What are the differentials, diagnostics, and management for a patient presenting with neck pain and left shoulder pain?

Differential Diagnosis and Diagnostic Approach for Neck Pain and Left Shoulder Pain

The most critical initial step is to rule out life-threatening cardiac and vascular causes, particularly acute coronary syndrome, as atypical presentations of myocardial infarction commonly include pain radiating to the neck, jaw, and left shoulder, especially in women and elderly patients. 1

Immediate Life-Threatening Differentials to Exclude

Cardiac Causes

• Acute coronary syndrome (unstable angina/NSTEMI/STEMI) can present with pain in the neck, shoulder, or arm rather than typical chest pain 1
• Women and elderly patients particularly present atypically with dyspnea, nausea, diaphoresis, or isolated neck/shoulder pain 1
• Obtain 12-lead ECG immediately at first medical contact; ST-segment depression as little as 0.05 mV predicts adverse outcomes 1
• Draw cardiac biomarkers (troponin, CK-MB) and two sets of blood cultures 1

Other Emergent Causes

• Aortic dissection - assess for sudden onset, tearing quality, radiation to interscapular region 1
• Pulmonary embolism - consider with dyspnea, pleuritic pain, risk factors 1
• Vertebral osteomyelitis - suspect with fever, elevated ESR/CRP, recent bacteremia (especially S. aureus) 1
• Splenic pathology - left shoulder pain can represent referred pain from splenic rupture or infarction 2

Red Flag Assessment

Obtain ESR and CRP immediately; elevated inflammatory markers combined with neck pain constitute red flags requiring urgent MRI evaluation. 1, 3

Red Flags Requiring Urgent Investigation

• Fever with neck pain (consider vertebral osteomyelitis, meningitis) 1, 4
• Elevated ESR or CRP 1, 3
• Recent bloodstream infection (especially S. aureus, S. lugdunensis, Brucella) 1
• New neurologic symptoms or deficits 1
• Constitutional symptoms (weight loss, night sweats, fatigue) 1
• History of malignancy or immunosuppression 1
• Recent swollen lymph nodes with dysphagia 3
• Minimal response to NSAIDs 3

Diagnostic Algorithm by Clinical Presentation

For Patients WITH Red Flags

Order MRI cervical spine without contrast as the primary imaging modality when red flags are present. 1, 3

• MRI superior for detecting soft tissue abnormalities, infection, inflammation, and malignancy 1, 3
• If S. aureus bacteremia within 3 months and compatible MRI changes present, disc space aspiration may be unnecessary 1
• Perform image-guided aspiration biopsy when microbiologic diagnosis not established by blood cultures 1
• Do NOT perform aspiration if S. aureus, S. lugdunensis, or Brucella already identified in blood 1

For Patients WITHOUT Red Flags (Mechanical Neck/Shoulder Pain)

Begin with plain radiographs (AP internal/external rotation and axillary or scapula-Y views) as the initial imaging for traumatic or acute presentations. 1

Grading System for Non-Traumatic Neck Pain 5

• Grade I: No major pathology, minimal interference with activities - consider conservative management
• Grade II: No major pathology, significant interference with activities - offer multimodal treatment
• Grade III: Neurologic signs of nerve compression - may require advanced imaging and specialist referral
• Grade IV: Signs of major pathology - requires specific management

Initial Imaging Approach

• Radiographs are appropriate first-line for suspected fracture, dislocation, or gross malalignment 1
• Axillary or scapula-Y views essential; AC and glenohumeral dislocations missed on AP views alone 1
• CT without contrast indicated when radiographs indeterminate for fracture characterization or subtle nondisplaced fractures 1
• MRI without contrast reserved for suspected rotator cuff tears, labral pathology, or when radiculopathy present 1

Musculoskeletal Differentials

Cervical Spine Pathology

• Degenerative disc disease (present in 53.9% of adults, increases with age but poorly correlates with symptoms) 1
• Cervical radiculopathy (annual incidence 83 per 100,000; 75-90% resolve with conservative therapy) 1
• Acute calcific tendinitis of longus colli muscle (presents with fever, neck stiffness, prevertebral edema on CT) 4
• Facet joint arthropathy 1

Shoulder Pathology

• Shoulder impingement can present as isolated neck pain near superomedial scapula 6
• Positive impingement sign with neck pain referral, relief after subacromial lidocaine/cortisone injection diagnostic 6
• Rotator cuff tears (traumatic massive tears may require expedited repair for optimal outcomes) 1
• Acromioclavicular separation 1
• Glenohumeral instability/dislocation 1

Critical Diagnostic Pitfalls

• Do NOT rely on nitroglycerin response to exclude cardiac ischemia; obtain repeat ECG if symptoms improve 1
• Do NOT assume degenerative changes explain symptoms; these are common in asymptomatic individuals 1, 3
• Do NOT order routine imaging for mechanical neck pain without red flags or radiculopathy 1
• Consider pulmonary pathology when shoulder pain accompanied by cough, dyspnea, fever, or effort-related symptoms 7
• Physical examination alone has limited accuracy for diagnosing cervical radiculopathy; always correlate imaging with clinical findings 1

Management Based on Findings

Conservative Management (Grade I-II, No Red Flags) 1, 5

• Exercises and mobilization provide short-term relief 1, 5
• Manual therapy only as component of multimodal care, never standalone 1
• NSAIDs for shortest period possible 1
• Avoid opioids unless carefully weighing risks/benefits 1

Surgical Consideration 1

• Offer evidence-based non-surgical care minimum 3 months before surgical referral (except unstable fractures, joint instability) 1
• Grade III with severe persistent radicular symptoms may benefit from corticosteroid injections or surgery 5

Follow-up for Red Flag Cases 3

• If MRI negative for serious pathology, continue conservative management and repeat CRP in 2-4 weeks 3
• If MRI reveals significant pathology, refer to appropriate specialist 3