What is Subacromial Bursitis?
A bursa is a sac filled with fluid that can be found in various parts of the human body. Its main function is to lessen the wear and tear on joints and body parts that experience a lot of friction. One such place is the subacromial space in the shoulder.
The subacromial bursa is a specific fluid-filled sac located in the shoulder. It’s positioned under structures such as the acromion, coracoid, a ligament called the coracoacromial (CA), and the top part of the deltoid muscle. It’s also above the supraspinatus muscle fibers. The space it occupies in the shoulder is typically about 1.0 to 1.5 cm in height.
Whenever the bursa gets irritated or inflamed for various reasons, it results in a condition referred to as subacromial bursitis.
What Causes Subacromial Bursitis?
Any event that causes inflammation in the cushioning sac (bursa) beneath the acromion, a part of your shoulder blade, can result in bursitis, a painful condition. Here are some typical causes:
1. Subacromial impingement: This is when the tendons of the rotator cuff muscles get pinched in the shoulder space.
2. Regular overhead activities or overuse: Repetitive movements like those in sports or certain types of work can cause this issue.
3. Direct trauma: An injury to that area, such as a fall can cause bursitis.
4. Crystal deposition: Sometimes crystals, most often from uric acid, form in the bursa, causing inflammation.
5. Subacromial hemorrhage: This is internal bleeding in this part of your shoulder.
6. Infection: If germs enter your body — for example, through a cut — they can cause any area to become infected, including your bursa.
7. Autoimmune diseases: These are illnesses like rheumatoid arthritis that happen when the body’s immune system mistakenly attacks its own tissues, in this case causing inflammation in the bursa.
Risk Factors and Frequency for Subacromial Bursitis
Bursitis is a condition that causes about 0.4% of all primary care visits. This condition does not have a gender preference, meaning it can affect both men and women equally. It’s more common in people who are involved in repeat overhead activities, like athletes, factory workers, and manual laborers. Also, older people are more likely to experience a specific type of bursitis called subacromial bursitis. This is typically due to years of usage which results in more subacromial impingement, a condition where shoulder muscles rub against the top part of the shoulder blade.
Signs and Symptoms of Subacromial Bursitis
Subacromial bursitis is a medical condition that’s primarily identified through a clinical evaluation, which includes a comprehensive medical history and physical examination. People with this condition usually feel pain on the front-lateral part of their shoulder. Certain situations can hint towards a diagnosis, like injuries from a fall that impacted the shoulder directly, or a history of repetitive activities that require raising the arms, like playing overhead sports or lifting boxes.
One common cause of subacromial bursitis is impingement syndrome. This occurs when the gap under the shoulder bone, known as the subacromial space, shrinks, often due to activities that involve raising the arms. When we lift our arms, our upper arm bone comes closer to the shoulder bone, which shrinks this space where the protective fluid-filled sac called the subacromial bursa and a muscle called the supraspinatus are located. The subacromial bursa plays a crucial role in preventing wear and tear of the supraspinatus muscle from the constant rubbing between the upper arm and shoulder bones. However, repetitive movements can irritate and inflame the bursa. Therefore, when considering impingement syndrome as a potential cause, it’s vital to look for other problems like swelling or tearing of the supraspinatus tendon as they may coexist.
During a physical exam, patients typically feel pinpoint pain just below their shoulder bone when touched. This pain is usually localized and doesn’t spread to other parts of the shoulder or down the arm. However, if the pain does spread, a problem with the neck spine should be considered. The skin at this point might also feel warmer or spongier than usual, but redness is typically not observed. Moving their arm up beyond 75 to 80 degrees may also provoke pain, because this compresses the subacromial bursa beneath the shoulder bone.
Testing for Subacromial Bursitis
If you’re suffering from shoulder pain, your doctor wouldn’t normally run lab tests to diagnose the cause as routine results don’t usually provide the needed information. However, if the doctor is worried about a severe infection called septic arthritis, they might take a sample of the fluid in your shoulder joint for testing.
While imaging isn’t necessary to diagnose a common cause of shoulder pain called subacromial bursitis, your doctor might still opt to have X-rays done. This is to rule out other possible causes of your pain like fractures, dislocations, and osteoarthritis. Bear in mind that the bursa – a soft tissue found near your joints that helps to decrease rubbing – won’t be visible on an X-ray unless it’s become hardened with calcium. Your doctor can also look at the shape of your acromion, a part of your shoulder blade. Specific shapes can make you more likely to develop bursitis. For example, if your acromion is curved downwards or hooked, there may be less room for your tendons to move, increasing the likelihood of irritation and bursitis.
Other imaging methods like MRI and ultrasound can also be helpful in some cases. MRI can show fluid buildup in the bursa and also provide a detailed view of the muscles and tendons in the rotator cuff of your shoulder. An ultrasound could be helpful in measuring the thickness of your bursa. Although not frequently used for diagnosis, in expert hands, an ultrasound can provide valuable information.
Treatment Options for Subacromial Bursitis
Subacromial bursitis, an inflammation of the bursa located between the shoulder joint and the top of the shoulder blade, is typically treated without surgery. Usually, doctors recommend rest, over-the-counter anti-inflammatory medicines (known as Non-Steroidal Anti-Inflammatory Drugs or NSAIDs), physical therapy, and corticosteroid injections (a type of medicine to reduce inflammation). In some instances, ultrasound therapy may be used; however, research does not clearly support its effectiveness.
Surgery is generally reserved for severe cases where these non-surgical treatments do not provide relief from symptoms. A bursectomy, which is the removal of the inflamed bursa, can be performed. This procedure can take place either arthroscopically (a minimally invasive surgical procedure) or using an open approach which involves a larger incision.
If surgery is necessary, additional procedures can be carried out at the same if required, such as subacromial decompression (creating more space for the rotator cuff to avoid irritation), or rotator cuff repair (mending a torn or damaged rotator cuff, which is a group of muscles and tendons that surround the shoulder joint).
What else can Subacromial Bursitis be?
The following are some medical conditions that can cause shoulder pain:
- Impingement syndrome, where the shoulder muscles rub against the part of the shoulder blade.
- Rotator cuff tendinitis or tear, an irritation or damage to the group of muscles and tendons that stabilize the shoulder joint.
- Biceps tendinitis, which is inflammation or damage to the upper biceps tendon.
- Adhesive capsulitis, also known as frozen shoulder, where the shoulder capsule becomes inflamed and stiff, restricting its movement.
- Acromioclavicular joint osteoarthritis, a form of arthritis affecting the joint at the top of the shoulder.
What to expect with Subacromial Bursitis
The outlook for a condition called subacromial bursitis is generally positive. Most patients find their condition improves with basic treatments. However, for those who don’t see improvement, surgery can be an option. It’s worth noting that age can have an influence, with older patients often experiencing less successful results.
In most cases, subacromial bursitis doesn’t last forever and doesn’t have a lasting impact on day-to-day activities.
Possible Complications When Diagnosed with Subacromial Bursitis
Subacromial bursitis is a condition affecting the shoulder and it generally doesn’t lead to many complications. However, repeatedly injecting steroids into the affected region can potentially cause infection in the skin or shoulder. There’s also a risk of damaging the group of muscles in the shoulder called the rotator cuff. Despite these concerns, a study by Bhatia and colleagues found no substantial difference in the incidence of rotator cuff tears between patients who received less than or more than three steroid injections in the subacromial region.
- Risk of skin or shoulder joint infection
- Possible damage to rotator cuff muscles
- No significant difference in rotator cuff tears with less or more steroid injections.
Preventing Subacromial Bursitis
Subacromial bursitis is a condition that often causes shoulder pain. This happens when the bursa, a small cushion-like sac located under a part of the shoulder called the acromion, becomes inflamed. This usually occurs as a result of repetitive activities that require using the shoulder to lift or move items overhead, or after experiencing a trauma or injury.
To ease the symptoms and help the shoulder heal, it’s effective to stop or limit these overhead activities, and to rest the shoulder. Over-the-counter anti-inflammatory drugs, known as NSAIDs, can also help. For long-lasting or severe cases, your doctor may use treatments like steroid injections or, in rare cases, surgery.
