Shoulder bursitis is a very common condition in which the area surrounding the shoulder tendons becomes irritated. Many cases develop after increasing activity while others develop slowly over time as a result of degenerative changes around the shoulder. This condition is very common in patients between the ages of 40 and 55. Most patients do not remember an injury prior to their symptoms. Overhead activities tend to aggravate the inflammation. Many patients have a difficult time sleeping because their shoulder seems to hurt worse after laying down. The pain from bursitis is usually not felt in the shoulder but along the upper, outer arm in the area of the deltoid muscle.
The cause of sub-acromial bursitis is not well understood but there appear to be two mechanisms for developing symptoms. The first type is mechanical pinching of the bursa or rotator cuff tendon leading to inflammation. Most patients with bursitis have extra calcium deposits on the anterior lip of the acromion, a plate like bone on the top of the shoulder. With activity, this extra calcium can cause mechanical pinching of the rotator cuff tendons especially with repetitive overhead activity. Once the tendon and bursa are inflamed, they tend to swell and this leads to even less clearance under the acromion. This sets up a vicious cycle of inflammation and swelling that persists until the calcium deposits are removed.
The second type of bursitis is the result of an overuse injury which causes inflammation of the bursa and tendon. This type tends to be more sudden in onset with very sharp pain in the shoulder and arm. Unlike impingement, this type of bursitis is often cured with one or two corticosteroid injections.
Initial treatment includes activity modification, anti-inflammatory medication and corticosteroid injection. If the condition persists, physical therapy is often helpful. In refractory cases, an MRI and occasionally surgery is required to remove the inflamed bursa. This is done as an outpatient procedure with minimally invasive arthroscopic techniques.