The mystery of masked hypertension

Connie Kilmark has always prided herself on her good health habits. The 68-year-old doesn’t smoke, exercises six times a week and loves vegetables so much she “could eat a pound and a half of broccoli at dinner.” Her decades of regular physicals showed normal blood pressure readings — inside the doctor’s office. Little did she know that her blood pressure outside the doctor’s office was dangerously high.

Then, while participating in a research study, she was surprised to get an unusually high blood pressure reading. Next came an uncontrollable nose bleed that required a full box of tissues to stanch the flow. She also started experiencing heart palpitations. An echocardiogram revealed that her heart’s left atrium was severely dilated, most likely due to years of untreated high blood pressure.

Kilmark turned to UW Health’s Advanced Hypertension Program for help and was stunned to learn that she was among the 10-12 percent of people who have masked hypertension. “When in clinic, their blood pressure is normal. But when they leave, it is elevated,” explains Heather M. Johnson, MD, a UW Health cardiologist who specializes in hypertension management.

Clues to masked hypertension

The condition is the opposite of the better-known “white coat hypertension,” where the stress of the medical setting causes falsely high blood pressures. And because of its very nature, masked hypertension, also known as reverse white coat hypertension, can be difficult to catch.

“During a primary care visit, we can sometimes see clues that this person may have masked hypertension — for example, if they have abnormal kidney labs or are experiencing chest discomfort, headaches or vision changes,” Johnson says.

While the causes are not fully known, masked hypertension is more prevalent among men, tobacco users, those who drink excess alcohol and those who have diabetes. “It might also be stress-induced,” Johnson adds.

Those who work in high-stress jobs or have a stressful home situation might be more relaxed at the doctor’s office, but their blood pressure could skyrocket as soon as they return to their usual life stressors.

That was the case for Kilmark, who works as a counselor and also cares for a daughter with autism and a 90-year-old family friend who has dementia. “When I go to a hospital or see a physician, I feel like for a minute, I don’t have to be the main grownup in the room,” she says. “There are so many people who have that kind of chronic stress — who knows how many people could be walking around with masked hypertension and not even know it.”

It’s important to catch masked hypertension because it can be just as dangerous as regular high blood pressure. “It can cause damage to the body in exactly the same way, leading to heart attacks, heart failure, stroke, kidney disease and damage to other organs,” Johnson says.

Unfortunately, Kilmark’s hypertension had gone undetected for so long that it permanently damaged her heart’s left atrium. Even after she was diagnosed, her condition was difficult to manage — she tried a dozen blood pressure medicines and reacted so severely to one that she ended up in the emergency room with uncontrollable muscle twitching.

“Dr. Johnson finally found a medication combination that is managing my hypertension and not giving me side effects,” she says. “I am so grateful for the exceptional expertise of that clinic.”

Recognizing and managing masked hypertension

Johnson shares these tips for recognizing and managing masked hypertension:

Know your numbers. “We encourage everybody to have their blood pressure checked at least once a year,” Johnson says. The goal is to be below 140/90 — anything higher is considered hypertension.

Vary the setting. “It’s important to have your blood pressure checked in the community, at home or at the pharmacy,” Johnson says. That’s also critical for anyone who has already been diagnosed with regular hypertension. You may assume that your blood pressure has improved with treatment when it’s actually elevated outside the doctor’s office, or the problem might be more severe than you and your doctor initially realize. If your doctor suspects masked hypertension, he or she will likely ask you to wear a monitor for 24 hours to check your blood pressure throughout the day.

Watch for symptoms. Most people don’t experience symptoms with hypertension, but some patients can have shortness of breath, chest discomfort, heart palpitations, headaches or vision changes. If you have any of those symptoms, talk to your doctor, even if your blood pressure seems normal.

Change your lifestyle. You can lower your blood pressure by quitting smoking, reducing alcohol consumption, exercising regularly, getting to a healthy weight, lowering your sodium intake and, when possible, reducing stress.

Kilmark wishes she had discovered her condition earlier and is now passionate about educating others about masked hypertension. “High blood pressure is something that’s not very romantic, but it can be so stealthy and dangerous,” she says. “And the damage can be irreversible."