Polyarthritis

Polyarthritis refers to an inflammation of multiple joints and occurs in dogs for various reasons. The condition often manifests as pain, stiffness and movement disorders. Possible triggers include autoimmune reactions, infections or being a concomitant feature of other diseases. The earlier the diagnosis is made and treatment initiated, the better the dog’s quality of life can be maintained.

Causes of polyarthritis in dogs

The causes of polyarthritis can be divided into two main categories: non-erosive and erosive forms.

Non-erosive polyarthritis:

• This form is the most common in dogs and leads to inflammation of the joints without destroying the joint structures themselves. Causes include:
• Autoimmune diseases: The immune system mistakenly attacks its own joint tissue, triggering an inflammatory reaction. An example is idiopathic polyarthritis, where the exact cause remains unknown.
• Infections: Bacterial, viral or parasitic infections can overstimulate the immune response and trigger a reactive polyarthritis. Known triggers are Lyme disease (Lyme borreliosis) and Ehrlichiosis.
• Vaccine reactions: In rare cases, an overreaction to vaccines or medications can also trigger polyarthritis.

Erosive polyarthritis:

• This rarer form leads to the destruction of joint cartilage and bone. An example is rheumatoid arthritis, where the immune system attacks and damages joint tissue.

Symptoms of polyarthritis in dogs

The symptoms of polyarthritis vary depending on the severity of the inflammation and the joints affected. The most common signs include:

1. Lameness: Dogs often show shifting lameness, which affects multiple limbs. The severity can fluctuate significantly from one day to the next.
2. Pain and stiffness: Especially after getting up or after periods of rest, the affected joints often feel stiff. The dog has difficulty moving or standing up.
3. Swelling: The joints can be swollen, warm and painful to the touch, a direct sign of the inflammatory reaction in the joint.
4. Fever: In some cases, polyarthritis is accompanied by fever, especially if there is a systemic infection or autoimmune disease.
5. Reduced appetite and lethargy: Persistent pain and discomfort often lead to loss of appetite and lethargy. The dog appears weak and less active.
6. Movement restrictions: In severe cases, polyarthritis severely restricts the mobility of the joints, so that the dog can only walk or stand with difficulty.

Diagnosis of polyarthritis in dogs

The diagnosis requires a comprehensive veterinary examination to determine the cause of the disease. The following methods are used:

1. Clinical examination: The vet examines the affected joints for swelling, pain sensitivity and mobility and assesses the dog’s general health status.
2. Blood tests: Blood tests provide clues about inflammations in the body. Elevated levels of white blood cells and inflammatory markers (e.g. C-reactive protein) can indicate polyarthritis. Specific tests for autoantibodies (e.g. rheumatoid factor) are helpful if rheumatoid arthritis is suspected.
3. X-rays: X-ray images of the affected joints show structural changes such as swelling, cartilage damage or bone erosions. This is particularly useful for distinguishing non-erosive from erosive polyarthritis.
4. Joint fluid analysis: A joint fluid tap (arthrocentesis) allows the fluid in the joints to be withdrawn and analysed. The examination can reveal inflammatory cells or signs of infection.
5. Specific infection tests: If an infectious cause is suspected, tests for Lyme disease, Ehrlichiosis or other infections are carried out.

Treatment of polyarthritis in dogs

Treatment depends on the cause and severity of the disease. The focus is on controlling inflammation, relieving pain and improving joint mobility. Common approaches include:

1. Anti-inflammatory medications: Non-steroidal anti-inflammatory drugs (NSAIDs) such as carprofen, meloxicam or firocoxib are frequently used to relieve inflammation and pain. They are generally well tolerated and help control symptoms.
2. Immunomodulatory medications: In cases of autoimmune polyarthritis, immunosuppressants such as prednisolone (a corticosteroid) or cyclosporine are often used to dampen the immune system and reduce joint inflammation.
3. Antibiotics: If there is an infectious cause, such as Lyme disease or Ehrlichiosis, antibiotics are prescribed to treat the infection.
4. Painkillers: In addition to anti-inflammatory preparations, painkillers such as gabapentin or tramadol can be administered to control pain.
5. Dietary adjustment and supplementation: A balanced diet and supplements such as glucosamine, chondroitin and omega-3 fatty acids can support joint health and positively influence the course of polyarthritis.
6. Physiotherapy: Physiotherapy and hydrotherapy can improve joint mobility and strengthen muscles. Regular, gentle exercise helps to reduce stiffness.
7. Weight control: A healthy body weight noticeably relieves the joints; overweight worsens symptoms and should be consistently avoided.
8. Alternative therapies: In some cases, acupuncture, laser therapy or chiropractic treatment can contribute to pain relief and an improvement in quality of life.

Prognosis

The prognosis depends on the cause and severity of the disease:

• Non-erosive polyarthritis can often be controlled well, especially if treatment is started early. With well-adjusted medication and an adapted lifestyle, affected dogs can live comfortably.
• Erosive polyarthritis, such as rheumatoid arthritis, is more difficult to treat because it causes irreversible damage to the joints. In these cases, therapy aims to slow the progression of the disease and alleviate symptoms.