Posterior reversible encephalopathy syndrome (PRES)

Excellent case with images here- ARRS Case Of the Day

"PRES presents with nonspecific signs and symptoms including headaches, confusion, visual disturbances, elevated blood pressure and seizures. Clinical findings are not sufficiently specific to establish the diagnosis, however, magnetic resonance imaging (MRI) pattern is often characteristic and represents an essential component of the diagnosis of PRES. PRES is an acute episode of vasogenic edema in the cerebral white matter, with a predilection for the posterior temporal, parietal and occipital regions. The vasogenic edema is likely due to autoregulatory dysfunction and endothelial dysfunction. The explanation for predilection for the posterior circulation is uncertain. Non enhanced CT shows patchy bilateral white matter nonconfluent hypodensity, and contrast enhanced CT images show variable mild patchy punctuate enhancement. The findings in the subcortical white-matter are hyperintense on T2-weighted images, hypointense or isointense on diffusion-weighted images, and hyperintense on apparent diffusion coefficient (ADC) images. PRES has been described with a number of medical conditions including hypertensive encephalopathy, eclampsia, and cytotoxic and immunosuppressive drugs (i.e. cisplatin, cyclosporin, tacrolimus, antiretroviral therapy, and erythropoietin). The reversibility of the clinical and radiologic abnormalities is dependent on prompt control of blood pressure and/or discontinuing the offending drug. If unrecognized, conversion to irreversible cytotoxic edema may occur. Rapidly developing, fluctuating or intermittent hypertension is a particular risk. "