2362 Hypertensive brainstem encephalopathy; profound isolated brainstem neuroimaging changes in a patient with intractable hypertension and renal dysfunction

Hypertensive encephalopathy is a neurological emergency characterised by breakdown of cerebral autoregulation resulting in symptoms ranging from headache to seizures, reduced consciousness and death. Posterior reversible encephalopathy syndrome (PRES) is a well-recognised hypertensive encephalopathy variant, often caused by severe hypertension, but also described with use of immunosuppressive medications and in cases of eclampsia, uraemia and sepsis with parieto-occipital predilection on magnetic resonance imaging (MRI). A more recently recognised variant of hypertensive encephalopathy is Reversible Hypertensive Brainstem Encephalopathy (RHBE). RHBE presents similarly to PRES however it is radiologically confined to the brainstem without supratentorial involvement and is exclusively reported in cases of severe hypertension, often in association renal impairment. We report a case of RHBE in a 32 year-old male who presented with reduced consciousness, fever and seizure episode requiring intubation, in the context of known renal impairment and severe hypertension. The MRI demonstrated profound changes isolated to the brainstem with T2 and Diffusion Weighted Imaging hyperintensity associated with increased signal on Apparent Diffusion Coefficient imaging; suggestive of diffuse brainstem vasogenic oedema. This case posed an early diagnostic dilemma given the similar features seen in both infectious rhombencephalitis and central pontine myelinolysis. The hallmark features of RHBE are clinico-radiological dissociation along with rapid normalisation of neuroimaging with appropriate blood pressure control and supportive measures; both prominent findings in this patients case. We aim to raise clinician awareness of RBHE as early recognition and management is vital in preventing permanent disability and in the avoidance of potentially harmful misguided treatments.