Background: Acute elevations in systemic blood pressure are associated with a wide array of manifestations involving the central nervous system, ranging from no overt neurologic symptoms or signs to catastrophic scenarios like intracerebral hemorrhage (ICH). Very little is known regarding the determinants of this clinical variability. In this study we determined clinical and imaging features of neurologically asymptomatic hypertensive crisis patients, patients with hypertensive ICH and hypertensive posterior reversible encephalopathy syndrome (PRES).
Methods: Magnetic resonance imaging (MRI) data was prospectively collected from a consecutive series of patients admitted to the emergency department with a diagnosis of hypertensive urgency or emergency but no neurologic symptoms. Features of small vessel disease (lacunes, microbleeds, perivascular spaces, white matter hyperintensities) were rated and small vessel disease burden score was determined. These features, together with clinical characteristics, were compared to those of patients presenting with hypertensive ICH and PRES.
Results: Patients with hypertensive ICH (n=58) comprised the group with the oldest age, longest duration of hypertension and highest burden of vascular risk factors, while the PRES group (n=9) signified the youngest group with short duration of hypertension and minimum number of vascular risk factors. The neurologically asymptomatic hypertensive crisis group (n=51) showed an intermediary phenotype not only with respect to these clinical characteristics, but also in terms of small vessel disease features. Multivariate analyses revealed advanced age (p=0.009), cerebral microbleeds (p<0.001) and small vessel disease burden (p=0.019) to be related with cerebral hemorrhage rather than asymptomatic hypertensive crisis or PRES.
Conclusion: The clinical phenotype in the setting of an acute hypertensive episode depends on specific clinical and imaging features. PRES occurs in young brains not accustomed to chronic hypertension, while the episode results in ICH in old patients with a high small vessel disease burden and remains asymptomatic among patients devoid of such characteristics.