What is the appropriate diagnosis and treatment for a patient experiencing lateral right pain radiating to the shoulder and fingers?

Lateral Right Shoulder Pain Radiating to Fingers: Diagnosis and Management

This presentation suggests cervical radiculopathy or brachial plexus compression rather than primary shoulder pathology, and requires cervical spine evaluation in addition to standard shoulder imaging. 1, 2, 3

Diagnostic Approach

Initial Red Flag Assessment

• Immediately evaluate for cardiac, pulmonary, or subdiaphragmatic pathology if the patient has fever, acute neurologic deficits below the elbow, or systemic symptoms, as these can refer pain to the shoulder through the phrenic nerve 1, 2
• Radiating pain to the fingers with motor or sensory changes strongly indicates neurologic etiology rather than intrinsic shoulder disease 3

First-Line Imaging

• Obtain standard shoulder radiographs (AP, Grashey, and axillary or scapular Y views) as the initial study to rule out fracture, dislocation, or glenohumeral pathology 1, 4
• Simultaneously order cervical spine radiographs given the radiation pattern to the fingers, which suggests nerve root or brachial plexus involvement 2, 3

Advanced Imaging Algorithm

If radiographs are noncontributory:

• Order MRI of the cervical spine without contrast as the primary study when pain radiates below the elbow with sensory or motor changes, to evaluate for disc herniation, foraminal stenosis, or spinal cord pathology 3
• Order MRI of the shoulder without contrast to evaluate for rotator cuff pathology, nerve compression at the thoracic outlet, or soft tissue causes of brachial plexus irritation 1, 5
• Consider nerve conduction studies to localize peripheral nerve involvement if MRI findings are equivocal 2

Differential Diagnosis by Anatomic Location

Cervical Spine Origin

• Extruded intervertebral discs, foraminal root compression, or spinal cord tumors present with radiating pain and motor/sensory deficits below the elbow 3
• Myelography or discography may be required for precise identification if standard MRI is inconclusive 3

Thoracic Outlet Compression

• Brachial plexus compression or subclavian vessel occlusion from thoracic outlet narrowing, scalene muscle syndrome, cervical rib, or first rib abnormalities 2, 3
• Diagnosed primarily through history, physical examination, and specific provocative test maneuvers 2

Peripheral Nerve Compression

• Radial tunnel syndrome presents with lateral elbow and dorsal forearm pain radiating to the wrist and dorsum of fingers, most common in women aged 30-50 years 6
• Compression occurs from the radial head to the inferior border of the supinator muscle, with the arcade of Frohse being the most common site 6
• Clinical examination (rule of nine test, weakness of third finger and wrist extension) is more important than electrodiagnostic testing 6

Intrinsic Shoulder Pathology

• For patients over 35 years, rotator cuff disease predominates with pain during overhead activities, night pain, and weakness with external rotation or abduction 1
• For patients under 35 years, labral tears and instability are more common, with recurrent subluxation or "dead arm" sensation 1

Treatment Algorithm

Conservative Management (First-Line)

• NSAIDs: ibuprofen 400-800 mg three to four times daily 1
• Neuromodulating medications (gabapentin or pregabalin) when sensory changes, allodynia, or electric shock-like pain are present 1, 5
• Structured exercise program to strengthen the shoulder girdle for thoracic outlet compression 2
• Activity modification avoiding repetitive overhead movements and provocative positions 1, 5

Interventional Options After Failed Conservative Management

• Suprascapular nerve blocks or botulinum toxin injections 1
• Corticosteroid injections (limited evidence) 1
• Ultrasound or fluoroscopy-guided arthrocentesis if septic arthritis is suspected 1, 7

Surgical Referral Indications

• Persistent neurologic deficits 3, 7
• Failed adequate conservative management (typically 3-6 months) 1
• Thoracic outlet syndrome not responding to shoulder girdle strengthening exercises may require first rib excision 2
• Radial tunnel syndrome surgery can diminish pain in 67-93% of patients 6
• Unstable or significantly displaced fractures 1, 7

Critical Pitfalls to Avoid

• Do not dismiss radiation to the fingers as typical shoulder pain—this pattern mandates cervical spine and peripheral nerve evaluation 2, 3
• Do not rely solely on shoulder imaging when symptoms extend below the elbow, as the shoulder joint may be a secondary irritant rather than the primary pathology 3
• Do not order MR arthrography as the initial advanced imaging study when neurologic symptoms are present; standard MRI without contrast is appropriate 1, 5
• Do not attribute all lateral arm pain to rotator cuff disease without considering radial tunnel syndrome, especially in women aged 30-50 years with dorsal forearm and finger involvement 6