Very high blood pressure can predispose to acute complications including stroke, heart attack, heart failure, aortic dissection, kidney failure, and damage to the retina (the back of the eye).

A hypertensive crisis is said to occur when the systolic blood pressure exceeds 180-200 mmHg and/or diastolic blood pressure exceeds 120 mmHg. Patients with a BP in this range should be treated immediately in the ER, regardless of whether they have any symptoms.

However, hypertensive emergencies can occur with even modest elevations in blood pressure when accompanied by worrisome symptoms (i.e. symptoms suggestive of impending or progressive organ damage). Patients with elevated BP who are experiencing chest pain, shortness of breath, severe headache, acute changes in vision, slurred speech, acute confusion, etc. should proceed to the ER immediately via ambulance.