The spectrum of nervous system involvement in Behçet's syndrome and its differential diagnosis.

Behçet's Syndrome (BS) is a multi-system, vascular-inflammatory disease of unknown origin, involving the nervous system in a subgroup of patients. The growing clinical and imaging evidence suggests that primary neurological involvement in BS may be subclassified into two major forms: the first one, which is seen in the majority of patients, may be characterized as a vascular-inflammatory central nervous system (CNS) disease, with focal or multifocal parenchymal involvement mostly presenting with a subacute brainstem syndrome and hemiparesis; the other, which has few symptoms and a better neurological prognosis, may be caused by isolated cerebral venous sinus thrombosis and intracranial hypertension. These two types rarely occur in the same individual, and their pathogenesis is likely to be different. Isolated behavioral syndromes and peripheral nervous system involvement are rare, whereas a nonstructural vascular type headache is relatively common and independent from neurological involvement. Neurologic complications secondary to systemic involvement of BS such as cerebral emboli from cardiac complications of BS and increased intracranial pressure due to superior vena cava syndrome, as well as neurologic complications related to BS treatments such as CNS neurotoxicity with cyclosporine and peripheral neuropathy with the use of thalidomide or colchisin are considered as secondary neurological complications of this syndrome. As the neurological involvement in this syndrome is so heterogeneous, it is difficult to predict its course and prognosis, and response to treatment. Currently, treatment options are limited to attack and symptomatic therapies with no evidence for the efficacy of any long term preventive treatment.