Presentations and outcomes of neurosarcoidosis: a study of 54 cases

Background: Sarcoidosis is an inflammatory granulomatous disease affecting multiple organ systems. Neurosarcoidosis (CNS involvement) is seen in approximately 25% of patients with systemic sarcoidosis, although it is subclinical in most of these cases. Because of its rarity, exposure of neurologists to the clinical spectrum of NS is limited to case reports or short case series. Patients and Methods: A database of 3900 patients treated at the Vanderbilt Multiple Sclerosis Clinic between 1995 and 2008 was searched for 'neurosarcoidosis', 'neurosarcoid', 'sarcoidosis' and 'sarcoid'. Of the 162 patient records that were retrieved, 54 patients were found to meet the criteria for definite, probable or possible neurosarcoidosis and were reviewed, including their clinical presentation, Cerebrospinal fluid (CSF) findings, Magnetic resonance imaging (MRIs), biopsy results, treatment, and where available, outcomes 4 months to 20 years after onset of the presenting illness. Results: Clinical presentations and imaging findings in NS were varied. Cranial nerve abnormalities were the most common clinical presentation and involvement of the optic nerve in particular was associated with a poor prognosis for visual recovery. Isolated involvement of lower cranial nerves had a more favorable outcome. T-2 hyperintense parenchymal lesions were the most common imaging finding followed by meningeal enhancement. Long-term treatment consisted of prednisone and/or other immunomodulators (azathioprine, methotrexate or mycophenolate mofetil). Conclusions: Unlike systemic sarcoidosis, there is difficulty in making tissue diagnosis when involvement of CNS is suspected. MRI and CSF studies are sensitive in the detection of CNS inflammation but lack specificity, making the ascertainment of neurosarcoidosis a clinical challenge. In addition the low prevalence of the disease makes clinical trials difficult and therapeutic decisions are likely to be made from careful reporting from case studies.