Recent progress in hemorrhagic moyamoya disease

Moyamoya disease (MMD) is a chronic progressive cerebrovascular disease, which can be divided into three types: ischemic, hemorrhagic, and asymptomatic. Hemorrhagic MMD has attracted considerable attention due to its distinctive imaging features and the controversy over the treatment. This report presents a comprehensive review of the literature on hemorrhagic MMD, focusing on the epidemiological characteristics, etiology and pathogenesis, imaging features, predictors of hemorrhage, and treatment options and their efficacy of hemorrhagic MMD. Hemorrhagic MMD mainly occurs in adult patients in Asian countries, and many factors may contribute to the etiology and development of this disease. Hemorrhagic MMD has two major imaging features: the dilatation and abnormal branching of anterior choroidal artery or posterior communicating artery, and multiple microbleeds, which may predict subsequent hemorrhage. The treatment for hemorrhagic MMD is not standardized, and large sample prospective randomized clinical trials may help to determine which method is better. In hemorrhagic MMD patients, more attention should be paid to cognitive function and quality of life, and these assessments should be included in the evaluation of effectiveness of treatment modalities.