Background: Posterior reversible encephalopathy syndrome (PRES), is characterized by headache, lethargy, visual complaints and epileptic seizures. Brain imaging findings include abnormalities of the white matter and the grey matter.The diagnosis currently relies on clinical manifestations and typical neuroimaging findings. Different pathophysiological factors can play role in the disease process. The purpose of this study is to review causes, clinical aspects, imaging-laboratory findings and prognosis in patients diagnosed with PRES. Method: Patients who showed clinical and magnetic resonance imaging (MRI) findings consistent with PRES between January 2011 and December 2014 were included in the study. Patient data were collected retrospectively from hospital records. Results:Total number of patients was 22 (18 female, 4 male). Median age was 28 years (range 18-84). Comorbid conditions included eclampsia (n=10, 45%), pre-eclampsia (n=1, 4.5%), HELLP (hemolysis, elevated liver enzymes, low platelet count) syndrome (n=1), primary kidney disease (n=3, 13%). Acute elevation of blood pressure was found in 9 patients (40%). Five patients (22%) were using steroids or immunosupressive drugs. Typical PRES imaging pattern with bilateral parieto-occipital involvement was present in 15/22 patients (68%) and occipital involvement was present in 3/22 patients (14%). Atypical neuroimaging features included frontal involvement in 10 patients (45%), basal ganglia gray matter lesion in 1 patient (4%) and the cerebellum was involved in 3 patients (14%). Serum LDH level was high in 13 patients (59%). Hypoalbuminemia was detected in 12 patients (54%). Conclusion: Although hypertension is thoughtto be the main pathologic factor in the disease process, endothelial dysfunction seems to be equally important.
Posterior Leukoencephalopathy Syndrome

This is the report of a 32-year-old man with Behçet’s disease described dizziness, double vision and headache. The cranial MRI demonstrated a ring enhancing nodular lesion in left medial occipital lobe, and T2 hyperintense lesion in diencephalon mimicking abscesses. A stereotactic biopsy was performed. The histology showed features of neuro-Behçet’s disease and an abscess was ruled out. During the procedure till the histopathologic results were gathered he was given ceftriaxone and metronidazole when cerebellar signs appeared. Cranial MRI showed additional symmetrical hyperintensities in bilateral cerebellar dentate nuclei which was attributed to metronidazole toxicity. Repeat MRI performed forty days later showed complete resolution of both dentate hyperintensities and diencephalic and occipital ring enhancing lesions. This is the first case of neuro-Behcet’s disease complicated by metronidazoleinduced encephalopathy. This case also showed that nodular ring enhancing lesions can be seen in neuro-Behçet’s disease and can lead to difficulties in diagnosis and management.
Dizziness