From the Guidelines
The workup for neurosarcoidosis should begin with a thorough clinical evaluation, including a detailed neurological examination and medical history, as this condition can affect any portion of the nervous system and have a significant impact on the patient's quality of life 1. The initial testing should include basic laboratory studies such as complete blood count, comprehensive metabolic panel, erythrocyte sedimentation rate, C-reactive protein, and serum angiotensin-converting enzyme (ACE) levels.
- Chest imaging with a high-resolution CT scan is essential as pulmonary involvement is common in sarcoidosis 1.
- Brain and spine MRI with gadolinium contrast is crucial to identify characteristic lesions, particularly leptomeningeal enhancement.
- Cerebrospinal fluid analysis should be performed to evaluate for elevated protein, pleocytosis, oligoclonal bands, and increased ACE levels.
- Ophthalmologic examination is important to detect ocular involvement. Definitive diagnosis typically requires tissue biopsy showing non-caseating granulomas, preferably from an affected site, though this may be challenging for neural tissue 1. If accessible lesions are present elsewhere (such as skin, lung, or lymph nodes), these may be biopsied instead.
- PET scanning can help identify potential biopsy sites and assess disease activity.
- Electrodiagnostic studies may be useful when peripheral neuropathy is suspected. This comprehensive approach is necessary because neurosarcoidosis can mimic many other neurological conditions, and establishing a definitive diagnosis is essential for appropriate treatment planning, given the high risk for significant irreversible neurologic loss 1.
From the Research
Diagnostic Approach
- The diagnosis of neurosarcoidosis is established by the clinical syndrome, imaging and histopathological findings, and exclusion of other causes 2
- Magnetic resonance imaging (MRI) is often used in the diagnostic evaluation and follow-up of patients with neurosarcoidosis, and familiarity with the variety of MRI appearances is important 3
- Ancillary tests such as MRI and cerebrospinal fluid analysis are compatible, and alternative diagnoses are reasonably excluded in patients with established extraneural sarcoidosis 4
Clinical Presentation
- Neurosarcoidosis typically presents as recognizable syndromes that can be approached in a rational, systematic fashion 2
- Clinically overt granulomatous involvement of the nervous system can be seen in up to 10% of patients with sarcoidosis 4
- Symptoms of cauda equina involvement by neurosarcoidosis include leg numbness, leg weakness, perineal numbness, pain, and incontinence 5
Treatment
- Corticosteroids remain as first-line therapy for neurosarcoidosis 6
- Anti-tumor necrosis factor (anti-TNF) therapy has been demonstrated to be effective in the treatment of neurosarcoidosis, leading to improved outcomes 6
- Second-line agents such as methotrexate, infliximab, and azathioprine may be associated with improvement in patients with neurosarcoidosis 5
- Treatment regimen of neurosarcoidosis should be formulated with an emphasis on long-term strategy, taking into consideration the extent of the disease, severity, functional impairment, comorbidities, and patient's preference 4
Disease Characteristics
- Neurosarcoidosis is a granulomatous disease with protean manifestations that may affect any part of the central and peripheral nervous system 6
- Involvement of the cauda equina is an understudied phenotype of neurosarcoidosis, and questions remain regarding its natural history and optimal approach to management 5
- Characteristic features of cauda equina involvement by neurosarcoidosis include chronically delayed presentations, nodular enhancement on MRI, poor response to corticosteroids, and substantial resultant neurologic disability 5