Reversible brainstem hypertensive encephalopathy (RBHE): Clinicoradiologic dissociation

We report two cases of reversible brainstem hypertensive encephalopathy (RBHE) with unusual magnetic resonance (MR) findings. Patient 1, an 85-year-old man without a history of hypertension, developed acute severe hypertension and mild consciousness disturbance as the only symptoms. Patient 2, a 46-year-old man with an untreated hypertension, presented with extremely high blood pressure and general fatigue, vertigo, and mild dysarthria as the initial manifestations. In these patients, fluid-attenuated inversion recovery (FLAIR) and T2-weighted MR images revealed diffuse hyperintensities in the brainstem. Diffusion-weighted imaging (DWI) findings were normal, and apparent diffusion coefficient (ADC) values were increased in the brainstem. The supratentorial regions were largely spared, and mildly diffuse hyperintensities were noted in the white matter. There were no accompanying changes in the occipital lobe and cerebellum. The lesions completely resolved after stabilization of blood pressure. The normal DWI findings and high ADC values were consistent with vasogenic edema due to severe hypertension. The characteristics of RBHE are a very high blood pressure, mild clinical and neurologic symptoms, rapidly improved MR findings after initial treatment with the control of hypertension, and a marked clinicoradiologic dissociation.