Diagnostic Approach to Shoulder Pain

Primary Differential Diagnoses by Age and Presentation

The American College of Radiology recommends radiography as the initial imaging modality for all presentations of shoulder pain, with a minimum of 3 views including AP, Grashey, and axillary or scapular Y projections 1, 2
For traumatic presentations, fractures such as proximal humerus, clavicle, or scapular fractures should be evaluated with standard radiographic series including AP, Grashey, and axillary or scapular Y views 1, 2
Glenohumeral dislocation/instability is most common in younger patients and requires orthogonal radiographic views to confirm, with a focus on identifying Hill-Sachs deformity or bony Bankart lesions 1, 2
Acromioclavicular joint injury should be assessed with dedicated AC joint views 1
For patients under 35 years, labral tears and instability predominate, and suspicion should be raised when history includes recurrent subluxation, "dead arm" sensation, or mechanical symptoms 3, 4, 2
For patients 35 years and older, rotator cuff disease becomes the primary concern, with symptoms including pain with overhead activities, night pain, weakness with external rotation or abduction 3, 4, 5
Biceps tendon pathology should be considered in patients with pain in the anterior shoulder and positive Speed's or Yergason's test 4

The initial evaluation should include obtaining radiographs first for all patients, with identification of red flags requiring urgent referral, such as fever with joint effusion, acute neurologic deficits, or suspected cardiac/pulmonary pathology 1, 2, 3, 4
If radiographs show a fracture, CT without contrast should be ordered to characterize fracture complexity, displacement, and surgical planning 2, 5
For suspected instability/dislocation, MRI without IV contrast is the primary study, with CT without contrast considered when bone loss assessment is critical 2, 5
For suspected labral tear, MR arthrography is the reference standard in subacute/chronic settings, while MRI without contrast is preferred in acute trauma due to hemarthrosis providing joint distention 3, 4, 2
For suspected rotator cuff tear, MRI without contrast or ultrasound are equivalent first-line studies, with choice depending on local expertise 3, 4, 5
For suspected septic arthritis, ultrasound-guided or fluoroscopy-guided arthrocentesis is the procedure of choice, with imaging used for guidance rather than diagnosis 3, 4

Conservative management is the first-line approach for most non-urgent pathology, with NSAIDs such as ibuprofen 400-800 mg three to four times daily, structured exercise programs, and patient education on positioning, ergonomics, and activity modification 6
Neuromodulating medications such as gabapentin or pregabalin may be considered when sensory changes, allodynia, or hyperpathia are present 7, 6
Interventional options after failed conservative management include suprascapular nerve blocks, botulinum toxin injections, and corticosteroid injections, with limited evidence for the latter 7, 6
Surgical referral indications include acute fractures requiring fixation, failed adequate conservative management, progressive neurological deficits, and severe restrictions in range of motion with muscle contractures 2, 5, 6, 7