THE CLINICAL SYNDROME

• The primary location of the subdeltoid bursa is under the acromion, and it extends laterally between the deltoid muscle and the joint capsule that is located under the deltoid muscle.

• It is possible for it to take the form of a single bursal sac, but in some patients it can also take the form of a multisegmented series of loculated sacs.

• Injury to the subdeltoid bursa can occur as a result of either a single severe blow or a series of smaller, more frequent blows.

• When participating in sports or falling off a bicycle, acute injuries frequently take the form of direct trauma to the shoulder.

• These injuries can be very painful.

• Inflammation of the subdeltoid bursa can be caused by activities such as throwing, bowling, carrying a heavy briefcase, working with the arm raised across the body, rotator cuff injuries, or repetitive motion associated with assembly line work.

• Other causes include working with the arm raised across the body and working with the arm lowered across the body.

• Calcification of the bursa can occur if the inflammation persists for an extended period of time.

SIGNS AND SYMPTOMS

• During a physical examination, point tenderness may be found over the acromion.

• In some cases, swelling of the bursa causes the affected deltoid muscle to have an edematous feel.

• The pain is brought on by resisted abduction and lateral rotation of the affected shoulder, as well as by passive elevation and medial rotation of the affected shoulder.

• During this maneuver, a sudden release of resistance causes a significant increase in the amount of pain experienced.

• A tear in the rotator cuff may mimic or coexist with subdeltoid bursitis, which can make the diagnosis more difficult.

TESTING

• The presence of calcification of the bursa and associated structures on plain radiographs of the shoulder is consistent with the presence of chronic inflammation.

• If there is any suspicion of tendinitis, a partial disruption of the ligaments, or a tear in the rotator cuff, magnetic resonance imaging is the test that should be performed.

• Imaging with ultrasound may provide additional insight into the reason why the patient is in so much discomfort.

• The clinical presentation of the patient may suggest the need for additional testing, which may include an evaluation of the patient's complete blood count, erythrocyte sedimentation rate, and antinuclear antibody levels.

• If there is a possibility of metastatic disease or a primary tumor involving the shoulder, then radionuclide bone scanning is something that should be done.

• The injection technique that will be described later can be utilized both as a diagnostic tool and a treatment strategy.

DIFFERENTIAL DIAGNOSIS

• One of the most common reasons for pain in the shoulder joint is a condition called subdeltoid bursitis.

• In addition to subdeltoid bursitis, other common causes of shoulder pain such as osteoarthritis, rheumatoid arthritis, posttraumatic arthritis, and rotator cuff arthropathy may all be present at the same time.

• Shoulder pain that is caused by arthritis can also be caused by collagen vascular diseases, infections, villonodular synovitis, and Lyme disease, although these are less common causes.

• In most cases, acute infectious arthritis is accompanied by significant systemic symptoms, such as fever and malaise, and it should be easy to recognize; the condition is treated with culture and antibiotics rather than injection therapy.

• Shoulder pain that is caused by collagen vascular disease responds exceptionally well to the injection technique that is described in this article. In general, collagen vascular diseases manifest as polyarthropathy rather than monarthropathy that is limited to the shoulder joint.

TREATMENT

• The initial treatment for the pain and functional disability associated with subdeltoid bursitis consists of a combination of physical therapy and nonsteroidal anti-inflammatory drugs (NSAIDs) or cyclooxygenase-2 inhibitors.

• Both of these classes of medications are anti-inflammatory.

• The application of heat and cold to specific areas of the body may also be beneficial.

• Patients who do not respond to these treatment modalities may benefit from receiving an injection of a local anesthetic and steroid into the subdeltoid bursa as the next step in the treatment process.

COMPLICATIONS AND PITFALLS

• If the clinically relevant anatomy is carefully considered before administering the injection, this method does not pose a safety risk. In order to prevent infection, sterile technique must be utilized, and universal precautions must be taken in order to lessen the likelihood that the operator will be put in harm's way.

• If pressure is applied to the injection site immediately after the injection, this can help reduce the risk of complications such as ecchymosis and hematoma formation.

• Infection is the most significant risk associated with injection into the subdeltoid bursa; however, this risk should be extremely low if proper aseptic technique is adhered to throughout the procedure.

• After receiving an injection into the subdeltoid bursa, approximately one quarter of patients experience a temporary increase in the level of pain they are experiencing.

• Patients should be made aware of the possibility that this will occur.