Abstract
Cerebral autoregulation controls cerebral blood flow(CPF)in response to changes and fluctuation in blood pressure through strict dynamic adjustment of arterial calibre, but the impact of autoregulatory mechanism on local vascular responses and microvascular perfusion remains not fully understood and remain a subject of research, regulation of cerebral blood flow is a key and essential protective and compensatory mechanism for a healthy brain function and rely on interplay of complex vascular control mechanism, Cerebral autoregulation can be evaluated either a static or dynamic phenomenon, there is a lot of body of evidence to show the role of dynamic autoregulation, the clinical data on static autoregulation is limited, in this minireview we will concentrate on the not uncommon and commonly undiagnosed clinical syndromes due to failure of cerebral autoregulation cerebral such as reversable cerebral vasoconstrictor syndrome(RCVS) and posterior reversable encephalopathy Syndrome(PRES)