Hospital: Complejo Hospitalario de Navarra.
Aut@r o Autores: N. Alberdi Aldasoro, P. Lopez Sala, N. Alonso Ordas, L. De Llano Ibisate, C. Saavedra Gutierrez, T. Lage Vidal.
A 68 years- old woman comes to the Emergency Room with seizure and decreased consciousness. The CT shows hypoattenuation of the parieto-occipital bilateral zone. The MRI made the next day, showed alteration of the signal into the cortex and subcortical white matter, mainly frontoparietoccipital with vasogenic edema in the posterior region.
Posterior reversible encephalopathy syndrome (PRES) is a clinical-radiological syndrome, developed by neurological symptoms and symmetric parenchymal vasogenic edema. Despite its name, it is not always reversible and not only affects to the parietoocipital regions. The pathogenesis is incompletely understood. Two opposing hypotheses are commonly cited, but the issue is controversial. The first tool used for diagnosis is CT. However, MRI is essential for diagnosis. The CT shows diffuse hypodense areas in white matter, with a predilection for posterior circulation. It is more frequent bilateral and symmetric. (1) MRI shows hypointense signal in T1 weighted sequences and hyperintense in Flair and in T2 weighted sequences, the DWI is variable (2). For a correct diagnosis it is necessary to know the clinic: they are patients with a hypertensive crisis with seizures and visual alterations. The prognosis is controversial, but it seems that the diffusion hyperintensity due to cytotoxic edema or ischemia, the hemorrhage, extensive affected volume or the involvement of brainstearm are relacionated with poor prognosis (1).
The urgent diagnosis of the syndrome has important therapeutic and prognostic implications because the reversibility of the clinical and radiologic abnormalities is contingent on the prompt control of blood pressure.
- Fischer M, Schumutzhard E. Posterior reversible encephalopathy syndrome. ? J Neurol 2017, 264: 1432-1459. - Rajesh Raman, Radhika Devaramane, Geetha Mukunda Jagadish et al. Various Imaging Manifestations of Posterior Reversible Encephalopathy Syndrom