Hypertensive emergency: a case-based approach

The presentation

Imagine an adult who knows their blood pressure has been high but has not been taking their tablets for a while. Over the last day they have developed a severe, pounding headache that will not shift, along with blurred vision and a feeling of being generally very unwell. They may feel breathless, have chest pain, feel sick, or seem confused and drowsy. When their blood pressure is checked it is extremely high. This is very different from the usual picture of high blood pressure, which most often causes no symptoms at all and is picked up on a routine check. The combination of a very high reading together with symptoms such as a severe headache, visual changes, chest pain, breathlessness or confusion is the pattern that should ring alarm bells and prompt emergency help.

Why very high blood pressure can be dangerous

Blood pressure is the force of blood pushing against the walls of the arteries. Kept mildly high over years it slowly damages the heart, kidneys, eyes and brain — which is why it is treated. But when the pressure rises very high very quickly, it can start injuring these organs within hours. The strain can trigger a stroke or bleeding in the brain, put dangerous stress on the heart causing chest pain or heart failure, injure the kidneys, or damage the delicate blood vessels at the back of the eyes, harming vision. Doctors call this a hypertensive emergency because organ damage is either happening or about to happen. It needs careful lowering of the pressure in hospital, done gradually and safely, because dropping it too fast can also be harmful — another reason it is a job for the emergency team.

When to call 999

Call 999 or go straight to A&E if someone with very high blood pressure also has warning symptoms: a sudden or severe headache that will not go away, blurred or lost vision, chest pain or tightness, breathlessness, weakness or numbness on one side, difficulty speaking, confusion, drowsiness, fits, or severe nosebleeds that will not stop. Any of these with a very high reading may mean the pressure is damaging an organ. Do not wait to see if it settles, and do not take extra doses of blood pressure medicine at home to try to force the reading down quickly — this can be dangerous. While waiting for help, keep the person calm and sitting quietly, note the reading and their symptoms, and tell the call handler both the blood pressure number and the warning signs you have noticed.

High blood pressure that is not an emergency

Most high blood pressure is not an emergency. Often it causes no symptoms and is found on a routine check, and it is managed steadily over weeks and months with lifestyle changes and medicines through your GP. Even a single high reading is usually not a crisis — blood pressure naturally goes up and down, and readings can be raised by stress, pain, caffeine or a rushed appointment. If you get a high home reading but feel well, it is reasonable to rest, recheck after a short while, and contact your GP or NHS 111 for advice rather than rushing to hospital. The key difference is symptoms: a very high reading with a severe headache, visual changes, chest pain, breathlessness or confusion is an emergency, whereas a high reading in someone who feels well is a matter for prompt but routine review.

The safe pathway

The practical rule is to look at how the person is, not just the number. If blood pressure is raised but they feel completely well, arrange a proper recheck and speak to your GP or NHS 111 about reviewing treatment — this is important but not an emergency. If the reading is very high and there are any warning symptoms — severe headache, blurred vision, chest pain, breathlessness, weakness, difficulty speaking, confusion or fits — call 999 or go to A&E immediately. Taking blood pressure medicines regularly as prescribed, keeping up reviews, and not stopping them suddenly all help prevent a crisis in the first place. Hypertensive emergencies are uncommon, but because organ damage can happen fast, recognising the warning pattern and letting the emergency team lower the pressure safely is always the right choice.