ArthritiChrissy

The Hidden Nervous System Connection

When I was diagnosed with rheumatoid arthritis (RA) in 2021, I initially thought “ok, so my immune system is attacking my joints. I’ll take these meds and hopefully my joints will feel better”. Notice how 100% of the focus is on JOINTS. However, I quickly learned that joint pain is just the tip of the arthritis iceberg.

It turns out RA doesn’t just mess with your joints. Inflammation goes after all kinds of other systems in your body. These can include your heart, lungs, eyes, skin, and even nervous system!

Your Nerves Are Part of the Story, Too

I was surprised to learn that, in uncommon cases, RA’s inflammation can reach the central nervous system. This could mean inflammation in the brain itself, in the spinal cord, or even the formation of nodules in the brain.⁽¹⁾

Let’s discuss a few ways chronic inflammation can show up as nervous system symptoms.

Pins and Needles: Peripheral Neuropathy

40%-45% of RA patients will experience some type of peripheral neuropathy (like me!).^{(2, 3)} The most common cause is compression neuropathy, where inflammation and swelling puts pressure on nerves. Carpel tunnel can be a form of compression neuropathy (and affects about 10% of people who have RA).⁽⁴⁾ Other forms of compression neuropathy include tarsal tunnel syndrome (in feet and ankles), ulnar nerve compression at the elbow, peroneal nerve compression near the knee, and interdigital nerve compression in the toes. Ouch!

You can even experience compression neuropathy but not feel pain! In a small study using electrophysiology testing, about two-thirds of RA patients who had nerve compression felt no pain or other symptoms.⁽⁵⁾ Our nerves are being affected even when we don’t feel it!

What Can You Do?

Know the signs of neuropathy: tingling, numbness, burning, or weakness. These are especially felt in hands, wrists, and feet. Talk to your doctor if you have these symptoms – early detection can prevent permanent nerve damage and increase the number of treatment options available to you.

Brain Fog is Real!

Where did I put my keys? What’s her name again? Why did I walk into the kitchen?

I’ve tried to blame the forgetful moments of brain fog on being tired, stressed, or just getting older. But cognitive dysfunction shows up in ~30% of RA patients.⁽⁷⁾ When researchers test RA patients on memory, verbal communication, attention & concentration, and problem-solving, we consistently score lower than healthy people.⁽⁸⁾

*Have you ever tried writing a blog post with a section about brain fog, but your brain fog is preventing you from remembering any of the numerous stories you have about brain fog, and then you realize you’re IN a brain fog story? BRAINFOGCEPTION.

What’s Causing Brain Fog?

The relationship between RA and cognitive impairment is complicated, but here are a few connections that researchers have identified:

Chronic Inflammation

Inflammatory chemicals like tumor necrosis factor (the same TNF we block with biologics like Humira and Enbrel) can rewire how our brains work.⁽⁸⁾ Brain cells start talking to each other differently and their communication patterns shift.⁽⁹⁾

Neuroinflammation

It turns out your brain has its own immune response! When you have systemic inflammation from RA, that can trigger neuroinflammation. Studies using functional MRI have shown that RA patients who respond to TNF inhibitors have increased activity in certain areas of the brain compared to people who do not respond to TNF inhibitors.⁽¹⁰⁾ In other words, neuroinflammation is changing how our brains process information.

Cardiovascular Factors

Systemic inflammation caused by RA increases the chance of narrowed or blocked arteries in the brain. These blockages can cause problems with memory, reasoning, and thinking. This cognitive impairment has also been linked to cardiovascular risk factors like high cholesterol and high blood pressure.⁽⁷⁾

The Medication Factor

Turns out the meds we take to fight RA can cause cognitive problems of their own. Research has found a higher risk of developing dementia in people who are taking methotrexate and other DMARDs. This is compared to people taking other medications. Corticosteroids like prednisone, especially at higher doses, can cause mood changes, confusion, and cognitive issues, especially in women.⁽¹¹⁾ Make sure to discuss any medication side effects or changes with your doctor before changing your treatment plan!!

Depression, Pain, and Fatigue

When your brain is constantly dealing with pain signals, it may have fewer resources for memory or attention tasks. Scientists have discovered that the brain circuits that handle thinking and the ones that process pain are deeply intertwined. They actually influence each other. When one is overwhelmed it affects the other.⁽¹²⁾

A large CDC study, however, showed that cognition was no different in RA patients than in older adults. What this study DID show, was that other possible symptoms of RA such as a sedentary lifestyle and depression affected cognition. Depression is also common in rheumatoid arthritis patients, but it can be hard to figure out if cognitive issues are being caused by the depression or the RA. A real chicken or egg situation.⁽⁸⁾

Pain can also interfere with sleep, leading to reduced cognitive function.

What Can You Do?

Don’t accept defeat to RA brain fog! Track when it’s worse to see if it aligns with flares, medication changes, or poor sleep. Talk to your doctor, and focus on things you can change such as staying active, getting good sleep, managing depression, and keeping your cardiovascular system healthy. Motion is lotion for your joints AND your brain.

Central Sensitization

You’ve probably heard stories or even experienced this yourself: your bloodwork looks great, but you’re still in pain. Central sensitization is when pain signals get “boosted” by the nervous system.^{(13, 14)} This can cause more sensitivity to pain, or cause you to feel pain from things that are usually not painful.⁽¹⁵⁾

Almost half of all RA patients may not show signs of inflammation, while still reporting pain and sleep disturbance. This indicates they may be experiencing sensitization.⁽¹⁴⁾ The quintessential central sensitization syndrome is fibromyalgia, which about one third of RA patients may have.⁽¹³⁾

What Can You Do?

Talk to your doctor if your pain seems disproportionate to your disease activity. There may be pharmaceutical and non-pharmaceutical interventions that can help.

The Autonomic Connection: Your Body’s Autopilot System

This was the topic I found most interesting when researching the connection between RA and the nervous system. Your autonomic nervous system controls things like blood pressure, heart rate, digestion…things your body does automatically without you thinking about them. These functions can be disrupted by RA.

Researchers have given this connection its own name: “immune-autonomics.” It’s a whole field of study looking at how these two systems interact.

Studies show that people who have RA have reduced heart rate variability (HRV), decreased ability to regulate blood pressure, and autonomic dysfunction from increased levels of inflammation.

Perhaps you’ve heard about developments in vagus nerve stimulation as a potential treatment for RA.⁽¹⁶⁾ This treatment may work by stabilizing the immune-autonomic balance.

What Does This All Mean?

Understanding the connection between your RA and nervous system can help you better manage your rheumatoid arthritis.

Advocate for Comprehensive Care

Many rheumatologists are focused on caring for your joints. But if you are experiencing neurological symptoms, bring those up with your doctor, too. Those symptoms could be:

• Tingling, numbness, burning
• Brain fog
• Pain that seems more intense than disease activity
• Changes in mood or cognition

Get Tested If Needed

If you think you are experiencing nerve compression, you can ask your doctor about nerve conduction tests. If you feel like you are experiencing significant cognitive issues your doctor may have tests for this as well. Testing is the first step to treating potential issues.

Focus on Lifestyle Factors

• Exercising regularly (motion is lotion!)⁽⁸⁾
• Prioritizing sleep
• Managing stress
• Eating an anti-inflammatory diet
• Addressing depression and anxiety⁽¹⁷⁾

Be Prepared for Appointments

Time with your rheumatologist is limited. It can be helpful to prepare notes with prioritized issues, in order to quickly and effectively communicate with your doctor.⁽¹⁸⁾ Specific examples and how they are affecting your daily activities can be helpful. You may need to be persistent in communicating symptoms to your doctor!

Stay Informed

Science around autoimmune disease and the nervous system is always evolving. Understanding your symptoms and being aware of emerging treatment options can help you make better-informed decisions about your personal treatment plan.

The Bottom Line

Rheumatoid arthritis isn’t just joint pain! Many parts of your body are subject to chronic inflammation, and your nervous system is no exception. From peripheral neuropathy to brain fog, neurological symptoms are real and deserve attention.

Understanding these symptoms and connection to RA enables us to advocate more effectively for testing and treatment. This advocacy can hopefully lead to an improved quality of life.

You’re not imaging your symptoms, and don’t have to accept them as inevitable or untreatable.

I Want to Know…

Have you experienced any of these symptoms or conditions? What has helped you manage them? Please share your experiences in the comments – learning from our community is invaluable!

This blog post is for educational purposes and reflects my personal experience and research. Always consult with your healthcare providers about your specific situation and any changes to your treatment plan.

References

[1] Atzeni, Fabiola, et al. “Central Nervous System Involvement in Rheumatoid Arthritis Patients and the Potential Implications of Using Biological Agents.” Best Practice & Research Clinical Rheumatology, vol. 32, no. 4, Aug. 2018, pp. 500–510, https://doi.org/10.1016/j.berh.2019.02.003. Accessed 1 Nov. 2020.

[2] Chapman, Joab. “Rheumatoid Arthritis: Peripheral and Central Nervous System Involvement.” Handbook of Systemic Autoimmune Diseases, vol. 3, Elsevier, 28 Sept. 2007, pp. 97–105, www.sciencedirect.com/science/article/abs/pii/S1571507804030065.

[3] Cox, Caitlin. “Rheumatoid Arthritis and Neuropathy.” WebMD, 29 Mar. 2022, www.webmd.com/rheumatoid-arthritis/ra-neuropathy.

[4] Rajeshwari, Bhavya, and Sunil Kumar. “Rheumatoid Neuropathy: A Brief Overview.” Cureus, vol. 15, no. 1, 24 Jan. 2023, https://doi.org/10.7759/cureus.34127.

[5] Lanzillo, B, et al. “Subclinical Peripheral Nerve Involvement in Patients with Rheumatoid Arthritis.” Arthritis and Rheumatism, vol. 41, no. 7, July 1998, pp. 1196–202, https://doi.org/10.1002/1529-0131(199807)41:7%3C1196::AID-ART8%3E3.0.CO;2-R.

[6] Seed, Shawna. “What Is de Quervain’s Disease?” WebMD, www.webmd.com/rheumatoid-arthritis/de-quervains-disease.

[7] Shin, So Young, et al. “Cognitive Impairment in Persons with Rheumatoid Arthritis.” Arthritis Care & Research, vol. 64, no. 8, 2012, p. n/a-n/a, https://doi.org/10.1002/acr.21683.

[8] Rath, Linda. “RA’s Effect on Your Brain.” Www.arthritis.org, 2023, www.arthritis.org/diseases/more-about/ra-effect-on-the-brain.

[9] Fletcher, Jenna. “Brain Fog and Rheumatoid Arthritis: What Is the Link?” Www.medicalnewstoday.com, 1 Mar. 2022, www.medicalnewstoday.com/articles/323212#whats-the-link.

[10] Fuggle, Nicholas R., et al. “New Insights into the Impact of Neuro-Inflammation in Rheumatoid Arthritis.” Frontiers in Neuroscience, vol. 8, 6 Nov. 2014, https://doi.org/10.3389/fnins.2014.00357.

[11] Alexandra Benisek. “Can Rheumatoid Arthritis Cause Brain Fog?” WebMD, www.webmd.com/rheumatoid-arthritis/ra-brain-fog.

[12] Chaurasia, Neha, et al. “Cognitive Dysfunction in Patients of Rheumatoid Arthritis.” Journal of Family Medicine and Primary Care, vol. 9, no. 5, 2020, p. 2219, https://doi.org/10.4103/jfmpc.jfmpc_307_20.

[13] Harte, Steven E., et al. “The Neurobiology of Central Sensitization.” Journal of Applied Biobehavioral Research, vol. 23, no. 2, June 2018, p. e12137, https://doi.org/10.1111/jabr.12137.

[14] Nijs, Jo, et al. “Central Sensitisation in Chronic Pain Conditions: Latest Discoveries and Their Potential for Precision Medicine.” The Lancet Rheumatology, vol. 3, no. 5, May 2021, https://doi.org/10.1016/s2665-9913(21)00032-1.

[15] “Understanding Centralized Pain.” Www.arthritis.org, www.arthritis.org/health-wellness/healthy-living/managing-pain/understanding-pain/understanding-centralized-pain.

[16] Ingegnoli, Francesca, et al. “The Link between Autonomic Nervous System and Rheumatoid Arthritis: From Bench to Bedside.” Frontiers in Medicine, vol. 7, 7 Dec. 2020, p. 589079, https://doi.org/10.3389/fmed.2020.589079.

[17] “Navigating Brain Fog with Arthritis.” Arthritisresearch.ca, 2025, www.arthritisresearch.ca/arthritis-and-brain-fog/.

[18] “Crushing Fatigue & Brain Fog: Must-Know Insights from Rheumatic Disease Experts | ACR 2024 with Deb.” Aiarthritis.org, 8 Apr. 2025, www.aiarthritis.org/acr24-fatigue. Accessed 8 Nov. 2025.