In a young adult presenting with neck pain and unilateral brachialgia, abnormal ipsilateral F‑wave responses, and a normal cervical MRI, what is the most likely diagnosis and recommended initial management?

Clinical Presentation Drives Diagnosis: Cervical Radiculopathy

You are absolutely correct—the clinical presentation of neck pain with unilateral brachialgia is the cornerstone of diagnosis here, and this patient most likely has cervical radiculopathy that requires repeat or advanced imaging despite the reportedly "normal" MRI. The abnormal F-wave is a supportive finding but should not overshadow the classic clinical syndrome.

Why the Clinical Picture Takes Priority

The combination of neck pain with unilateral arm pain radiating in a dermatomal distribution is the hallmark presentation of cervical radiculopathy 1, 2. This clinical syndrome occurs when a cervical nerve root is compressed, most commonly by disc herniation or osteophyte formation 3. The diagnosis of cervical radiculopathy is fundamentally clinical, and imaging serves to confirm the anatomic correlate of the clinical findings, not to make the diagnosis in isolation 4.

The Problem with "Normal" MRI

Here's the critical issue: MRI frequently shows false-negative results in cervical radiculopathy, and abnormal levels on MRI do not always correspond to the clinical examination level 4. The guidelines explicitly acknowledge that:

• MRI is frequently positive in asymptomatic patients
• Detected abnormalities are not always associated with acute symptoms
• Abnormal levels on imaging may not match the clinical-physical examination findings 4

This means a "normal" MRI does not exclude cervical radiculopathy when the clinical presentation is compelling. The imaging may have missed subtle foraminal stenosis, a small lateral disc herniation, or the study may not have adequately visualized the specific level causing symptoms.

Recommended Diagnostic Approach

Immediate Steps:

1. Repeat MRI cervical spine without IV contrast with specific attention to:

   • Neural foramina at the symptomatic level
   • Oblique sequences if not already obtained
   • Ensure adequate visualization of the clinically suspected level 4

2. Consider CT myelography if repeat MRI is non-diagnostic:

   • CT myelography offers higher spatial resolution than MRI
   • Provides excellent depiction of nerve roots and foraminal anatomy
   • Particularly useful when MRI findings don't correlate with clinical presentation 4

Clinical Correlation Requirements:

Match the imaging findings to:

• Specific dermatomal pain pattern
• Sensory deficits in the affected dermatome
• Motor weakness in the myotomal distribution
• Reflex changes corresponding to the nerve root level
• Provocative maneuvers (Spurling's test, upper limb tension tests)

Initial Management Algorithm

For cervical radiculopathy with chronic symptoms (>12 weeks) and no red flags, MRI cervical spine without IV contrast is the appropriate first imaging modality 4. However, when initial imaging is negative but clinical suspicion remains high:

Conservative Management (First-Line):

1. Supervised exercise therapy and manual therapy 5
2. NSAIDs (oral or topical) after careful consideration 5
3. Short-term cervical collar use for immobilization 3
4. Physical therapy with multimodal approach 3
5. Consider selective nerve root blocks for both diagnostic and therapeutic purposes 3

Indications for Surgical Referral:

• Progressive neurologic deficit
• Failure of 6-12 weeks of conservative management
• Significant motor weakness
• Myelopathic signs suggesting cord compression 2

Critical Pitfalls to Avoid

The most dangerous pitfall here is dismissing the clinical diagnosis because of negative imaging. The F-wave abnormality actually supports nerve root dysfunction and should reinforce—not distract from—the clinical diagnosis of radiculopathy. F-waves assess proximal nerve conduction and can be abnormal in radiculopathy even when routine nerve conduction studies are normal.

Do not assume the first MRI was adequate. Request review by a neuroradiologist with specific attention to the symptomatic level, or proceed directly to CT myelography for superior visualization of nerve root anatomy 4.

Red Flags Requiring Urgent Evaluation:

• Myelopathic signs (gait disturbance, bowel/bladder dysfunction, bilateral symptoms)
• Progressive motor weakness
• Constitutional symptoms suggesting infection or malignancy
• History of trauma or malignancy 4

Prognosis

The natural history of cervical radiculopathy is generally favorable, with up to 75% spontaneous improvement with conservative management 2. Most patients improve over time with focused nonoperative treatment 3. However, this patient's persistent symptoms warrant aggressive diagnostic pursuit to identify the structural cause and guide definitive treatment.

Surgical outcomes for arm pain relief range from 80-90% with either anterior or posterior approaches when conservative management fails 2, but surgery should only be considered after confirming the anatomic lesion responsible for symptoms.