the common broom, is a perennial shrub native to western and central Europe. Initially, the Scotch broom was imported into North America as an ornamental shrub, due to its eye-catching yellow flowers. It has flourished in this new environment and now is considered an invasive species in several states, as well as in portions of western Canada. This plant contains moderate concentrations of the alkaloids cytisine and sparteine which can have an adverse effect on the central nervous system and circulatory system when absorbed into the blood. If you suspect your pet has consumed part of the Scotch broom plant, take a sample of the plant if possible, and contact your veterinarian for further instructions.

The Scotch broom (Cytisus scoparius), is an invasive shrub with striking yellow flowers. This plant contains toxic alkaloids that can have an adverse effect on your pet's heart and central nervous system.

The severity of the signs of intoxication from ingesting Scotch broom will be dependent on the amount consumed, and the size and sensitivity of the patient. The symptoms may be displayed could include:

• Abdominal discomfort
• Diarrhea
• Incoordination
• Increased heart rate
• Lethargy
• Loss of appetite
• Nausea
• Numbness
• Vomiting
• Weakness

Munching on this plant may also induce contractions in pregnant individuals. 

Types

If you witness your companion chewing on or eating a plant that you think is Scotch broom, it may be a good idea to get a sample of the plant to assist in identification. Two common plants that grow in the same regions that are frequently confused with Scotch broom are:

Common Gorse (Ulex europaeus)- This plant looks similar visually, although close inspection will reveal the addition of numerous thorns along its branches. Its branches and fruit are toxic, but the symptoms are indicative of a toxin that affects the central nervous system rather than the cardiovascular system. 

Spanish Broom (Spartium junceum)- This plant is nearly identical to Scotch broom in many ways, including the production of the same poison alkaloids. The concentration levels of sparteine in the Spanish variety are higher than in Scotch broom and can quickly cause a dangerous drop in blood pressure.

The threat that is posed by the Cytisus scoparius plant, better known as Scotch broom, is two-fold. The most toxic compounds in the Scotch broom are alkaloids by the names of sparteine and cytisine. Cytisine is closely related to nicotine and is sometimes used to assist as a smoking cessation treatment. When a substantial amount of cytisine is absorbed into the system, it can lead to vomiting, convulsions, chest pain and in severe circumstances, death. Sparteine is a 1a antiarrhythmic, which means that it interferes with the natural rhythm of the heart by functioning as a sodium channel blocker. It is produced in the Scotch broom plant and the Spanish broom as well as some varieties of lupine.

If you see your pet consuming the Scotch broom, proper identification of the plant is often sufficient enough information for a preliminary diagnosis. If your canine ate what you believe to be a Scotch broom shrub, but you are uncertain of the identification you may wish to take your pet, as well as a sample of any remaining plant material, to a veterinary clinic. This will ensure a speedier identification which can help guide treatment choices. 

If the ingestion of the plant was not witnessed, your veterinarian will take particular note of any opportunistic eating that was observed or suspected in addition to any concurrent prescriptions or supplements that your dog is taking in an attempt to rule out other toxins or drug interactions. A urinalysis, biochemistry profile, and complete blood count (CBC) are likely to be requisitioned at this time, as will tests to check the functionality of the heart. Plant material discovered in the vomit or stool may help to confirm the diagnosis.

Preliminary treatment will generally be determined by how long it has been since plant material was ingested and what symptoms are presenting. If the broom plant was consumed recently, usually within an hour or two, vomiting will most likely be induced to prevent the absorption of the cytisine and sparteine into the bloodstream. Activated charcoal will then be will be dispensed to the patient in an attempt to soak up as much of the alkaloids as is possible. In situations in which substantial quantities have been ingested, your veterinarian may choose to perform a gastric irrigation under general anesthetic to remove as much toxic material from the patient’s stomach as possible. Additional supportive treatment will likely include IV fluids for dehydration as well as mixtures of electrolytes and sugars to adjust for any imbalances. The heart may need to be carefully monitored until the toxins have fully cleared the system.

Ensuring that a quiet, calm setting is available for the recuperating patient to return home to will help speed recovery. This is especially important with toxins that affect the heart as all attempts should be made to avoid further stress on the heart until the dog has had time to recover fully. Ample food and fresh water should be made available to your pet at all times. Patients that are recovering from anesthesia given for a gastric irrigation may have coordination difficulties at first, and are often initially confused and disoriented. Isolation from other pets and from children is generally advised until the medication has fully cleared your companion’s system.