Bursitis is a common condition resulting from the inflammation of the bursa, a small, fluid-filled sac found near joints throughout the body. Bursae function as cushions, reducing friction between bones, tendons, and muscles to ensure smooth movement. When irritated, typically due to repetitive motions or injury, the bursa swells with fluid, causing localized pain. This resulting swelling can sometimes lead to a secondary symptom: numbness. This article explores the physiological connection between an inflamed bursa and the development of sensory changes like numbness and tingling.
Understanding Bursitis and Primary Symptoms
Bursae are located in areas of the body where soft tissues slide over bony prominences, such as the shoulders, elbows, hips, and knees. Their primary function is to facilitate movement in the musculoskeletal system by acting as a shock absorber. When this sac is subjected to excessive pressure or overuse, it becomes irritated, leading to the condition known as bursitis.
The most typical and direct symptoms stem from the inflammation itself, manifesting as localized physical discomfort. These primary signs include pain, often described as a dull ache, particularly when moving the affected joint or applying pressure to the area. Swelling, tenderness, and a noticeable restriction in the joint’s range of motion are hallmarks of the condition. Numbness or tingling is not a direct result of the bursa’s inflammation but a potential consequence of its physical enlargement.
The Mechanism: When Enlarged Bursae Impinge Nerves
The development of numbness, tingling, or a “pins and needles” sensation is often a secondary symptom, arising when the inflamed bursa expands and physically presses against an adjacent peripheral nerve. This mechanical pressure is a form of entrapment neuropathy, where the nerve’s ability to transmit sensory signals is compromised. The swollen bursa, confined within the joint structure, can narrow the space available for surrounding structures, directly irritating a nearby nerve.
In the shoulder, for instance, an inflamed subacromial bursa can swell and impinge upon nerves that pass beneath the acromion bone, potentially causing numbness or tingling sensations that travel down the arm. A common example occurs at the elbow, where olecranon bursitis—the inflammation of the sac at the point of the elbow—can swell significantly. Because a major nerve runs very close to the olecranon bursa, the enlarged sac can compress this nerve, leading to sensory changes in the forearm and hand.
This mechanism of nerve compression can also be seen in the hip, where trochanteric bursitis can cause swelling sufficient to lead to tingling in the upper thigh. The sensation of numbness or paresthesia is a direct result of the nerve being mechanically irritated or compressed by the increased fluid and size of the inflamed sac. Therefore, while the bursa itself causes pain, the physical mass of the enlarged bursa is what causes the sensory disturbance.
Identifying Urgent Signs and Associated Conditions
While mild tingling can be related to bursitis, certain signs indicate a need for immediate medical evaluation, as they may suggest severe nerve involvement or a different underlying issue. Sudden or complete inability to move the affected limb, significant muscle weakness, or sharp, shooting pains that travel far from the joint require prompt attention. These symptoms can signal a more severe degree of nerve damage beyond simple pressure.
Localized numbness can also be caused by conditions other than bursitis, necessitating a differential diagnosis. Issues like carpal tunnel syndrome, which involves nerve compression at the wrist, or a herniated spinal disc can produce similar sensory symptoms in the extremities. Additionally, if the bursitis is accompanied by signs of infection, such as fever, excessive redness, or warmth that spreads, urgent care is required to prevent the infection from spreading to the joint or bloodstream.
Treatment Strategies for Relieving Compression
The primary goal of treating bursitis-related numbness is to reduce the volume of the inflamed bursa, thereby removing the pressure on the adjacent nerve. Conservative treatments often begin with the RICE method: resting the joint and applying ice to reduce inflammation and swelling. Non-steroidal anti-inflammatory drugs (NSAIDs) like ibuprofen are frequently used to decrease the inflammatory response within the bursa sac.
Physical therapy can be instrumental by improving joint mechanics and strengthening the surrounding muscles, which helps reduce friction and strain on the bursa. If conservative measures fail to alleviate nerve compression, a medical professional may recommend a corticosteroid injection directly into the bursa. The steroid is a powerful anti-inflammatory agent that rapidly shrinks the bursa, offering quick relief from nerve pressure. In severe cases where compression persists and causes progressive nerve damage, a surgical procedure called a bursectomy, which removes the inflamed sac, may be required to permanently decompress the nerve.