Sarcoidosis of the central nervous system: clinical features, imaging, and CSF results

Neurological complications of systemic sarcoidosis are uncommon and the natural history and optimal treatments under-researched. With the advent of modern biological therapies, it is important to define the clinical characteristics and immunopathology of the disease.

Patients referred to and treated within the Centre for Neurosarcoidosis over a 15 year period who had biopsy-proven "highly probable" disease of the central nervous system were studied prospectively.

166 patients were studied, of whom two-thirds had involvement of the brain and spinal cord and the remainder cranial neuropathies and radiculopathy. Imaging was abnormal in all those with meningeal and parenchymal diseases, and was normal in 37% of those with cranial neuropathy. Those with leptomeningeal disease had a more severe disorder, with hydrocephalus and tissue destruction, whereas those with pachymeningeal disease had more striking imaging features but less neurological impairment. The CSF was active in 70% of cases, even when imaging was normal. Disability correlated with CSF indices in those with a leptomeningitis. Oligoclonal bands were seen in 30% of cases and correlated with disability and the presence of hydrocephalus. Unmatched bands were seen only in isolated neurological disease.

This prospective study of neurosarcoidosis increases our understanding of the pathophysiology of the disease. A reclassification of the clinical and imaging features of the disease allows an understanding of its pathophysiology and correlation with CSF indices allows an early identification of those with a more destructive disease will help to define treatment and may thereby improve outcome.