Asymptomatic hypertension: When does an elevated BP matter?

You are dispatched to someone’s home to pick up a patient with no complaints other than an elevated blood pressure.

How dangerous is this elevated BP and what happens to most of these patients after they get to the ED?

In my time as an EMS provider, this was not an uncommon call to run. As a medic, I once even got publicly berated by a staff member at a primary care physician’s office because we were not moving fast enough as they were concerned, “she could have a stroke!” The patient had no complaints and her systolic in the 190s didn’t even raise the eyebrows of the ED triage nurse as she promptly had us shuttle the patient to the waiting room.

So, when does an elevated BP matter in an otherwise asymptomatic patient? Is a systolic of 200 an emergency in itself? Let’s address these questions.

Acute vs. chronic hypertension

Have you ever thought about a giraffe and how it is able to perfuse its brain with its head meters above its heart? Giraffes live with extremely high blood pressures at baseline – often twice that of the normal humans – with systolics reaching into the high 200s. Giraffes have evolved protective mechanisms to avoid damaging their organs from these chronically elevated numbers that would certainly harm a human over time. One can only imagine what kind of blood pressure a brontosaurus with its 50-foot-long neck would have needed to perfuse its tennis ball sized brain.

Humans have been shown to be able to tolerate severely elevated blood pressures for short periods of time. The highest blood pressure I could find in the literature was 480/350. Of note, this was in a body builder doing heavy leg presses while actively performing a vasalva. This is a far cry from the vast majority of patients we see on the street, but it is a reminder the human body may be able to tolerate significant changes for brief periods of time.

The simple fact is that while an increased blood pressure may signify or be secondary too an emergency, often people who are asymptomatic do not require emergent intervention.

The damage from hypertension is more insidious and less of an emergent issue in the asymptomatic patient. Simply put, hypertension causes damage over time.

So, what do we need to look for in these patients? The first and most important thing is to determine if they have any symptoms. If a patient has symptoms and a significantly elevated BP, then they will require a workup and intervention in the hospital. Depending on the symptoms, this may actually represent a true emergency.

We must make note that this discussion does not pertain to special populations, such as pregnant patients, those who gave birth within the last several months, those with end stage renal disease, those with a known aneurysm (either cerebral or vascular) and pediatrics patients.

When I evaluate patients in the ED whose complaint is hypertension, I think about the three organ systems that are most often affected.

1. The brain. Does this person have a headache that started suddenly, which would be concerning for a sub-arachnoid hemorrhage? Are they having weakness, vision changes, dizziness, altered mental status or other symptoms that they may be having a stroke or other neurologic condition?

Any patient who presents to the ED for asymptomatic hypertension will receive a full neuro exam. However, if they have no neuro complaints and have a reassuring exam, I move on to the next organ system.

2. The heart. For these patients, I ask about chest pain, epigastric pain, dyspnea, nausea, vomiting and exertional symptoms. Acute coronary syndrome, heart failure and aortic dissections can certainly make people hypertensive, but generally are accompanied by other symptoms.

I will also evaluate the patient clinically for signs of heart failure, listening for rales or a murmur, examining for JVD and looking for pitting edema. Without any cardiac symptoms and a normal exam, I move onto the kidney the final organ system I assess for these patients.

3. The kidneys. We can’t quite examine the kidney, but generally, I ask if the patient is still producing urine and has a history of kidney disease, and will look for signs of edema. If all of these are negative, I will move on.

Next, I inquire about a history of high blood pressure, drug usage and medications that could be driving the patients elevated numbers. Did they forget to take their AM blood pressure pills, or recently start a new medication? This history may be important, but from an ED perspective it often won’t change my management for these patients.

For those who have chronically elevated blood pressures, lowering it too rapidly may actually cause harm and we often avoid it. The American College of Emergency Physicians 2013 guidelines on this matter do not advocate for routine testing to include lab work or ECGs for most patients who have asymptomatic hypertension. They also do not advocate for the lowering of blood pressure in the emergent setting for these patients. They do, however, advise helping these patients to establish follow up to prevent long term consequences should their blood pressures remain elevated. For most of these patients, after a history and physical exam, including a detailed neuro assessment, we will discharge them home with a plan for outpatient follow-up.

Prehospital management of asymptomatic hypertension

So how does this play a role in the EMS world? Obviously, follow your local protocols when it comes to managing these patients, but it’s important to keep in mind, for a patient without symptoms and a normal exam, whose only complaint is high blood pressure, may not be an emergency.

Some of these patients may even be appropriate for POV transport to the hospital or for a discussion with med control about whether they need to be evaluated in the ED at all.