Case 23
History:
35 year old female with eclampsia
Findings:
Axial FLAIR sequences showing curvilinear subcortical areas of hyperintensity signal involving the posterioroccipital and parietal lobes.
Diagnosis:
Posterior Reversible encephalopathy syndrome (PRES)
Discussion:
Posterior reversible encephalopathy syndrome (PRES) typically consists of reversible vasogenic edema in the posterior circulation territories likely due to loss of vascular autoregulation. Clinically it is characterized by headache, confusion, seizure and visual loss associated with imaging findings of bilateral cortical and subcortical edema. Hypertensive encephalopathy, immunosuppressive treatment, renal failure and eclampsia are most common causes of posterior reversible encephalopathy syndrome with females predilection. T2WI and Flair are the most sensitive sequences with the lesions distributed in the subcortical regions. Enhacement is not typical but has been reported. High DWI signal and pseudonormalized ADC values are associated with cerebral infarction and may represent the earliest sign of nonreversibility as severe vasogenic edema progresses to cytotoxic edema (controversial).
References:
- S Moorthy, T S Subramaniam, N K Pprabhu, K P Sreekumar, R G Nair. Posterior Reversible Encephalopathy Syndrome in a Child with Pheochromocytoma. Ind J Radiol Imag 2002 12:3:321-324.
- Diego J. Covarrubiasa, Patrick H. Luetmera and Norbert G. Campeaua. Posterior Reversible Encephalopathy Syndrome: Prognostic Utility of Quantitative Diffusion-Weighted MRI images. American Journal of Neuroradiology 23:1038-1048, June-July 2002.
