Clinical and Radiological Spectrum of Posterior Reversible Encephalopathy Syndrome

Abstract

ObjectiveSymptoms of posterior reversible encephalopathy syndrome (PRES) include headache, altered mental status, visual disturbances, and seizures. Typical radiological features include edema of the parieto-occipital lobes. The purpose of this study is to review the clinical and radiological findings in patients diagnosed with PRES.MethodsAll patients diagnosed with PRES between January 2006 and December 2012 were retrospectively included in this study. We reviewed demographic and clinical characteristics, and radiological findings.ResultsWe identified 16 patients with PRES. The most common clinical presentation was seizure (n = 12, 75%). Clinical recovery occurred in all patients within days (mean, 5.7 ± 4.6 days). Comorbid conditions included hypertension (n = 4, 25%), cytotoxic medications (n = 3, 18.8%), sepsis (n = 4, 25%), malignancy (n = 4, 25%), subarachnoid hemorrhage (n = 1, 6.3%), autoimmune disorders (n = 1, 6.3%) and eclampsia (n = 1, 6.3%). The most commonly involved location was the parieto-occipital lobe (n = 13, 81.3%). Atypical radiological findings included significant basal ganglia involvement in 4 episodes; brainstem in 3, cerebellum in 2, and thalamus in 3. Eleven patients (68.8%) underwent diffusion-weighted imaging and apparent diffusion coefficient mapping. Of those, 9 patients (81.8%) had hypo- or isointensity on diffusion-weighted imaging. On the apparent diffusion coefficient map, 10 patients (90.9%) had hyperintensity, and the other had normal values.ConclusionWe suggest that PRES may occur in patients with complex systemic conditions. The prognosis of PRES is usually benign. Physicians should be aware of certain atypical radiological findings to avoid a delayed diagnosis of PRES, as delayed diagnosis and treatment can result in permanent neurological sequlae.

Posterior reversible encephalopathy syndrome after intrathecal methotrexate infusion: a case report and literature update

“…Additionally, patients with severe hypertension are reported to have a milder vasogenic oedema than normotensive patients (20). This result would have been unexpected, if the mechanism of PRES was exclusively severe hypertension with dysfunctional autoregulation mechanisms (21). Since several patients with PRES have normal blood pressure, endothelial damage and default of the blood-brain barrier could explain the pathogenesis of the syndrome (22).…”

“…FLAIR and DWI images can be helpful to distinguish vasogenic from cytotoxic oedema, the second being rather unusual in PRES lesions (12). Vasogenic oedema typically shows isointensity or hypointensity in DWI and hyperintensity on the ADC map, while cytotoxic edema shows hyperintensity in DWI and hypointensity on the ADC map (21). The presence of vasogenic oedema within the posterior arterial watershed region suggests a reversible process with a favourable prognosis.…”

“…Risk factors for PRES in paediatric cancer patients are hypertension (not necessarily acute) and remission induction chemotherapy. Common complications of treatment in malignancies, such as hypertension, systemic inflammatory response, sepsis, hyperviscosity syndrome, coagulopathy and electrolyte imbalance, could affect negatively the prognosis and alter the course of the disease (21). Most of the patients develop PRES during the induction phase of treatment (26).…”

Posterior Reversible Encephalopathy Syndrome (PRES); in a 5 years old, dialysis dependent child with chronic kidney disease.

“…These abnormalities demonstrate the areas of vasogenic oedema. The spared medial occipital structures help to distinguish PRES from posterior cerebral artery infarcts [11]. Abnormalities are also seen in the temporal lobes, cerebellum, basal ganglia and brain stem showing high signal on T2-weighted attenuated FLAIR sequences.…”

Posterior Reversible Encephalopathy Syndrome in a Patient with Severe Uremia without Hypertension

“…DWI shows increased diffusion in the affected regions, suggesting vasogenic edema in these areas. The preferential involvement of the parietal and occipital lobes is explained by sympathetic nervous system innervation of the posterior cerebral circulation (24,25). Fugate et al reported that the most commonly involved location in PRES was the parieto-occipital brain region (94%), followed by the frontal lobe (77%), the temporal lobe (64%), the cerebellum (53%), the basal ganglia (34%), and the brainstem (27%) (26).…”