Pannus is an abnormal growth of tissue that develops in the joints. It can form in the later stages of rheumatoid arthritis.

Rheumatoid arthritis (RA) is an autoimmune disease that causes chronic inflammation in the joints. When a person has RA, the synovium, which is the protective lining of the joints, grows much thicker. This abnormal tissue growth is pannus.

In this article, we look at the link between pannus and RA. We also discuss the treatments, complications, and outlook.

Share on Pinterest
Cavan Images/Getty Images

Pannus is abnormal tissue growth and can occur throughout the body, including the joints, eye cornea, and abdomen.

When someone has RA, their immune system contributes to hyperplasia of the synovium, activation of immune cells, and release of proteins called cytokines and chemokines. This pro-inflammatory microenvironment triggers new blood vessels to develop, promoting the further growth of extra tissue. This tissue thickens as it grows, and eventually, pannus forms in the joint.

As the pannus develops, it takes up more space in the affected joint. Small, hair-like growths called villi also develop on the pannus, making its surface rough and uneven.

Pannus may cause the joint to produce excess fluid, which can be harmful.

Normal synovium produces small amounts of fluids to lubricate the joint. The fluid also helps to reduce friction and protect the joint from impact damage.

In joint inflammation, this fluid can contain harmful enzymes, acids, and proteins that can damage bone and cartilage. The pannus may be painful, and can lead to permanent damage and reduced mobility in the joint.

RA results from an overactive immune system that mistakenly attacks its own tissue, leading to pannus formation.

Currently, there is no procedure to reverse rheumatoid arthritis and pannus, but treatments can help manage symptoms and slow down or stop the condition’s progress.

The American College of Rheumatology recommends disease-modifying anti-rheumatic drugs (DMARDs) for treating rheumatoid arthritis. These medications help suppress the immune system and, as a result, may reduce swelling and slow the development of the pannus.

A patient may need to take DMARDs until they achieve clinical remission.

Non-steroidal anti-inflammatory drugs (NSAIDs) may also assist in the management of rheumatoid arthritis. These medications can reduce inflammation, swelling, and joint stiffness.

Physical therapy can also help with RA symptoms. Regular stretches and exercise can help keep a person’s joints healthy and improve mobility.

In severe cases, a doctor may recommend surgery to remove, replace, or fuse bones together to prevent further damage and reduce pain in a damaged joint. A doctor will usually only advocate surgery in latter-stage rheumatoid arthritis, when all non-surgical treatments have failed to halt the condition’s progression.

The growth of pannus in people with RA can cause lasting damage to the joint, bone, and tissue. This can lead to severe pain, joint stiffness, and mobility issues.

Along with pannus, RA can cause the following symptoms:

People with RA may also experience more extensive complications. The risk of these complications increases with age as the disease progresses. According to the Centers for Disease Control and Prevention, the highest rate of RA is in people over 60 years old.

People with RA are at an increased risk of:

In the earlier stage of arthritis, medication can slow down the growth of a pannus. People may still experience symptoms, such as inflammation and joint pain, but the joint can remain functional and damage inhibited.

Over time, pannus can grow and become a more severe problem. It can cause pain, swelling, and stiffness in the joint. This can affect joint mobility and potentially cause permanent damage.

Treatments and outlook for people with RA have improved significantly. Medications can help people manage their symptoms and reduce or stop the progression of the condition.