Isolated cerebellar involvement in posterior reversible encephalopathy syndrome.

BACKGROUND: Posterior reversible encephalopathy syndrome (PRES) is a serious and increasingly recognized disorder in humans. However, isolated cerebellar involvement in PRES is extremely uncommon. In this study, we sought to investigate its clinical and radiological features by describing a cohort of cases with PRES and isolated cerebellar involvement.

METHODS: We report 2 patients with PRES with only cerebellar involvement and identified additional 9 cases using the PubMed database with the MeSH terms "posterior reversible encephalopathy syndrome", "hypertensive encephalopathy", "hypertension", "cerebellum", "encephalopathy", and "magnetic resonance imaging". We then collectively analyzed the clinical and imaging characteristics of these 11 cases.

RESULTS: The average age was 28years, with 8 male and 3 female patients. All cases had severe acute hypertension and T2 hyperintensity on MRI exclusively centered within the cerebellum. Of 11 patients, 7 had hypertensive retinopathy, a favorable clinical course with only antihypertensive treatment, and resolution of the cerebellar lesions on follow-up imaging. A total of 5 of the 11 patients received external ventricular drainage due to obstructive hydrocephalus and only 2 of the 11 had a seizure.

CONCLUSIONS: Isolated cerebellar involvement in PRES may be a unique variant that affects younger, male cases with severe acute hypertension and hypertensive retinopathy, but not necessarily seizure. Most patients have full recovery after fast control of blood pressure. Awareness of atypical neuroimaging features in PRES is critical for appropriate treatment.