Differential Diagnosis for Shoulder Pain
The patient's symptoms of shoulder pain with the arm in a dependent position, radiation to the clavicle, weakness with overhead lifts, crepitus felt with lateral raise, and occasional pain with deep breathing suggest several potential diagnoses. These can be categorized as follows:
Single Most Likely Diagnosis
- Subacromial Impingement Syndrome: This condition is characterized by inflammation of the tendons of the rotator cuff as they pass under the acromion, leading to pain, especially with overhead activities. The symptoms of pain with the arm in a dependent position, weakness with overhead lifts, and crepitus with lateral raise are classic for this diagnosis. Pain with deep breathing can occur if the inflammation irritates the adjacent structures.
Other Likely Diagnoses
- Rotator Cuff Tendinopathy: Similar to subacromial impingement, tendinopathy of the rotator cuff tendons can cause pain and weakness, especially with activities involving lifting or overhead movements. The presence of crepitus supports this diagnosis.
- Adhesive Capsulitis (Frozen Shoulder): Although typically characterized by a gradual loss of active and passive shoulder motion, early stages can present with pain and stiffness, potentially mimicking some of the symptoms described.
- Acromioclavicular Joint Arthritis: Pain localized to the acromioclavicular joint, which can radiate to the shoulder and clavicle, and worsen with activities such as lifting, could be a consideration.
Do Not Miss Diagnoses
- Pulmonary Embolism: Although less common, referred pain to the shoulder from a pulmonary embolism, especially if it worsens with deep breathing, is a critical diagnosis not to miss due to its high mortality rate if untreated.
- Myocardial Infarction: Referred shoulder pain, particularly if it radiates to the arm and is associated with exertion, could be a sign of a myocardial infarction, especially in patients with risk factors.
- Pancoast Tumor: A tumor located at the apex of the lung can cause shoulder pain due to invasion of the brachial plexus and adjacent structures, and it's crucial to consider this in patients with persistent, unexplained shoulder pain.
Rare Diagnoses
- Thoracic Outlet Syndrome: Compression of the nerves and/or blood vessels that pass into the thoracic outlet (the space between your collarbone and first rib) can cause shoulder and arm pain, among other symptoms.
- Scapulothoracic Bursitis: Inflammation of the bursae located between the scapula and the thoracic wall can cause pain, especially with movements that involve the scapula, such as lifting or deep breathing.