Rheumatoid arthritis (RA) is a chronic inflammatory autoimmune disease primarily recognized for causing pain and swelling in the joints. The systemic nature of RA means the disease can affect tissues and organs beyond the joints, including the nervous system. Damage to the peripheral nerves, known as peripheral neuropathy, is a recognized complication of rheumatoid arthritis. This nerve damage occurs because the underlying disease process creates an environment hostile to healthy nerve function. Up to 50% of individuals with RA may develop some form of peripheral neuropathy during the course of their disease.
How Rheumatoid Arthritis Affects the Nerves
The active disease process in rheumatoid arthritis leads to nerve damage through two distinct biological pathways: systemic inflammation and mechanical compression. The systemic inflammation associated with RA can target the small blood vessels that supply oxygen and nutrients to the nerves themselves, a condition known as vasculitis. When these blood vessels become inflamed, the blood flow to the nerve fibers is restricted, leading to nerve ischemia. This lack of adequate blood supply starves the nerve of what it needs to function and survive, causing damage and dysfunction.
This systemic damage often results in a widespread pattern of neuropathy affecting multiple nerves simultaneously. The characteristic joint inflammation and swelling within RA can also directly injure nearby nerves through physical entrapment. Proliferative synovitis, or inflammation of the synovial membrane lining the joints, causes tissues to swell and thicken. This swelling creates pressure on adjacent nerves passing through confined spaces, such as the wrist or ankle. Joint deformities or partial dislocations that occur as the disease progresses can also contribute to this mechanical compression.
Specific Forms of Nerve Damage Linked to RA
Neuropathy in RA is categorized based on whether the damage is localized due to compression or widespread due to systemic inflammation. The most common presentation is entrapment neuropathy, resulting from the mechanical compression of a single nerve by inflamed tissue. Carpal Tunnel Syndrome (CTS) is the most frequent type, where inflammation in the wrist compresses the median nerve, causing numbness and tingling in the hand and fingers. Tarsal Tunnel Syndrome similarly results from the compression of the tibial nerve near the ankle, leading to symptoms in the toes and feet.
Less common, but often more severe, are forms of neuropathy linked to active systemic inflammation and vasculitis. Symmetrical polyneuropathy involves damage to many nerves on both sides of the body, often presenting as a “glove and stocking” pattern of sensory loss in the hands and feet. Mononeuritis multiplex is an inflammatory neuropathy characterized by damage to two or more separate nerve areas, causing motor weakness and significant pain. This form is strongly associated with active rheumatoid vasculitis.
Identifying Nerve Symptoms and Confirming the Diagnosis
Recognizing the symptoms of RA-induced neuropathy can be challenging because they may overlap with general arthritis pain and stiffness. Sensory symptoms include burning, stabbing, or shooting pain, along with tingling or a “pins-and-needles” sensation, particularly in the extremities. Motor nerve involvement can cause muscle weakness, loss of coordination, difficulty walking, or reduced reflexes. Patients may also describe a feeling of wearing invisible gloves or socks.
To confirm a diagnosis and distinguish neuropathy from other causes, a physician performs a thorough clinical examination, assessing reflexes, strength, and sensation. Diagnostic tests are often necessary to pinpoint the exact site and severity of the damage. Nerve conduction studies (NCS) measure how quickly electrical signals move through the nerves, while electromyography (EMG) assesses the electrical activity of muscles. These tests help determine if the problem is due to nerve compression or a more generalized inflammatory process. Blood tests are also usually performed to rule out other common causes of neuropathy, such as diabetes or vitamin deficiencies.
Treatment Approaches for RA-Induced Neuropathy
The most effective treatment strategy for neuropathy caused by rheumatoid arthritis involves managing the underlying autoimmune disease. Reducing systemic inflammation with disease-modifying antirheumatic drugs (DMARDs) and biologics is essential. Controlling RA disease activity helps reduce vasculitis and joint swelling, addressing the root causes of both inflammatory and compressive nerve damage. Successfully treating the RA can prevent further nerve damage and allow damaged nerves time to heal.
In addition to controlling the underlying disease, symptomatic management is employed to relieve discomfort. Medications that alter how nerves send pain signals, such as certain anti-seizure drugs (e.g., gabapentin) or specific antidepressants, are commonly prescribed for neuropathic pain. For localized entrapment neuropathies like Carpal Tunnel Syndrome, non-surgical approaches include splinting, physical therapy, or corticosteroid injections. If conservative measures fail and compression is severe, surgical decompression may be necessary to relieve the pressure on the nerve.