What is amyloidosis?
Amyloidosis occurs when proteins called "amyloid" are deposited outside cells in various tissues and organs, such as the kidneys and liver, which causes tissue damage and organ dysfunction. It is an uncommon condition in dogs.
While certain family lines of beagles, as well as Chinese Shar-Peis, collies, treeing walker coonhounds, and English foxhounds seem to be predisposed, there is no clear genetic profile in many of these breeds. Most dogs diagnosed with amyloidosis are older than 5 years of age, although the age range at diagnosis can be from 1 to 15 years of age. Chinese Shar-Peis are often diagnosed at a younger age. It appears that the risk for developing amyloidosis increases with age.
What are the signs of amyloidosis?
The signs of amyloidosis depend on the organ system that is affected, but kidney involvement is most common. Affected dogs may have appetite loss, lethargy, increased thirst and urination, weight loss, vomiting, and diarrhea. In some cases, fluid builds up under the skin, in the abdomen (belly), and/or in the chest cavity. If the disease progresses, the dog may develop signs specific to kidney failure including:
- mouth ulcers
- extreme weight loss
- ongoing vomiting
- dehydration
Up to 40% of affected dogs develop blood clots in their blood vessels and, depending on the location, there may be clinical signs such as difficulty breathing or weakness in a rear leg.
For dogs with liver amyloidosis, signs may include weakness, pale gum color, distended abdomen, rapid heart rate, rapid breathing, abdominal pain, and collapse. This is due to bleeding from the liver.
What causes amyloidosis?
There must be a family predisposition for amyloid to be deposited in the tissues, but it can be triggered by chronic infection, chronic inflammation, and certain types of cancer.
How is amyloidosis diagnosed?
A diagnosis of amyloidosis is often based on clinical signs associated with the affected organs. Blood testing and examination of the urine will often show abnormalities as the disease progresses. However, biopsy of the affected organs (kidneys/liver) is required for a definitive diagnosis.
Is there any treatment for amyloidosis?
If the dog with amyloidosis develops kidney failure, hospitalization with IV fluids may provide a way to stabilize the condition. Once stabilized, the dog may be able to tolerate outpatient management focused on kidney support with appropriate nutrition and medication. Some dogs with amyloidosis also develop hypertension (high blood pressure) that should be treated. Any underlying condition like cancer, infection, or inflammation should be treated if possible.
Affected Shar-Pei dogs have sometimes been treated with the drug colchicine (brand names Colcrys®, Mitigare®, Gloperba®) to reduce the harmful effects of amyloid deposition. This drug, however, must be used carefully due to the potential to interact with other drugs.
Ongoing monitoring of organ system function, fluid balance, and blood pressure is important in dogs with amyloidosis. Any emerging symptoms can then be treated as soon as they are identified. Amyloidosis is a devastating disease, and if the kidneys are affected, the prognosis varies from 3 to 20 months.
