In a 73-year-old woman with a one-month history of numbness and tingling in the right middle and ring fingers radiating to the shoulder and right scapular tenderness, what investigations should be ordered?

Diagnostic Workup for Numbness and Tingling in Right Middle and Ring Fingers with Radiation to Shoulder

Order nerve conduction studies/EMG first to distinguish between cervical radiculopathy (C7 nerve root) and ulnar neuropathy at the elbow, followed by MRI of the cervical spine if radiculopathy is suspected or if symptoms persist despite normal electrodiagnostic studies. 1, 2

Initial Clinical Assessment

Key Physical Examination Findings to Document

• Sensory distribution mapping: Middle and ring finger involvement suggests either C7 radiculopathy or ulnar nerve pathology, though classic ulnar neuropathy typically affects ring and small fingers 2, 3
• Deep tendon reflexes: Diminished triceps reflex is the most common neurologic finding in cervical radiculopathy and would support C7 root involvement 2
• Motor strength testing: Assess triceps strength (C7), finger extension, and intrinsic hand muscles to differentiate radiculopathy from peripheral nerve compression 2, 3
• Provocative maneuvers:
  • Spurling test (neck extension with rotation and axial compression toward symptomatic side) to confirm cervical radiculopathy 2
  • Shoulder abduction test (relief of symptoms with arm abduction) suggests nerve root compression 2
  • Upper limb tension test for neural tension 2
• Scapular tenderness: May indicate referred pain from cervical spine pathology or myofascial component 2

Critical Red Flags Requiring Urgent Imaging

• Progressive motor weakness
• Myelopathic signs (gait instability, hyperreflexia, Babinski sign)
• History of malignancy
• Constitutional symptoms (fever, weight loss)
• Trauma history 2, 4

Diagnostic Algorithm

Step 1: Electrodiagnostic Testing (First-Line)

Nerve conduction studies and EMG are the initial diagnostic test of choice when the clinical diagnosis is unclear or when peripheral neuropathy is a likely alternative diagnosis. 2, 3

• Rationale: Electrodiagnostic testing distinguishes between:

  • Cervical radiculopathy (C7 nerve root compression)
  • Ulnar neuropathy at the elbow or wrist
  • Brachial plexopathy
  • Polyneuropathy 5, 2

• Expected findings in cervical radiculopathy: Denervation in C7-innervated muscles (triceps, wrist extensors, finger extensors) with normal sensory nerve conduction studies, as radiculopathy affects the nerve root proximal to the dorsal root ganglion 2, 3

• Expected findings in ulnar neuropathy: Slowed conduction velocity across the elbow or abnormal sensory nerve action potentials in ulnar distribution 3

Step 2: MRI Cervical Spine (If Radiculopathy Suspected or Persistent Symptoms)

MRI cervical spine without and with contrast is indicated if:

• Electrodiagnostic studies confirm radiculopathy
• Symptoms persist after 4-6 weeks of conservative treatment
• Red flag symptoms are present
• Clinical examination strongly suggests radiculopathy but confirmation is needed for treatment planning 2, 4

Important caveat: Imaging is NOT required initially unless red flags are present, as degenerative changes are ubiquitous and must correlate with clinical symptoms for meaningful diagnosis 2, 4

Step 3: Consider Brachial Plexus Imaging (If Atypical Features)

MRI of the brachial plexus without and with contrast should be considered if:

• Electrodiagnostic studies suggest plexopathy rather than radiculopathy or peripheral nerve compression
• Scapular pain is prominent with multiple nerve territory involvement
• Symptoms don't fit typical radiculopathy or peripheral nerve patterns 1

Key distinction: Dedicated brachial plexus imaging differs from standard neck or chest MRI and requires orthogonal views through the oblique planes of the plexus with T1, T2, fat-saturated T2, and fat-saturated T1 post-contrast sequences 1

Alternative Diagnoses to Consider

Thoracic Outlet Syndrome (Neurogenic Type)

Consider if:

• Symptoms worsen with arm elevation or specific positions
• Involvement of C8-T1 distribution (though your patient has C7 pattern)
• Scapular pain with neurovascular bundle compression 1, 6

Diagnostic approach: MRI chest without contrast can evaluate the costoclavicular and interscalene spaces, though this is less likely given the C7 distribution 1

Cervical Spondylosis vs. Disc Herniation

Both are common causes of cervical radiculopathy in this age group (most prevalent 50-54 years) 2, 4

• Natural history: 75-90% of cervical radiculopathy cases resolve with conservative treatment regardless of etiology 2, 4
• Imaging timing: Reserve MRI for surgical planning or persistent symptoms after 4-6 weeks of conservative care 2, 4

Common Pitfalls to Avoid

1. Ordering MRI cervical spine first without electrodiagnostic testing: This misses peripheral nerve pathology (ulnar neuropathy) which requires different management 2, 3

2. Assuming all degenerative changes on MRI are clinically significant: Degenerative findings are extremely common and must correlate with clinical presentation and electrodiagnostic findings 2, 4

3. Confusing cervical radiculopathy with peripheral nerve entrapment: Both can coexist ("double crush syndrome"), making electrodiagnostic testing essential for accurate localization 3

4. Ordering standard MRI neck instead of dedicated brachial plexus imaging when plexopathy is suspected: Standard sequences miss plexus pathology 1

5. Not documenting deep tendon reflexes carefully: Diminished triceps reflex is the most reliable objective finding in C7 radiculopathy 2

Initial Management While Awaiting Diagnostic Studies

• Reassure patient that most cases resolve with conservative treatment 2, 4
• NSAIDs for pain control 2, 4
• Avoid immobilization beyond brief periods; gentle range of motion is preferred 4
• Physical therapy referral can be initiated while awaiting electrodiagnostic studies 2, 4