Connection Between Rheumatoid Arthritis and Sjögren’s Syndrome

Rheumatoid arthritis (RA) and Sjögren’s syndrome are both chronic autoimmune diseases. This means that the immune system, which normally protects the body from infections, mistakenly attacks its own tissues. Sjögren’s syndrome mainly causes dryness in the mouth and eyes, while rheumatoid arthritis leads to joint inflammation and pain. These two conditions are closely related and often occur together. This article will explore the connection between rheumatoid arthritis and Sjögren’s syndrome, as well as their symptoms, diagnosis, and treatment.

1. What Are Rheumatoid Arthritis and Sjögren’s Syndrome?

Rheumatoid Arthritis (RA) is an autoimmune disease that causes pain, inflammation, and swelling in the joints. If left untreated, the inflammation can damage the joints over time, leading to loss of function. RA can also affect other parts of the body, such as the heart and lungs.

Sjögren’s Syndrome is another autoimmune disease where the immune system attacks the salivary and tear glands, leading to dryness in the mouth and eyes. Sjögren’s syndrome can occur on its own or alongside other autoimmune diseases, such as rheumatoid arthritis or lupus.

2. What Do Rheumatoid Arthritis and Sjögren’s Syndrome Have in Common?

RA and Sjögren’s syndrome have several similarities, especially in how they affect the immune system and in some of their symptoms.

• Immune System Dysregulation: In both diseases, the immune system becomes overactive and mistakenly attacks healthy cells. RA primarily attacks the synovial lining of the joints, while Sjögren’s syndrome targets the salivary and tear glands. Despite the different targets, the underlying mechanism is similar, involving an overactive immune response.
• Autoantibodies: People with these diseases often produce specific antibodies, such as antinuclear antibodies (ANA) and anti-SS-A and anti-SS-B antibodies. These antibodies attack the body’s own tissues, making the diseases worse. Many people with Sjögren’s syndrome or rheumatoid arthritis also have elevated levels of rheumatoid factor (RF), which indicates a problem with the immune system.
• Similar Symptoms: Many people with Sjögren’s syndrome also experience joint pain and inflammation. Likewise, many people with rheumatoid arthritis may have dry eyes and dry mouth, which are characteristic of Sjögren’s syndrome.

3. How Do These Diseases Develop?

Although the causes of RA and Sjögren’s syndrome are different, they share many similarities. Some of the key factors include genetics, environmental triggers, and immune system abnormalities.

• Genetic Factors: Certain genes, such as the HLA-DR gene, can increase the risk of developing these diseases. If someone in your family has these conditions, your own risk may also be higher.
• Immune System Response: In both conditions, immune cells like T cells and B cells become overactive and produce too many antibodies, which then attack the body’s healthy tissues.
• Environmental Factors: Environmental factors, such as viral infections, smoking, and chronic stress, can act as triggers that lead to the development of these autoimmune diseases.

4. How Are These Diseases Diagnosed?

Because RA and Sjögren’s syndrome are closely connected, doctors need to be careful when diagnosing them to differentiate between their symptoms.

• Blood Tests: Doctors check for the presence of autoantibodies in the blood, such as anti-SS-A, anti-SS-B, or rheumatoid factor (RF). These antibodies help in diagnosing the conditions. However, it’s important to note that some patients may have normal blood test results but still experience symptoms. This is common in autoimmune diseases.
• Imaging Tests: People with rheumatoid arthritis may need ultrasound or MRI scans to see if the joints are inflamed or damaged. Those with Sjögren’s syndrome may need an ultrasound of the salivary glands to determine if there are any abnormalities.
• Functional Tests: Sjögren’s syndrome patients may undergo a Schirmer’s test to measure tear production or a salivary flow rate test to evaluate the severity of dry mouth.

5. Treatment for These Diseases

Because RA and Sjögren’s syndrome share similar underlying mechanisms, some treatment methods are effective for both, while others are specific to each condition.

• Disease-Modifying Anti-Rheumatic Drugs (DMARDs): Medications like methotrexate can slow the progression of RA and can also be helpful in managing Sjögren’s syndrome.
• Biologics: Medications like rituximab help control the immune system response and reduce inflammation in both diseases.
• Local Treatments: Sjögren’s syndrome patients often use artificial tears to relieve dry eyes or saliva substitutes to reduce dry mouth. Rheumatoid arthritis patients may need localized steroid injections to reduce joint inflammation.
• Lifestyle Adjustments: Regular exercise, a balanced diet, and avoiding smoking can all help manage these conditions. Exercise can reduce joint stiffness and strengthen muscles, while staying hydrated and avoiding dry environments can help with symptoms of Sjögren’s syndrome.

6. Possible Complications

Having RA and Sjögren’s syndrome can increase the risk of certain complications, such as lymphoma, lung problems, and cardiovascular disease.

• Lymphoma: People with Sjögren’s syndrome have a higher risk of developing lymphoma, especially if they also have RA. This is due to chronic stimulation of the immune system, which can cause abnormal growth of lymphocytes.
• Lung Problems: Both RA and Sjögren’s syndrome can affect the lungs, leading to interstitial lung disease or pulmonary fibrosis, which can make breathing difficult.
• Cardiovascular Disease: Long-term inflammation increases the risk of heart disease. Patients need to be proactive in managing blood pressure, blood sugar, and cholesterol levels and maintaining a healthy lifestyle.

References

1. National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS). “Rheumatoid Arthritis.” Available at: https://www.niams.nih.gov/health-topics/rheumatoid-arthritis
2. American College of Rheumatology (ACR). “Sjögren’s Syndrome.” Available at: https://www.rheumatology.org/I-Am-A/Patient-Caregiver/Diseases-Conditions/Sjogrens-Syndrome
3. Ramos-Casals, M., Brito-Zeron, P., Sisó-Almirall, A., & Bootsma, H. (2012). “Primary Sjögren syndrome.” British Medical Journal. doi: 10.1136/bmj.e3821

Conclusion

Rheumatoid arthritis and Sjögren’s syndrome are two common autoimmune diseases that have many similar mechanisms and symptoms. While these diseases cannot currently be cured, patients can significantly reduce symptoms and improve their quality of life with a combination of medications, lifestyle adjustments, and other therapies. Hopefully, this article has helped patients and their families understand these conditions better and work with healthcare professionals to develop the best treatment plans.