What is the appropriate next diagnostic and therapeutic approach for a patient with a 5‑month history of left‑sided increased tone, distal tingling, fatigue, brain fog, normal electromyography, non‑contrast brain MRI, indeterminate cervical spinal cord lesions possibly artifact, and new hand numbness, forearm tingling, and achy wrists?

Next Steps for Progressive Myelopathic Symptoms with Indeterminate Cervical Lesions

Obtain an urgent contrast-enhanced brain MRI and a repeat cervical spine MRI with gadolinium using optimized demyelinating protocols (including at least two T2-weighted sequences such as T2 and STIR, plus axial imaging) to definitively characterize the indeterminate cervical lesions and evaluate for dissemination in space and time consistent with multiple sclerosis or other inflammatory myelopathies. 1

Immediate Diagnostic Priorities

Advanced Spinal Cord Imaging

• Repeat cervical MRI with contrast is mandatory because the initial non-contrast study showed indeterminate lesions that could represent artifacts, and the patient now has progressive symptoms including new upper extremity involvement (hand numbness, forearm tingling, achy wrists). 1

• The imaging protocol must include:

  • At least two sagittal sequences with different contrasts (T2-weighted and proton-density and/or STIR) to increase confidence in lesion detection and distinguish true lesions from flow-related artifacts. 1
  • Axial T2-weighted imaging to verify changes seen in the sagittal plane, as STIR sequences alone are susceptible to flow-related artifacts that cause false-positive interpretations. 1
  • Gadolinium contrast administration using a "one-stop shop" strategy (performed directly after brain MRI) to identify active inflammation, though only a small percentage of spinal cord lesions enhance. 1
  • Minimum field strength of 1.5 Tesla with 3mm slice thickness to meet diagnostic standards. 1

• Extend imaging to the entire spinal cord (cervical through thoracolumbar), as approximately 40% of spinal cord lesions occur in the thoracolumbar region, and whole-cord imaging identifies patients at higher risk of MS confirmation. 1

Brain MRI with Contrast

• Obtain contrast-enhanced brain MRI even though the initial non-contrast study was performed, because:
  • The simultaneous presence of gadolinium-enhancing and non-enhancing lesions establishes dissemination in time for MS diagnosis. 1
  • Brain lesions facilitate MS diagnosis and predict conversion to clinically definite MS. 1
  • Spinal cord MRI is specifically recommended when brain MRI results are equivocal or inconclusive. 1

Critical Differential Diagnosis Considerations

Multiple Sclerosis (Primary Concern)

The clinical presentation—left-sided increased tone, progressive sensory symptoms, fatigue, brain fog, normal EMG, and indeterminate cervical lesions—raises significant concern for MS or other demyelinating disease. 1

• Spinal cord lesions are predictive for conversion to clinically definite MS, and asymptomatic cord lesions herald increased risk of short-term progression. 1
• The 5-month duration with progressive symptoms and new upper extremity involvement suggests ongoing disease activity requiring urgent clarification. 1
• Normal EMG does not exclude MS or myelopathy, as EMG primarily assesses peripheral nerve and muscle function, not central demyelinating lesions. 2

Alternative Myelopathies to Exclude

• Neuromyelitis optica (NMO) spectrum disorders must be excluded before applying MS diagnostic criteria, particularly in patients with prominent spinal cord involvement. 1
• Compressive myelopathy from degenerative disease, though the normal EMG and progressive upper motor neuron signs (increased tone) make this less likely. 1
• Inflammatory/autoimmune myelopathies including sarcoidosis and vasculitis. 2

Additional Diagnostic Testing

Laboratory Evaluation

While awaiting imaging, obtain:

• Serum NMO-IgG (aquaporin-4 antibody) to exclude neuromyelitis optica spectrum disorder before pursuing MS diagnosis. 1
• Vitamin B12 with metabolites (methylmalonic acid) as B12 deficiency can cause myelopathy with increased tone and sensory symptoms. 2
• Thyroid function (TSH) to exclude hypothyroid-related neurological dysfunction. 2
• Serum protein immunofixation electrophoresis to detect monoclonal gammopathies that can cause progressive myelopathy. 2

Lumbar Puncture Consideration

• CSF examination should be strongly considered if imaging confirms spinal cord lesions, as positive CSF findings (oligoclonal bands, elevated IgG index) support MS diagnosis and contribute to dissemination in space criteria for primary progressive MS. 1

Common Pitfalls to Avoid

• Do not dismiss indeterminate cervical lesions as artifacts when the clinical picture is progressive and includes upper motor neuron signs (increased tone) plus new symptoms. The combination demands definitive characterization. 1

• Do not rely on non-contrast MRI alone for evaluating suspected demyelinating disease, as contrast enhancement identifies active lesions and establishes dissemination in time. 1

• Do not assume normal EMG excludes significant neurological disease—EMG assesses peripheral nerves and muscles, not central white matter tracts or spinal cord pathology. 2

• Do not order repeat spinal MRI with the same non-contrast protocol that produced indeterminate results; the repeat study must include contrast and optimized sequences specifically designed to detect demyelinating lesions and distinguish them from artifacts. 1

Urgent Neurology Referral

Refer immediately to neurology given:

• Progressive myelopathic symptoms over 5 months 2
• Upper motor neuron signs (increased tone) 2
• Indeterminate spinal cord lesions requiring expert interpretation 1
• Potential need for disease-modifying therapy if demyelinating disease is confirmed 1

The neurologist can coordinate advanced imaging interpretation, determine the need for lumbar puncture, and initiate appropriate disease-modifying treatment if MS or another treatable inflammatory myelopathy is diagnosed. 1, 2