What could be causing my left shoulder pain with occasional numbness for the past year?

Chronic Left Shoulder Pain with Numbness: Diagnostic and Management Approach

You need advanced imaging with MRI without contrast or ultrasound (if local expertise available) to evaluate for rotator cuff disease, which is the most likely diagnosis given your age and chronic symptoms, combined with cervical spine evaluation to rule out nerve compression causing the numbness. 1, 2

Most Likely Diagnoses Based on Your Presentation

Primary Consideration: Rotator Cuff Pathology

• Rotator cuff tendinopathy or tear is the predominant cause of shoulder pain in patients over 35-40 years, presenting with pain during overhead activities and weakness 2, 3
• The chronic one-year duration strongly suggests degenerative rotator cuff disease rather than acute injury 2, 4
• Pain typically occurs during activities requiring shoulder elevation or rotation 2

Secondary Consideration: Cervical Radiculopathy

• The numbness component suggests possible cervical spine pathology with nerve compression, which commonly refers pain to the shoulder 2, 3, 5
• Cervical radiculopathy can mimic shoulder pathology and must be differentiated 1, 5
• Recent evidence shows that carpal tunnel syndrome and cubital tunnel syndrome can present as "idiopathic" shoulder pain with numbness, though this is less common 6

Immediate Diagnostic Steps

Initial Imaging (Mandatory First Step)

• Start with standard shoulder radiographs including AP views in internal and external rotation, plus axillary lateral or scapular Y view 4
• Plain films effectively demonstrate fractures, arthritis, and shoulder malalignment even without recalled trauma 4
• Do not skip this step even without trauma history—osteoporotic or stress fractures can occur with minimal trauma 4

Advanced Imaging (Next Step)

Three equally appropriate options based on local expertise: 1

• MRI shoulder without contrast (Rating 9/9): Best for evaluating rotator cuff tears, labral pathology, and occult fractures 1, 4
• MR arthrography (Rating 9/9): Particularly useful if you're under 35 years, though less likely given chronic presentation 1
• Ultrasound (Rating 9/9): Excellent for rotator cuff and biceps tendon evaluation if experienced operator available 1, 4

Cervical Spine Evaluation

• Obtain cervical spine imaging if numbness persists or radiates down the arm, as this suggests nerve root compression 2, 5
• Physical examination should include thorough sensorimotor testing of the upper extremity 7

Management Algorithm

Conservative Treatment (First-Line)

Start immediately while awaiting imaging results: 4, 8

• Acetaminophen up to 4 grams daily as first-line pain control 4
• Topical NSAIDs (methyl salicylate, capsaicin, or menthol) for additional relief without systemic toxicity 4
• Avoid overhead activities that aggravate symptoms 2

Physical Therapy Protocol

Begin structured rehabilitation: 4

• Range of motion exercises focusing on external rotation and abduction 4
• Avoid overhead pulleys, which may worsen rotator cuff pain 4
• Scapular stabilization exercises to address potential dyskinesis 2
• Perform stretching and mobilization several times daily 4

Escalation if Conservative Treatment Fails

After 4-6 weeks without improvement: 4, 8

• Consider intraarticular glucocorticoid injection if evidence of inflammation 4
• Trial of oral NSAIDs if acetaminophen inadequate, but use cautiously and short-term given GI/renal risks 4
• Nerve blocks under ultrasound guidance if peripheral nerve compression suspected (median/ulnar nerves) 6

Red Flags Requiring Urgent Specialist Referral

Immediate orthopedic consultation if: 4

• Progressive neurological deficits (weakness, sensory loss) 4
• Fever, chills, or constitutional symptoms suggesting septic arthritis 1, 3
• Unstable or displaced fractures on imaging 4
• Suspected massive rotator cuff tear requiring expedited repair 4
• Shoulder instability with recurrent subluxation/dislocation 4, 3

Critical Pitfalls to Avoid

• Do not assume absence of trauma means no structural damage—chronic degenerative tears and stress fractures occur without acute injury 4
• Do not ignore the numbness component—this may indicate cervical radiculopathy requiring separate evaluation 2, 5
• Do not use NSAIDs long-term without gastroprotection, especially if over 60 years 4
• Do not delay imaging beyond 6-8 weeks if conservative treatment fails—chronic rotator cuff tears may become irreparable 8

Age-Specific Considerations

• If you're over 35-40 years: Focus is on rotator cuff disease and degenerative changes as primary pathology 1, 2, 3
• If you're under 35 years: Consider labral tears and instability, warranting MR arthrography 1, 3