Diagnostic Workup for Neuritis
The diagnostic workup for neuritis should include neurological consultation, appropriate imaging (MRI with and without contrast), laboratory testing for reversible causes, and electrophysiologic studies to determine the type and severity of nerve involvement. 1, 2
Initial Assessment
- Neurological consultation is essential for proper evaluation and management 1
- Clinical history focusing on:
- Onset and progression of symptoms
- Distribution pattern (focal vs. multifocal vs. diffuse)
- Associated symptoms (pain, weakness, sensory changes)
- Exposure to toxins or medications
- Recent infections
- Autoimmune conditions
Imaging Studies
- MRI with and without contrast of the affected area 1, 2
- For peripheral neuritis: MRI of affected limb/region
- For optic neuritis: MRI brain and orbits
- For myelopathy: MRI of spine
- Helps rule out compressive lesions
- Evaluates nerve root enhancement/thickening
- Identifies inflammatory changes
Laboratory Testing
- Complete blood count
- Comprehensive metabolic panel
- Inflammatory markers (ESR, CRP)
- Blood glucose, HbA1c
Screening for reversible causes 1:
- Vitamin B12 and folate levels
- Thyroid function tests (TSH)
- HIV testing
- Serum protein electrophoresis
Autoimmune/inflammatory workup:
Electrophysiologic Studies
- Electrodiagnostic testing 1, 2, 4:
- Nerve conduction studies (NCS)
- Electromyography (EMG)
- Helps differentiate between:
- Axonal vs. demyelinating neuropathy
- Motor vs. sensory involvement
- Focal vs. multifocal vs. diffuse patterns
- Visual evoked potentials (for optic neuritis) 1
Cerebrospinal Fluid Analysis
- Lumbar puncture for CSF analysis 1, 2:
- Cell count (WBCs)
- Protein and glucose levels
- Gram stain and culture
- Cytology (to rule out malignancy)
- Viral PCR testing when appropriate
- Oligoclonal bands (for demyelinating conditions)
Specific Considerations by Type of Neuritis
For Peripheral Neuritis
- Complete workup as above
- Consider nerve biopsy in selected cases with unclear diagnosis 4
For Optic Neuritis
- Complete ophthalmological evaluation including funduscopy and fluoroangiography 1
- Visual field testing
- Visual evoked potentials
- Anti-MOG and anti-AQP4 antibodies 3
For Immune Checkpoint Inhibitor-Related Neuritis
- More aggressive workup and management due to potential rapid progression 1, 2
- Monitor closely for respiratory involvement
Management Considerations
The diagnostic workup directly informs treatment decisions:
- For mild cases: Observation and symptomatic treatment may be sufficient
- For moderate to severe cases: Immunosuppressive therapy may be required
- For immune-mediated neuritis: Corticosteroids, IVIG, or plasmapheresis 1, 2
- For optic neuritis: High-dose IV methylprednisolone 1
Pitfalls to Avoid
- Delayed diagnosis: Neuritis can progress rapidly, particularly immune-mediated forms
- Incomplete workup: Missing treatable causes leads to poor outcomes
- Failure to monitor respiratory function: Critical in cases of ascending neuritis
- Overlooking associated conditions: Neuritis may be part of a systemic disorder requiring comprehensive management
Following this structured approach ensures thorough evaluation of neuritis, leading to accurate diagnosis and appropriate treatment to minimize morbidity and mortality.