What is the cause of right shoulder and arm pain and tingling in an adult with a history of physical activity or repetitive strain, possibly related to cervical radiculopathy or thoracic outlet syndrome?

Right Shoulder and Arm Pain with Tingling: Diagnostic Approach

Cervical radiculopathy is the most likely diagnosis and should be your primary consideration, as nerve root compression in the cervical spine commonly presents with shoulder and arm pain accompanied by tingling, particularly in adults with repetitive strain history. 1, 2

Primary Differential Diagnoses

Cervical Radiculopathy (Most Likely)

• Cervical radiculopathy results from herniated discs or osteophytes causing nerve root compression, leading to neuropathic pain radiating from the neck into the shoulder and arm with characteristic tingling and numbness. 2
• The annual incidence is 83 per 100,000 persons, making this a common cause of your patient's presentation. 1
• Hallmark symptoms include numbness, tingling, weakness, or radiation of pain down the arm in specific dermatomal distributions (C5, C6, C7, or C8). 2
• Document the exact radiation pattern to determine which cervical nerve root is affected. 2

Thoracic Outlet Syndrome (Important Alternative)

• Neurogenic TOS presents with chronic arm and hand paresthesia, numbness, or weakness due to brachial plexus compression at the superior thoracic outlet. 3, 4
• This occurs with compression between the anterior and middle scalene muscles, through the costoclavicular triangle, or at the pectoralis minor space. 3
• Repetitive upper-extremity movement (swimming, throwing, overhead activities) is a key risk factor. 3
• Symptoms worsen with shoulder abduction and overhead positioning. 5
• Bilateral cervical ribs are present in 0.56% of the population and can cause TOS that mimics cervical radiculopathy. 5

Rotator Cuff Pathology with Referred Pain

• In patients over 35-40 years, rotator cuff disease is a predominant cause of chronic shoulder pain. 2, 6
• Anterior shoulder pain specifically suggests rotator cuff or biceps tendon pathology. 2
• However, isolated rotator cuff pathology typically does NOT cause tingling or numbness—these neurological symptoms point toward nerve involvement. 6
• Rotator cuff tears can refer pain to the scapular region but would not explain arm tingling. 1

Critical Diagnostic Steps

Clinical Examination Priorities

• Test for dermatomal sensory changes, weakness in specific muscle groups, and diminished reflexes to localize the cervical nerve root level. 2
• Assess for allodynia or hyperpathia suggesting neuropathic pain. 2
• Perform provocative maneuvers: Spurling's test for cervical radiculopathy, Adson's test and elevated arm stress test for TOS. 3
• Evaluate shoulder range of motion and impingement signs to assess for concurrent rotator cuff pathology. 2

Imaging Strategy

• Order MRI of the cervical spine without contrast as the preferred initial advanced imaging when clinical examination supports radiculopathy. 2
• MRI directly visualizes disc herniations, osteophytes, and nerve root compression with sensitivity over 80% and specificity of 95%. 2
• Plain radiographs of the cervical spine may be obtained first to assess for gross structural abnormalities, degenerative changes, cervical ribs, or alignment issues. 2, 5
• Do not assume this is "muscle tension" or "muscle spasm" without ruling out structural cervical spine pathology. 2
• MRI of the brachial plexus should be considered if TOS is suspected, particularly with negative cervical spine imaging. 3

Electrodiagnostic Testing

• Consider electrodiagnostic testing if imaging is negative or equivocal, with sensitivity over 80% for confirming nerve compression and localizing the level. 2

Management Algorithm

If Cervical Radiculopathy is Confirmed:

• Continue or initiate pregabalin 300-600 mg daily in divided doses for neuropathic pain management. 2
• Alternative nerve-stabilizing agents include gabapentin or duloxetine. 2
• Consider botulinum toxin type A injections into affected muscles for cervical dystonia or muscle spasms. 2
• Most cases can be managed conservatively with physical therapy focusing on cervical stabilization and nerve gliding exercises. 1

If Thoracic Outlet Syndrome is Confirmed:

• Initial conservative management includes physical therapy with postural correction and scalene muscle stretching. 3
• Surgical decompression (first rib and anterior scalene resection via transaxillary approach) is indicated if conservative treatment fails after 3-6 months. 4, 5
• Complete resolution of symptoms typically occurs within 5-12 months post-operatively. 5

If Concurrent Rotator Cuff Pathology:

• Refer to rehabilitation specialist for comprehensive management. 2
• Most rotator cuff pathology can initially be managed conservatively without surgical intervention. 2, 6

Critical Pitfalls to Avoid

• Never delay imaging if red flags are present (progressive neurological deficits, severe unrelenting pain, constitutional symptoms). 2
• Spondylotic changes on imaging are common in patients over 30 years and correlate poorly with the presence of neck pain—clinical correlation is essential. 1
• MRI findings of disc degeneration occur in 53.9% of asymptomatic patients, so abnormal imaging does not always correlate with symptom severity. 1
• Arteriogenic TOS can present identically to cervical radiculopathy—maintain suspicion to avoid inappropriate cervical spine surgery. 7
• Trigger points in infraspinatus and teres minor can rarely reproduce upper extremity numbness and tingling, but this is a diagnosis of exclusion after ruling out neural compression. 8