Differential Diagnosis of Non-Traumatic Right Shoulder Pain
The differential diagnosis of non-traumatic shoulder pain in adults is primarily age-dependent: in patients over 35-40 years, rotator cuff disease and degenerative changes predominate, while in younger patients under 35 years, instability and labral pathology are more common. 1, 2
Age-Stratified Differential Diagnosis
Patients Over 35-40 Years (Most Common Presentations)
Rotator cuff disorders are the leading cause, accounting for approximately 10% of all shoulder pain presentations and representing the most frequent pathology in this age group 1, 3:
- Full-thickness rotator cuff tears
- Partial-thickness tears (bursal-sided or articular-sided)
- Rotator cuff tendinopathy/tendinitis
Adhesive capsulitis (frozen shoulder) accounts for approximately 6% of shoulder pain cases and presents with progressive loss of both active and passive range of motion 3
Glenohumeral osteoarthritis represents 2-5% of shoulder pain presentations and increases in prevalence with advancing age 3
Subacromial impingement syndrome with associated subacromial-subdeltoid bursitis is extremely common in this population 4, 5
Calcific tendinosis should be considered, particularly when pain is severe and acute in onset 5
Patients Under 35 Years
Glenohumeral instability (anterior, posterior, or multidirectional) is the predominant concern in younger adults 2
Labral tears including superior labral anterior-to-posterior (SLAP) lesions are more common in this age group, particularly in athletes 6, 2
Additional Differential Considerations (All Ages)
Acromioclavicular joint pathology including osteoarthritis or osteolysis presents with superior shoulder pain localized to the AC joint 2, 5
Biceps tendinopathy or long head of biceps tendinosis causes anterior shoulder pain 5
Referred pain from cervical spine including cervical radiculopathy must be excluded, particularly when pain radiates down the arm with neurological symptoms 2
Septic arthritis is a critical red flag diagnosis requiring immediate specialist referral, particularly in patients with fever, chills, or constitutional symptoms 1, 2
Avascular necrosis of the humeral head should be considered, especially in patients with risk factors (corticosteroid use, alcohol abuse, sickle cell disease) 3
Occult fractures can occur with minimal or unrecognized trauma, particularly in elderly patients with osteoporosis 1, 2
Pain Location as Diagnostic Clue
Anterior shoulder pain suggests rotator cuff pathology (particularly subscapularis) or biceps tendon disease 2
Superior shoulder pain indicates acromioclavicular joint pathology 2
Scapular region pain may represent referred pain from cervical spine or rotator cuff disease 2
Critical Pitfall to Avoid
Do not assume absence of trauma means absence of fracture, especially in elderly patients where osteoporotic fractures can occur with minimal or unrecognized trauma that patients may not recall or consider significant 1, 2. This is why standard radiography remains mandatory as the first imaging study even in "non-traumatic" presentations 1, 7.
Diagnostic Approach
Standard radiography with at least three views (AP in internal and external rotation, plus axillary or scapular Y view) is mandatory as the initial imaging study to exclude fractures, dislocations, arthritis, and calcific deposits 1, 7, 2
Clinical examination alone is generally insufficient for pathoanatomical diagnosis, as single clinical tests lack adequate sensitivity and specificity, and a combination of history, examination findings, and imaging is required 4, 8