When most people think of arthritis, they picture stiff, aching joints and chronic pain. While defined by joint inflammation and damage, its effects can extend beyond the joint capsule. A less common but concerning symptom is paresthesia, which describes the feeling of numbness, tingling, or “pins and needles” in the limbs. This sensation indicates that the joint disease is interfering with the nervous system.
How Arthritis Causes Nerve Interference
The progression of arthritis disrupts the peripheral nervous system through both mechanical and biochemical means. Damaged or inflamed joints mechanically compress nearby nerves, which drives the numbness and tingling experienced by some individuals.
Mechanical Compression
A key mechanical factor is the formation of bony growths called osteophytes, or bone spurs, which develop in response to cartilage breakdown in osteoarthritis. If these spurs form in the spine, they can narrow the openings where nerve roots exit. This direct pressure causes symptoms like numbness or weakness to radiate into the arms or legs.
Inflammatory Compression
In inflammatory arthritis, swelling of the soft tissues is a significant cause of nerve interference. Chronic inflammation causes the synovium (joint lining) and surrounding tendons to thicken and swell. This enlarged tissue mass presses on an adjacent nerve, impairing its ability to transmit signals properly. This results in the characteristic tingling or loss of sensation.
Structural changes also contribute to nerve irritation. Cartilage damage can destabilize the joint, causing it to shift slightly out of alignment and pinch a nerve. Inflammatory mediators released during a flare-up can also chemically sensitize the nerves, making them more reactive to pressure.
Specific Forms of Arthritis Linked to Numbness
Different types of arthritis affect the nervous system distinctly, often depending on which joints are primarily involved.
Osteoarthritis (OA)
OA frequently causes nerve symptoms when it affects the spine. Degeneration of spinal joints can lead to spinal stenosis, a narrowing of the spinal canal or the neural foramina. This narrowing causes radiculopathy, where the compressed nerve root radiates pain, tingling, and numbness down the limb. OA can also cause localized nerve entrapment in the hands and wrists. Damage to wrist joints can alter the structure of the carpal tunnel, leading to Carpal Tunnel Syndrome. This results in numbness and tingling in the thumb, index, middle, and half of the ring finger.
Rheumatoid Arthritis (RA)
RA is an autoimmune disorder that involves the nervous system through systemic inflammation and joint instability. Inflammation can spread beyond the joint capsule, sometimes causing vasculitis (inflammation of the blood vessels). This restricts blood flow to the nerves, resulting in peripheral neuropathy. A serious complication of RA involves the cervical spine (neck), where joint instability can lead to atlantoaxial subluxation. This partial dislocation of the first two vertebrae puts direct pressure on the spinal cord, causing extensive numbness, weakness, and altered reflexes.
Other Forms of Arthritis
Less common forms of arthritis also cause nerve symptoms through localized pressure. Gout involves the formation of sharp, crystal deposits called tophi near joints. If a tophus forms near a peripheral nerve, the localized mass can physically impinge on it. Psoriatic Arthritis can similarly cause severe localized swelling that compresses nerves, typically due to acute inflammation.
When Numbness and Tingling Require Medical Attention
While mild, intermittent tingling can be a consequence of chronic arthritis, certain symptoms indicate a more serious problem requiring prompt medical evaluation. Any numbness or tingling that begins suddenly, progresses rapidly, or affects both sides of the body simultaneously should be investigated immediately. These changes suggest acute nerve compression or a widespread neurological event.
A particularly concerning sign is the loss of motor function, such as sudden muscle weakness, foot drop, or difficulty gripping objects. These motor deficits indicate that the pressure is severe enough to affect the nerves responsible for muscle control. Doctors use diagnostic tools like Magnetic Resonance Imaging (MRI) or Nerve Conduction Studies (NCS) to identify the precise location and extent of the nerve damage.
The most urgent symptoms involve the central nervous system, specifically the spinal cord. The sudden onset of numbness in the saddle area (groin and buttocks), accompanied by new difficulty controlling the bladder or bowels, signals a medical emergency called Cauda Equina Syndrome. This severe compression of the nerve roots requires immediate surgical decompression to prevent permanent paralysis.
Treatment for nerve symptoms related to arthritis focuses on managing the underlying joint disease and relieving pressure on the affected nerve. This may involve:
- Adjusting medication to reduce inflammation.
- Physical therapy to improve joint stability.
- Corticosteroid injections to decrease local swelling.
In cases where bone spurs or severe joint instability cause persistent, debilitating compression, surgery may be necessary to decompress the nerve and restore its function.