Moratalla MB. and J.F. None of these names accurately reflects the complete spectrum of this disease, as its neurologic manifestations are not exclusively “posterior”, nor are the deficits always “reversible”. , There is no direct treatment for PRES, other than removing or treating any underlying cause. The name of the condition includes the word "posterior" because it predominantly though not exclusively affects the back of the brain (the parietal and occipital lobes). , With adequate treatment, 70-90% of people with PRES make a full recovery within hours to days. 8–17% of people with PRES die, although this is not always a direct consequence of the PRES. 85(5): p. 427-432. This study determines the incidence of atypical and typical regions of involvement and unusual imaging manifestations. 70: p. 249-250.  A small proportion develops status epilepticus, where seizures are not controlled with simple measures. , With prompt recognition and treatment of PRES, many patients will recover fully, though persistent neurologic deficits can occur in 10-44%, with delay in initiation of treatment associated with unfavorable outcomes. There has been no recent trauma, toxic exposure, or infectious symptoms. Recurrent episodes of PRES can occur, and overall mortality is reported to be in the range of 3-6%. There are several notable theories regarding the pathophysiology of PRES, but the final common pathway in each is endothelial dysfunction, disruption of the blood-brain barrier, and vasogenic edema. , The incidence (number of cases per year) of PRES is not known, but increasing use of MRI scans has led to increased recognition. , The diagnosis is typically made with magnetic resonance imaging of the brain. The "immunogenic" theory suggests a role for the immune system (specifically T cells). with tacrolimus), severe infection and/or sepsis, chemotherapy, autoimmune disease, and pre-eclampsia. PRES was first described in 1996. Hinduja, A., et al., Predictors of poor outcome in patients with posterior reversible encephalopathy syndrome. , There are no formal diagnostic criteria for PRES, but it has been proposed that PRES can be diagnosed if someone has developed acute neurological symptoms (seizure, altered mental state, headache, visual disturbances) together with one or more known risk factors, typical appearance on brain imaging (or normal imaging), and no other alternative diagnosis. AJNR 29.  The name was revised in 2000 from "leukencephalopathy" to "encephalopathy" as the former suggested that it only affects the white matter of the brain, which is not the case. Chen, S., et al., Posterior Reversible Encephalopathy Syndrome After Transplantation: a Review.  A number of other associations have also been reported, including some other groups of medications, blood transfusion, elevated calcium levels, decreased magnesium levels, postpartum cerebral angiopathy, and drugs of abuse (cocaine and amphetamine). Brady, E., et al., The imaging spectrum of posterior reversible encephalopathy syndrome: A pictorial review. Cerebrospinal fluid, if obtained, may demonstrate increased protein with normal cell counts. The "cytotoxic" theory suggests that it is direct cell damage by toxins (usually medications) that precipitates the edema. The visual changes in PRES may include hemianopsia (inability to see the left or right part of the visual field), blurred vision, lack of visual awareness on one side, visual hallucinations, and cortical blindness. [8, 22] MRI is imaging modality most likely to identify abnormalities consistent with PRES, though there is no true gold standard. Powered by Gomalthemes.  In children this is more common still, at 90%. 380: p. 11-15. , The following autoimmune conditions have been found to be associated with PRES: thrombotic thrombocytopenic purpura (TTP), primary sclerosing cholangitis (PSC), rheumatoid arthritis (RA), Sjögren syndrome, polyarteritis nodosa (PAN), systemic sclerosis, systemic lupus erythematosus (SLE), granulomatosis with polyangiitis (GPA), Crohn's disease and neuromyelitis optica (NMO), as well as hemolytic-uremic syndrome (HUS).  Some patterns on electroencephalography (EEG) are also associated with a poorer outcome. Solh, Z., et al., Neurological PRESentations in Sickle Cell Patients Are Not Always Stroke: A Review of Posterior Reversible Encephalopathy Syndrome in Sickle Cell Disease. Zama, D., et al., A survey on hematology-oncology pediatric AIEOP centres: The challenge of posterior reversible encephalopathy syndrome.Eur J Haematol, 2018. Mol Neurobiol, 2016.  In many cases there is evidence of constriction of the blood vessels (if angiography is performed), suggesting a possible overlap with reversible cerebral vasoconstriction syndrome (RCVS). 14(9): p. 914-925. , After an episode of PRES, even when it was associated with seizure activity, only a small proportion of people remains at risk of ongoing seizures and the majority can eventually discontinue anticonvulsant treatment. [5-7] , PRES is associated with a number of conditions, including hypertension, renal disease, preeclampsia, autoimmune disease, and use of immunomodulatory medications. 8–17% of people with PRES die, although this is not always a direct consequence of the PRES. On magnetic resonance imaging (MRI) of the brain, areas of edema (swelling) are seen. If PRES is recognized and treated appropriately, a majority of patients recover without neurologic sequelae. Posterior Reversible Encephalopathy Syndrome, Part 2: Controversies Surrounding Pathophysiology of Vasogenic Edema. The latter hypothesis is supported by the frequent finding of diffuse blood vessel spasms (vasoconstriction) in many people with PRES, and the evidence for decreased perfusion, although the spasm may also be a consequence of the blood vessel damage rather than the cause.