可逆性后部脑白质病-图文课件.ppt

1、Posterior reversible encephalopathy syndrome (PRES) was first reported by Hinchey in 1996.1. It may occur due to a number of causes predominantly malignant hypertension, eclampsia, drugs such as tacrolimus, cyclosporine, autoimmune disease and patients undergoing organ transplant. After the timely a

2、nd effective treatment of the clinical manifestation and neuroimaging changes can fully recover, neurological sequelae generally does not exist The most common clinical symptoms and signs are headache, altered alertness and behavior changes ranging from drowsiness to stupor, seizures, vomiting, ment

3、al abnormalities including confusion and abnormalities of visual perception. Seizures may begin focally but usually become generalized.Classically PRES ：characterized by hyperintensity on T2-weighted and FLAIR images bilaterally and symmetrically in the parieto occipital regions which is caused by s

4、ubcortical white matter vasogenic edema. Atypical PRES：other regions of the brain are involved except the parieto-occipital lobes .Includes brain stem, cerebellum, basal ganglia, and frontal lobes. Atypical imaging appearances include contrast enhancement , hemorrhage, unilaterality and restricteddi

5、ffusion on MRI and involvement of gray matter.1、The more popular theory suggests that hypertension leads to failure of autoregulation , subsequent hyperperfusion, and vasogenic edema.2、The other theory suggests that vasoconstriction and hypoperfusion leads to brain ischemia and subsequent vasogenic

6、edema. The relative paucity of sympathetic innervations in the posterior brain results in increased susceptibility to hyperperfusion and vasogenic edema during acute blood pressure elevations. Most authorities believe that hypertensive encephalopathy and eclampsia share similar pathophysiologic mech

7、anismsA 25-year old lady, primigravida；On the 3rd day of postpartum with sudden onset of giddiness, headache, vomiting, bilateral blurring of vision followed by generalized tonic-clonic seizure. Her BP was within normal limits. Blood and urine routine assays were normal, and no proteinuria was detec

8、ted during both the pregnancy and puerperium. She underwent Persistent Occipito-posterior position and delivered a healthy male baby and her BP both during her surgery and postpartum period was normal.A 21-year old lady,primigravida with 30 weeks gestation；On the 6th day of postpartum with h/o sudde

9、n onset of headache, vomiting, bilateral blurring of vision followed by recurrent generalized tonic- clonic seizure. She had regular ANC checkup and her BP was withinnormal limits. Blood and urine routine tests were normal, and no proteinuria was detected during both the pregnancy and puerperium. Sh

10、e underwent emergency LSCS for PROM delivered a still-birth and her BP both during her surgery and postpartum period wasChanges in diffusion-weighted magnetic resonance imaging (DWI) and apparent diffusion coefficient (ADC) in posterior reversible encephalopathy is well documented, and can successfu

11、lly differentiate PRES from early cerebral ischemia. DWI is the study of choice in PRES to discriminate between vasogenic and cytotoxic edema ,thereby, being helpful as a screening imaging methodology in the setting of ischemic complications of PRES in identifying irreversible tissue damage . ADC ma

12、pping can be useful to rule out other conditions that can mimic PRES, such as central pontine myelinolysis.It is of particular importance not to exclude PRES as a possible diagnosis when we have the appropriate clinical presentation which is not accompanied by the typical radiological findings since this clinical-radiological syndrome can often be manifested with atypical MRI findings. The success of the therapy lies primarily in recognizing these findings.