Understanding Polyarthritis

What causes polyarthritis?

Many things can cause polyarthritis, including structural arthritis, autoimmune disease, crystal arthritis, infectious arthritis, medicine-related arthritis, and paraneoplastic syndromes (a rare complication of some cancers).

Each of these causes can be related to certain conditions.

• Structural arthritis:

  • Osteoarthritis

  • Trauma

• Autoimmune disease:

  • Rheumatoid arthritis

  • Psoriatic arthritis

  • Sjogren's syndrome

  • Reactive arthritis

  • Myositis

  • Lupus

  • Vasculitis

  • Sarcoid

• Crystal arthritis:

  • Gout

  • Pseudogout

• Infectious arthritis:

  • Bacterial infections

    • Lyme disease

    • Staph infection (staphylococcus)

    • Meningococcal infection

  • Viral infections

    • Hepatitis A, B, or C

    • HIV

    • Rubella

    • Human parvovirus B19

    • Epstein-Barr virus

• Paraneoplastic syndromes

  • Lambert-Eaton myasthenic syndrome

  • Stiff person syndrome

  • Encephalomyelitis

  • Myasthenia gravis

  • Cerebellar degeneration

  • Limbic or brainstem encephalitis

  • Neuromyotonia

  • Opsoclonus

  • Sensory neuropathy

• Medicine side effects most commonly from antithyroid medicines, antibiotics such as clindamycin, and immune checkpoint inhibitors.

Symptoms of polyarthritis

Symptoms may vary for each person, depending on the cause. They may start suddenly, or occur for a few months. Symptoms can include:

• Joint pain.

• Joint swelling.

• Warmth and redness in the affected area.

• Stiff joints.

• Decreased ability to make certain motions.

In addition to joint symptoms, some people may also have rashes, sweating, unexplained weight loss, fatigue, and fever.

Diagnosing polyarthritis

Polyarthritis can have many possible causes, so making a diagnosis can be hard. Your health care provider will ask about your health history and do a physical exam. They will check to see which joints are affected. And they will check if the joint pain is on both sides of your body or only in joints on one side. They will ask you when your symptoms started, and how severe they have been.

You may also need one or more tests such as:

• Complete blood count (CBC). This is done to look for viral infections.

• Erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) tests. These can help show if a condition is inflammatory or noninflammatory.

• Certain blood tests to look for autoimmune disease such as ANA (antinuclear antibody), RF (rheumatoid factor) and CCP (cyclic citrullinated peptide).

• Serum uric acid. High uric acid levels may mean you have gout, although some people with high uric acid don't have gout.

• Synovial fluid tests (joint aspiration). A sample of the thick fluid between your joints may be taken and checked in a lab.

• Imaging tests. An X-ray can provide a detailed look at the bones. A CT scan or MRI can help show damage to the whole joint.

Treatment for polyarthritis

The goal of treatment is to reduce inflammation and manage symptoms. Depending on what is causing the polyarthritis, your health care provider may advise you to take certain medicines. These may include:

• Acetaminophen. It can provide pain relief.

• Nonsteroidal anti-inflammatory drugs (NSAIDs). They can help ease fever and pain and reduce swelling and stiffness. They include over-the-counter medicines such as naproxen and ibuprofen, and prescription medicines.

• Antibiotics. These can help when the cause is an infection.

• Corticosteroids. These can ease pain and control inflammation. They also slow down the immune response. They may be taken by mouth (orally) or as a shot (injection).

• Disease-modifying anti-rheumatic drugs (DMARDs). These medicines help slow down the immune system response for people with certain autoimmune causes of polyarthritis.

In addition, a treatment plan may include:

• Exercise. Low-impact exercise that’s easy on the joints is helpful. This includes swimming, biking, yoga, and walking.

• Heat or cold therapy. This can help to ease pain.

• A splint or sling to keep a joint from moving. This can help ease pain.