Differential Diagnosis for Pain on External Rotation of Left Shoulder in a 45-year-old Male with No Injury
- Single most likely diagnosis
- Subacromial Impingement Syndrome: This condition is a common cause of shoulder pain, especially in individuals who frequently use their shoulders for lifting or overhead activities. The pain on external rotation can be due to the mechanical pinching of the rotator cuff tendons under the acromion.
- Other Likely diagnoses
- Rotator Cuff Tendinopathy: Wear and tear on the rotator cuff tendons can cause pain, especially with movements like external rotation. This condition is common in middle-aged individuals and can be related to repetitive strain or age-related degeneration.
- Adhesive Capsulitis (Frozen Shoulder): Although typically associated with limited range of motion and pain at the end ranges, early stages of frozen shoulder can present with pain on specific movements like external rotation without significant restriction.
- Bicipital Tendinopathy: Inflammation of the long head of the biceps tendon can cause anterior shoulder pain that may radiate and could be exacerbated by external rotation, depending on the specific activities and positions that irritate the tendon.
- Do Not Miss diagnoses
- Axillary Nerve Compression or Injury: While less common, compression or injury to the axillary nerve can cause pain and weakness, particularly with external rotation. Missing this diagnosis could lead to prolonged disability.
- Thoracic Outlet Syndrome: This condition involves compression of the nerves and/or blood vessels that pass into the thoracic outlet (the space between your collarbone and first rib). It can cause shoulder pain and might be exacerbated by certain movements, including external rotation.
- Referred Pain from Cervical Spine: Cervical spine disorders, such as a herniated disc or cervical spondylosis, can refer pain to the shoulder region. Although the primary complaint is shoulder pain, the underlying cause could be cervical in origin, making it crucial not to miss.
- Rare diagnoses
- Infectious or Inflammatory Arthritis: Conditions like septic arthritis or rheumatoid arthritis can cause shoulder pain but are less common and usually present with additional systemic symptoms or signs of inflammation.
- Tumors: Both benign and malignant tumors can occur in the shoulder region and cause pain. These are rare but important to consider in the differential diagnosis to ensure timely and appropriate treatment.