Behcet’s disease (BD) was firstly reported by the Turkish doctor Behcet in 1937. It is an agnogenic and multi-systemic disease based on small vessel vasculitis. The typical clinical performance is eye-mouth-genital triad, which means recurrent oral ulcer, ocular uveitis and genital ulcer.The condition of this disease recurred but most patients have a good prognosis.
The etiology and pathogenesis are still unclear. Generally it is believed that it may due to genetic, immune factors or pathogen infections. Immune factors play an important role in the pathogenesis of BD Cytokines, such as IL-1, IL-8, TNF-α, heat shock proteins, macrophages activation and autoimmune factors, etc. are all participated in the onset[2-4].
BD is mainly distributed along the historical Silk Road. Recent years, coutries where there were none BD reported or rarely cases. In the existing literature, Turkey has the highest incidence (20-240 patients in 100,000 people)[6, 7]. The incidence in China is 14 patients in 100,000 people. Europe has low incidence[9, 10].
The diagnosis of BD currently relies only on clinical symptoms, we used to use the ISG diagnostic criteria developed in 1990. In 2012, international teams from 27 countries submitted data based on 2556 BD cases and 1163 BD-like cases or cases with at least one of the major BD symptoms to adjust the international criteria for BD（ICBD）. This criteria improved the sensitivity and specificity of BD diagnosis greatly, allowing patients to get early diagnosis and timely treatment, and obtain a good prognosis.
BD is classified into vascular type, neurological type, gastrointestinal type, etc. according to the damage of its visceral systems. The first BD case with nervous system involvement was reported by Knapp in 1941. Then Cavara and D’Ermo proposed a widely accepted term “neuro-Behcet’s disease” for this type. Patients with nervous system involvement of BD have been reported to account for 3.2%-49%, mostly about 5%[15, 16]. Nervous system symptoms mostly occur 4-6 years after the onset of BD. But some of the patients have neurological symptoms at the same time with or before the classical symptoms, which may lead to diagnostic confusion, and these patients might be more than reported.
The pathological feature is various types of arteriovenous vasculitis which mainly affect small vessels in multiple systems, in the central nervous system, it appears as focal or multiple brain parenchymal damage[18, 19]. When affect large vessels, BD mainly act as cerebral venous sinus thrombosis. Artery involvement is rare compared with venous involvement, manifesting as arterial stenosis and/or aneurysm formation which often leads to intracranial and/or subarachnoid hemorrhage or arterial infarction. [21-23].