In a 42-year-old female with a one-month history of intermittent left-sided neck and shoulder pain, stiffness, radiating tingling down the left arm, positive Spurling, Hawkins, and O'Brien tests, and no motor weakness, what are the top three differential diagnoses and the reasoning for each?

Top 3 Differential Diagnoses

The most likely diagnosis is cervical radiculopathy at C5-C6 or C6-C7, followed by concurrent shoulder impingement syndrome (supraspinatus tendinopathy/labral pathology), with myofascial neck pain as a third consideration.

1. Cervical Radiculopathy (Most Likely)

This is the primary diagnosis given the constellation of findings.

Supporting Evidence:

• Positive Spurling test - This is highly specific (0.84-1.00) for cervical radiculopathy, though sensitivity is moderate (0.38-0.98) 1, 2, 3. The 2025 ACR guidelines emphasize that cervical radiculopathy presents with upper limb pain or sensorimotor deficit secondary to nerve root compression 1
• Radicular pattern: Pain radiating from neck down the left arm with tingling is classic for nerve root irritation 1, 4
• Reproduction with side bending toward the painful side: This maneuver increases foraminal narrowing and reproduces radicular symptoms
• Osteopathic findings: C5 extended, rotated left, sidebent left (C5 E RL SL) directly correlates with potential C5-C6 nerve root compression
• Functional deficits: Difficulty holding objects and occasional dropping suggests motor involvement, though formal strength testing was 5/5 (may indicate early or intermittent nerve compromise)

Clinical Reasoning:

The C5-C6 or C6-C7 nerve roots are most commonly affected in cervical radiculopathy 4. While 75-90% of cases resolve with conservative therapy 1, the one-month duration places this in the subacute category requiring attention. Important caveat: Physical examination has limited diagnostic accuracy for cervical radiculopathy when used alone 1, and MRI findings must be correlated with clinical symptoms due to high false-positive rates in asymptomatic patients 1.

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2. Shoulder Impingement Syndrome with Supraspinatus Tendinopathy/Labral Pathology

The positive shoulder-specific tests indicate concurrent shoulder pathology that may be contributing to or mimicking cervical symptoms.

Supporting Evidence:

• Positive Hawkins test: Indicates subacromial impingement
• Positive O'Brien's active compression test: Suggests superior labral pathology (SLAP lesion) or acromioclavicular joint involvement
• Painful shoulder ROM: Forward flexion to 90° with internal rotation and resisted forward flexion in adduction with internal rotation
• Osteopathic findings: Tender point at left supraspinatus with tissue texture changes directly implicates rotator cuff pathology
• Prior cortisone injection: History of left shoulder injection one year ago suggests pre-existing shoulder pathology

Clinical Reasoning:

Critical diagnostic challenge: Shoulder impingement can present as neck pain 5. In one study, 30 of 34 patients with neck pain near the superomedial scapula had relief after subacromial injection, confirming referred pain from shoulder impingement 5. The combination of positive cervical AND shoulder tests suggests dual pathology - both conditions can coexist and complicate each other 6, 7. The negative Empty Can and Bear Hug tests argue against complete rotator cuff tear but don't exclude partial tears or tendinopathy.

Distinguishing Features:

• Cervical radiculopathy typically causes pain that radiates distally along a dermatomal pattern
• Shoulder pathology causes pain localized to the shoulder with possible referral to the neck/scapular region
• This patient has BOTH patterns, suggesting concurrent pathology

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3. Myofascial Pain Syndrome with Cervical Muscle Strain

Occupational ergonomic factors and muscle dysfunction contribute to this diagnosis.

Supporting Evidence:

• Occupational aggravation: Administrative assistant with desk positioning that provokes symptoms
• Positional aggravation: Certain sleeping positions worsen pain
• Osteopathic findings: Cervical region demonstrated greatest restriction; T1 dysfunction and left ribs 1-3 inhalation dysfunction suggest biomechanical dysfunction
• Muscle spasm noted on exam: Common finding in myofascial pain
• Tension headaches: Associated symptom consistent with cervical muscle tension

Clinical Reasoning:

While myofascial pain alone doesn't explain the radicular symptoms or positive Spurling test, it likely represents a contributing factor that exacerbates the underlying cervical radiculopathy. The ACR guidelines note that mechanical pain from spine supporting structures is common in cervical pain presentations 1. The ergonomic factors and muscle dysfunction may be perpetuating the nerve root irritation through altered cervical mechanics.

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Key Diagnostic Pitfalls to Avoid:

1. Don't rely on imaging alone: MRI has high false-positive rates in asymptomatic patients 1. Diagnosis requires clinical correlation
2. Don't miss dual pathology: Cervical and shoulder conditions frequently coexist and can be confused 6, 7, 5
3. Don't overlook red flags: This patient has a history of Non-Hodgkin lymphoma - while no current red flags are present, maintain vigilance for recurrence presenting as neck pain 1
4. Don't assume normal strength testing excludes radiculopathy: Intermittent dropping of objects with 5/5 strength may indicate early motor involvement or functional weakness from pain inhibition

Recommended Diagnostic Approach:

Initial management should include:

• Conservative therapy (physical therapy, NSAIDs, ergonomic modifications) as 75-90% of cervical radiculopathy resolves nonoperatively 1, 4
• If symptoms persist beyond 4-6 weeks, obtain MRI cervical spine without contrast to evaluate for nerve root compression 1, 4
• Consider diagnostic subacromial injection to differentiate shoulder-referred neck pain from primary cervical pathology 5
• Electrodiagnostic testing if diagnosis remains unclear or peripheral neuropathy is suspected 4