_{The cerebral venous system and anatomical predisposition to high altitude headache}

Wilson MH et al. – The authors postulated that HAH results when hypoxia–associated increases in cerebral blood flow occur in the context of restricted venous drainage, and is worsened when cerebral compliance is reduced. They explored this hypothesis in three studies. Arterial hypoxaemia is associated with cerebral and retinal venous distension, whose magnitude correlates with HAH burden. Restriction in cerebral venous outflow is associated with retinal distension and HAH. Limitations in cerebral venous efferent flow may predispose to headache when hypoxia–related increases in cerebral arterial flow occur.