Posterior reversible encephalopathy syndrome with atypical regions in eclamptic patients: A challenge for radiologists

PurposesTo determine the distribution and incidence of atypical regions of involvement of PRES in eclapmtic patients by using MR imaging.Material and methodsA prospective study was approved by the ethical committee of our institution during the period between October 2011 and March 2012. Twenty two registered eclamptic patients (age ranged from 20–38 years; average 29 years) who had clinical signs and symptoms of PRES were recruited in the study, all patients were referred from Gynecology and Obstetric department, for brain MRI to evaluate PRES after clinical suspicion. All images were reviewed for the presence of high signal intensity on FLAIR and T2WI, for the severity of the vasogenic brain edema, on the basis of the extent of hyperintensity on FLAIR imaging. DWI was also interpreted for the presence or absence of areas of restricted diffusion corresponding to the hyperintensity areas on T2WI and FLAIR images.ResultsThe most common clinical presentations were seizures, and altered mental status seen in 11 patients (50%). Other clinical presentations included headache (4 [18.1%]), visual disturbance in one patient and loss of consciousness in one patient. Most commonly involved location was the parieto-occipital brain region, which was seen in 19 (86.3%) of the (22) patients. This was followed by the frontal lobe in 13 patients (59%), the temporal lobe in 3 (13.6%), Basal Ganglia in 3 patients and cerebellum in 3 patients, 11 (50%) had subcortical involvement of white matter edema and 9 (40.9%) had cortical involvement. Lesions were asymmetric in nearly half of the cases (n = 10[45.5%]), unilateral in 3 patients. Restricted diffusion was present in 9 patients (40.9%), and no hemorrhage was present in all patients. As regarding severity of edema in FLAIR, half of patients had moderate edema (n = 11) while only 2 patients had severe edema and 9 had mild edema.ConclusionPRES can affect anterior circulation structures and atypical regions fairly frequent than commonly known. However, a posterior predominance is certainly seen in each lobe. Atypical regions of involvement represents a challenge for radiologist and necessitate strict clinical correlation and follow up.