Does Rheumatoid Arthritis Cause Granuloma?

A granuloma is a collection of immune cells formed in response to inflammation. Rheumatoid arthritis (RA) is a chronic autoimmune inflammatory disease. This means that the immune system in a person with RA attacks the body’s tissues. This immune attack triggers considerable inflammation, which results in the recruitment of inflammatory cells in the body. These inflammatory cells form clumps with areas of dead tissue (necrosis), which leads to granuloma formation.

Symptoms of rheumatoid granuloma may depend on its site. The granulomas under the skin are easier to identify than those affecting internal organs.

• Subcutaneous nodules appear small (2 mm to 5 cm in size), round to oval skin-colored bumps under the skin (subcutaneous).
• They are typically painless and movable although they may get fixed to the underlying structures in some cases.
• They are generally not a cause for concern; however, they may interfere with function or become painful due to repeated trauma or compression of nerves in their vicinity. 
• Repeated trauma may also make them prone to ulceration and consequent infection, which may spread through the blood to other sites as well.

Rheumatoid granulomas in internal organs may cause symptoms related to the affected organ.

• Those in the lungs may cause difficulty breathing, coughing, chest pain, or pressure 
• Cardiac granulomas generally do not cause symptoms; however, they may cause abnormal heart rhythm if the conduction system of the heart is affected. They may also result in loss of consciousness and even death in some cases.
• Granulomas in the pancreas may result in problems with digestion, abdominal pain, and weight loss.

A person can be diagnosed with rheumatoid granuloma based on the following:

• Medical history
  • The history of being diagnosed with rheumatoid arthritis (RA)
  • Joint symptoms such as arthritis of small joints, symmetrical arthritis, and morning stiffness
  • Other symptoms such as cough, chest pain, weight loss, or fever 
  • Family history of RA or other autoimmune diseases
• Physical examination to look for joint inflammation or deformity and subcutaneous nodules. Other relevant diagnostic approaches include examination of the joints, chest, and abdomen
• Investigations such as:
  • Blood tests including tests for autoantibodies in the blood (such as rheumatoid factor and anti-cyclic citrullinated peptide antibody), inflammatory markers (such as erythrocyte sedimentation rate and C-reactive protein), liver involvement (liver function tests), and kidney involvement (kidney function tests)
  • Imaging studies such as X-ray, ultrasound, endoscopic ultrasound, CT scan, and MRI
  • Other tests such as ECG to look for heart involvement and pulmonary function tests to assess lung involvement
  • Biopsy to remove a small piece of tissue from the lesion and examine it under a microscope

Rheumatoid granulomas may not require any specific treatment. For example, subcutaneous nodules that do not cause any limitation of function, pain, or discomfort may be left as such. 

Treatment options for rheumatoid arthritis (RA), such as corticosteroids, disease-modifying antirheumatic drugs, and biological agents, may help limit the disease and granuloma formation. If a certain drug used for RA treatment (such as methotrexate) causes nodule formation, the doctor may suggest an alternative.

Painful subcutaneous nodules may require local injections with steroids or numbing agents (local anesthetics). Some may need to be surgically removed. 

Visceral nodules, which affect the internal organs, may be surgically removed if they cause any problems or have a risk of complications. Surgical removal may also help diagnose the cause of granuloma. Lung (pulmonary) nodules are usually surgically removed as they carry a risk of lung complications such as scarring, pleural effusion, or small airway obstruction. Cardiac nodules may be surgically removed if they cause abnormal heart function or rhythm or blood vessel blockage (embolism).