Let’s pretend you are having a conversation with a friend and she says she had an embolism. This medical term refers to a foreign body like a blood clot, fat or air bubble that breaks free and then blocks the blood circulation beyond it.
More often than not, you would assume that it probably started in her leg and that it traveled up to her lungs. Embolism is actually a generic term like a broken bone. The question then is where did it cause a problem and where did it originate?
In dogs, there are two distinct and clinically recognized major embolisms: pulmonary thromboembolism (PTE) and fibrocartilaginous embolism (FCE).
Pulmonary Thromboembolism (PTE)
Most of us would think of PTE in terms of a traditional embolism – a blood clot becomes stuck in one of the arteries that is likely narrowed due to arthrosclerosis and that feeds into the lungs, thereby blocking and causing slower flowing blood to the lungs (pulmonary tree).
It can originate in many of the major veins in the body or in the right atrium of the heart. In dogs, an underlying condition usually is the cause or contributor; these include: Cushing’s disease (overactive adrenal function), pancreatitis, kidney disease, microbial infections, hypothyroidism, intestinal disease, heartworm disease, cardiac disease, sepsis, endotoxins, immune-mediated hemolytic anemia and certain cancers.
Diagnosing PTE is often difficult because results mimic other diseases. Remember, too, that PTE is often the result of another disease.
Signs include labored breathing, coughing, coughing up blood, blue-tinged gums, collapse, shock and sudden death. Of course, signs vary based on the amount of lung and heart damage that has already occurred.
Oftentimes, like in people, dogs are prescribed anticoagulants and antiplatelet drugs to help prevent the overactive blood clotting.
Fibrocartilaginous Embolism (FCE)
Fibrocartilage is whitish, fibrous connective tissue that is a part of the cushiony material between the discs of the spinal column. For some reason, it can become dislodged and travel into the bloodstream and block arteries.
While we do not know exactly how this is happening, we do have some clues. We know that it typically occurs in large and giant breeds between 3-5 years of age, and after heavy exercise. Typically is not always the case, of course. Evidence has shown that it can happen in even younger or older dogs, in smaller breeds such as Shetland Sheepdogs and Yorkies, and in dogs that were simply walking.
At this point in time, it is considered an acute condition with no known linkage to genetics or underlying disease.
Signs are a sudden yelping of pain, followed by weakness or paralysis generally on one side of the body and possible inability to control bladder and bowel movements.
Even though physical activity has been observed or linked to causing FCE, we still employ physical therapy to resolve the issue and to help the companion dog regain mobility. In fact, one retrospective analysis demonstrated that a more positive outcome usually ensues, the faster FCE is diagnosed and a physiotherapy regime is implemented.
Most physiotherapy protocols include a variety of treatments such as water therapy, electrostimulation, assisted walking, and passive range of motion (PROM) exercises. PROM exercises involve assistance from a caregiver moving the companion dog’s limbs. Depending on the severity of the FCE and treatment protocol, recovery can take as little as two weeks or up to six weeks.
Gandini, G et al. “Fibrocartilaginous embolism in 75 dogs: clinical findings and factors influencing the recovery rate.” The Journal of small animal practice vol. 44,2 (2003): 76-80. doi:10.1111/j.1748-5827.2003.tb00124.x, https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1748-5827.2003.tb00124.x.
Spinella, Giuseppe et al. “Overview of the Current Literature on the Most Common Neurological Diseases in Dogs with a Particular Focus on Rehabilitation.” Veterinary sciences vol. 9,8 429. 13 Aug. 2022, doi:10.3390/vetsci9080429, https://www.mdpi.com/2306-7381/9/8/429.
Tonozzi, Caroline C. Pulmonary Thromboembolism in Dogs and Cats. Merck Veterinary Manual, Oct. 2022, https://www.merckvetmanual.com/veterinary/respiratory-system/respiratory-diseases-of-small-animals/pulmonary-thromboembolism-in-dogs-and-cats#v3295032.