Posterior Reversible Encephalopathy Syndrome and Reversible Cerebral Vasoconstriction Syndrome as Syndromes of Cerebrovascular Dysregulation

Abstract

PURPOSE OF REVIEW This article describes the causes, clinical and imaging features, management, and prognosis of posterior reversible encephalopathy syndrome (PRES) and reversible cerebral vasoconstriction syndrome (RCVS), in which the underlying pathophysiology is related to reversible dysregulation of the cerebral vasculature. RECENT FINDINGS PRES and RCVS are descriptive terms, each bringing together conditions with similar clinical-imaging manifestations. Headache, visual symptoms, seizures, and confusion occur in both syndromes. RCVS is usually heralded by recurrent thunderclap headaches, whereas encephalopathy and seizures are typical in PRES. In PRES, brain imaging shows reversible vasogenic edema that is typically symmetric and located in subcortical regions (mostly posterior predominant). In RCVS, brain imaging is often normal; cerebral angiography shows segmental vasoconstriction-vasodilatation affecting the circle of Willis arteries and their branches. Aside from shared clinical features, significant imaging overlap exists. Both PRES and RCVS can be complicated by ischemic and hemorrhagic brain lesions; angiographic abnormalities frequently occur in PRES and vasogenic edematous lesions in RCVS. Common triggers (eg, eclampsia, vasoconstrictive and chemotherapeutic agents) have been identified. Abnormal cerebrovascular tone and endothelial dysfunction may explain both syndromes. Management of these syndromes includes the removal of identified triggers, symptomatic treatment of headache or seizures, and moderate blood pressure control. Both syndromes are self-limited, with clinical recovery occurring within days to weeks. Long-term deficits and mortality are uncommon. SUMMARY PRES and RCVS have been well characterized and acknowledged to have significant overlap. Advances in our understanding of pathophysiology and risk factors for poor outcome are expected to optimize the management of these not uncommon syndromes.

Pathophysiology of reversible cerebral vasoconstriction syndrome

“…An expanding list of possible etiologies of RCVS has been identified [ 2 , 3 , 15 , 17 , 22 ]. Comprehensive reviews can be found elsewhere [ 1 , 23 , 24 ]. Overall, vasoactive substances and post-partum state are the most common secondary causes of RCVS.…”

“…Based on the radiological features, dysregulation of cerebral vascular tone has been considered the central element in the pathogenesis of RCVS [ 1 , 23 , 24 ]. An abrupt, unpredictable alteration of central vascular tone associated with excessive sympathetic discharge may explain the cerebral vasoconstriction and, the less mentioned, vasodilatation.…”

“…Studies from overlapping syndromes or spectral disorders of RCVS also support the existence of endothelial dysfunction at least in selected cases. PRES, a well-recognized cerebral endotheliopathy [ 72 ], can be found in a substantial proportion of patients with RCVS [ 6 , 13 , 14 , 16 , 17 ], and with similar characteristics of RCVS including dysregulated vascular tone, acute severe headaches, blood pressure surge, and secondary etiologies such as immunosuppressive or cytotoxic agents [ 24 , 47 , 48 ]. Post-partum angiopathy, one of the secondary RCVS, exhibits overlapping clinical, laboratory and radiographical features with the obstetric emergencies eclampsia and preeclampsia [ 22 , 73 , 74 ].…”

Clinical Problem Solving: Decreased Level of Consciousness and Unexplained Hydrocephalus

“…Hypertension should also be treated, though specific guidelines regarding target blood pressure and optimal anti-hypertensive have not been established. 15 Experts recommend that fluctuations in blood pressure and hypotension be avoided due to the risk of precipitating cerebral hypoperfusion and secondary ischemia. 15 Treatment of “malignant” forms of PRES may consist of ICU-level care, ventilatory support, treatment of increased ICP, and management of secondary complications including as insertion of EVDs, craniectomy or posterior fossa decompression, and hematoma evacuation.…”

“…15 Experts recommend that fluctuations in blood pressure and hypotension be avoided due to the risk of precipitating cerebral hypoperfusion and secondary ischemia. 15 Treatment of “malignant” forms of PRES may consist of ICU-level care, ventilatory support, treatment of increased ICP, and management of secondary complications including as insertion of EVDs, craniectomy or posterior fossa decompression, and hematoma evacuation. 16 No specific guidelines regarding treatment of increased ICP in PRES have been established, and general recommendations regarding the treatment of cerebral edema in neurocritical care patients should be followed, while remaining cognizant of patient’s comorbidities and concomitant diseases.…”