Intensivist Charleston Area Medical Center, United States
Introduction: Posterior reversible encephalopathy syndrome (PRES) is a disorder characterized by typical neuroimaging findings, associated with broad and variable neurological symptoms. Classic brain magnetic resonance imaging (MRI) findings involve vasogenic edema in the parietal-occipital areas of the posterior circulation in the supratentorial region. However, this is not always the case and failure to recognize PRES could result in catastrophic outcome.
Description: We report a rare case of PRES primarily involving the posterior fossa, presenting with cerebellar edema and acute hydrocephalus. A 52-year-old man with history of substance abuse and hepatitis C, presented with confusion. Laboratory studies were only remarkable for a urine drug screen positive for amphetamine, cocaine, and benzodiazepine. Computed Tomography of the head showed diffuse cerebellar edema with mass effect on the fourth ventricle, dilation of third and bilateral ventricles and obstructive hydrocephalus. Brain MRI showed abnormal leptomeningeal type enhancement through bilateral cerebellum with edema changes, along with cerebellar restricted diffusion, findings reflecting PRES with significant cerebellar involvement. During ICU stay, he had progression of hydrocephalus and decline in neurologic exam despite aggressive blood pressure (BP) control, resulting to intubation and placement of external ventricular drain (EVD). BP and ICP management were essential. He gradually improved and was extubated, recovered to discharge to a rehabilitation facility after a month of hospitalization.
Discussion: Since its first description in 1996, PRES has been found to be a misnomer as irreversibility can occur, and it does not always involve posterior circulation. It is generally accompanied by hypertensive states, with underlying conditions such as hypertension, pre-eclampsia/eclampsia, renal failure, cytotoxic agent use, and autoimmune diseases. Proposed mechanisms include dysregulation of cerebral autoregulation and endothelial dysfunction. Our patient had mostly posterior fossa involvement, with significant cerebellar edema resulting in life-threatening obstructive hydrocephalus resulting with need for an EVD. In this case, airway protection, aggressive BP and ICP management, along with early recognition were key to survival.
