Differentiating between various forms of hypertension presents challenges for physicians
Diagnosis is heterogeneous and can be key to distinguishing the differences.
When it comes to the differentiation and diagnosis of hypertension, referred to colloquially as “the silent killer,” physicians and cardiologists must be aware that hypertension and elevated BP are not always linked, and that there are various forms of hypertension.
“Hypertension is more than just elevated BP,” George L. Bakris, MD, professor of medicine and director of the Hypertensive Diseases Unit in the department of medicine at the University of Chicago Pritzker School of Medicine, said in an interview. “When a patient presents with elevated BP, they do not necessarily have hypertension. Elevated BP could be transient or persistent.”
Although high BP is a manifestation of hypertension, hypertension is a genetically mediated disease, Bakris told Cardiology Today.
George L. Bakris, MD, said distinguishing between the numerous forms of hypertension is essential to proper care.
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George L. Bakris, MD
“It is important to not only educate health care professionals about the difference between the two, but to also convey this message and prevention efforts to our patients,” said Bakris, who is the current president of the American Society of Hypertension and an Editorial Board member for Cardiology Today.
Rising rates of high BP are seen across the country, but health care professionals are also seeing diagnosis of hypertension in younger populations compared with years past. According to the most recent results of the National Health and Nutrition Examination Survey, 29% of US adults aged at least 18 years have hypertension — a number that equates to about 70 million. Globally, 26.4% of the adult population (972 million) had hypertension more than a decade ago, and the number of adults with hypertension is expected to increase to 1.56 billion in 2025, according to a study by Kearney and colleagues that was published in The Lancet.
It is now more important than ever to properly delineate the difference between spiked BP, diagnosable hypertension and to distinguish between the various forms. Cardiology Today spoke with several experts in the arena on this topic.
Common forms of hypertension
Coined essential hypertension nearly 100 years ago, primary hypertension is typically a genetic disease, with susceptibility increasing based on one’s environment.
“The term essential hypertension is no longer in vogue; it evolved in the early 1920s or 1930s with the notion that older people who were living longer had elevations in BP,” Bakris said. “Back then, the doctors felt it was ‘essential’ because their pipes were getting rusty and needed more infusion, hence the term essential. Now, though, we know that is not true, so it is termed primary hypertension.”
Primary hypertension is seen approximately 95% of the time, ranking as the most commonly occurring form of hypertension, and refers to elevated BP from multiple abnormalities in the regulatory functions, according to Shawna D. Nesbitt, MD, MS, associate professor of internal medicine, division of cardiology hypertension section, at the University of Texas Southwestern. These abnormalities may vary from dysfunction in calcium, potassium or sodium levels, vascular contractions, hormonal elevations and central nervous system stimulations.
“Primary hypertension is pervasive across all races and both genders,” Nesbitt said. “While treatable, primary hypertension is not curable, and the goal of treatment is to prevent the key consequences of elevated BP such as kidney disease, stroke or MI.”
Secondary hypertension, however, is second to primary hypertension and occurs when the patient has no family history of hypertension, with no obvious reasons for a diagnosis.
“Usually, these people have secondary hypertension because it is secondary to an endocrine problem or a renal problem,” Bakris said.
William B. White, MD, professor and division chief of hypertension and clinical pharmacology at the Pat and Jim Calhoun Cardiology Center, University of Connecticut School of Medicine, said secondary hypertension refers to a discernible underlying cause of BP elevation that may include, but is not limited to, renal artery stenosis, a benign tumor on the adrenal gland, primary aldosteronism, pheochromocytoma, hyperthyroidism or the use of BP-raising drugs.
If a secondary condition is diagnosed and curable, then removing this cause is typically associated with marked improvement in hypertension.
Transient forms of hypertension
According to Joel Handler, MD, clinical leader for the Kaiser Permanente national hypertension program and the Kaiser Permanente Southern California hypertension program, a common problem for practitioners is clinical uncertainty.
“Many factors are responsible for BP measurement variability; among those are white-coat, reactive and masked hypertension,” Handler said.
White-coat hypertension is a form that occurs when the patient’s BP in a medical environment, such as a physician’s office or hospital setting, is more than 10 mm Hg to 15 mm Hg higher than it is in other environments. This form of hypertension carries less CV risk than true hypertension, but that risk appears to be intermediate and possibly predictive of the future development of true hypertension, according to Handler.
In addition, patients with treated hypertension can still have a white-coat effect. One confounding factor with white-coat form is that the variability in the response of the BP is not predictable, making it extremely hard to measure and treat.
Physicians may have also heard the term reactive hypertension, or reactive elevations or spikes in BP, which is caused by a stimulus. Bakris said, however, that there is no such thing as a diagnosed reactive form of hypertension.
“This is a prime example of where the definitions of hypertension and high BP get muddled,” he said. “Blood pressure becomes elevated during a stressful situation.”
This form is often interchanged with white-coat hypertension, given that it occurs in reaction to a setting or event, according to Nesbitt. It is more commonly seen in patients who experience pain after surgery, anxiety or psychiatric disorders but do not have diagnosed hypertension.
“Importantly, we shouldn’t be quick to give BP medication because there may be an underlying condition that is a stimulation of the sympathetic nervous system,” she said.
Physicians should first do a full workup, including a genetics evaluation, and monitor the patient using a 24-hour ambulatory device, if necessary.
Typically seen among the black population with kidney disease or among young people with no history of high BP, masked hypertension is the inverse of white-coat hypertension and is described by normal BP readings in the presence of the health care professional and elevated out-of-office BPs, according to Handler.
“Similar to white-coat hypertension, masked hypertension appears to be an intermediate risk factor,” he said. “Though masked hypertension is more worrisome in the presence of target organ damage such as chronic kidney disease, studies have not been performed to show benefit from antihypertensive drug treatment.”
Nesbitt said each one of these forms of hypertension are all very different, so to define white-coat vs. mask vs. reactive hypertension may be difficult, but the most important diagnostic tool to differentiate these forms is an ambulatory BP monitor or home BP monitoring.
Intermingled hypertension in-depth
Another form of hypertension that is more antiquated, according to Bakris, is accelerated hypertension. This form refers to a patient who was diagnosed with primary hypertension that was controlled at one point for a period of time, and now the patient’s BP is elevated despite no changes in medication or lifestyle. The patient experiences progressive increases in BP that can top out at extremely high levels of 240 mm Hg/120 mm Hg in a relatively short period of time.
“If you have a patient with this situation, you have to evaluate whether there was a change in dietary intake, such as increased salt consumption or weight changes. If those can be ruled out, then look immediately at secondary causes such as alternative health issues,” Bakris said. “Accelerated hypertension is not uncommon among people with kidney disease or changes in their lifestyle.”
Accelerated hypertension is often intermingled with malignant hypertension, White said. Patients may present with acute retinal hemorrhages, papilledema of the optic disc, acute pulmonary edema and hypertensive encephalopathy.
“The term malignant hypertension was used by pathologists who noted that these patients have acute target organ injury associated with fibrinoid necrosis of the wall of an artery,” he said. “This is a serious and life-threatening condition.”
Malignant hypertension is a “distinctly unusual” form of hypertension, according to Bakris, and is typically seen in a patient with a markedly elevated BP reading of 170 mm Hg/110 mm Hg or higher. This form of hypertension is more common in patients aged 50 years and older.
Similarly, patients who present with elevated BP but are asymptomatic may have hypertensive urgency. Hypertensive urgency is a situation in which BP is more than 180 mm Hg to 200 mm Hg systolic and/or more than 110 mm Hg to 120 mm Hg diastolic. The cause for concern would be that if BP goes much higher, the patient may experience an ill effect, according to John D. Bisognano, MD, PhD, director of medicine and cardiology at University of Rochester Medical School, New York.
“This is different than a hypertension emergency, a term often used interchangeably with malignant hypertension, where there is actual damage to an organ occurring because of the elevated BP,” Bisognano told Cardiology Today.
The difference between hypertensive emergency and urgency, which share similar BP elevations, is active target organ damage, such as stroke, encephalopathy, acute coronary ischemia, acute pulmonary edema, aortic dissection, blindness and acute renal failure.
Isolated systolic hypertension, also known as systolic hypertension, is more commonly seen in people aged older than 60 years who have stiffened vessels with a BP reading of 140 mm Hg/90 mm Hg. The systolic number is elevated; the diastolic number is not.
“It is evident that the systolic BP is a more potent risk factor than the diastolic BP for predicting stroke, HF and other consequences of hypertension,” White told Cardiology Today. “This condition is, therefore, serious if left untreated.”
Resistant hypertension is classically defined as having hypertension that persists despite the use of three or more pharmacologically complementary antihypertensive drugs at maximally tolerated doses, one of which includes a diuretic. BP reading is also typically more than 140 mm Hg/90 mm Hg in an otherwise healthy patient. For this type of patient, renal nerve ablation may be warranted, along with a review of other medications.
“This is actually fairly common in practice and is an issue if the BP remains elevated for a prolonged period of time,” White said. “Resistant hypertension is often associated with secondary hypertension.”
Pseudo-hypertension describes a rare condition in which the blood vessel walls are so stiff that the BP cuff cannot compress the artery without exerting very high levels of external pressure. BP values are often much higher than what would be detected via catheter and do not actually reflect the actual BP measurement in the artery.
It was coined in the late 1980s and early 1990s, according to Bakris, and is also seen exclusively in the elderly with stiff vessels but who also experience various adverse effects from the elevated BP.
“Pseudo-hypertension is not used much anymore, certainly not in the medical literature, because research has shown that those people have isolated systolic hypertension,” he said. “It has become a passé term.”
Diagnosis and treatment efforts
According to White, the diagnoses of all of these forms of hypertension are relatively heterogeneous.
“We would like to see enhanced use of out-of-office monitoring, thought to improve diagnostic precision, conducted by both self-BP monitoring, as well as 24-hour monitoring when appropriate,” he said.
Proper diagnosis of any of the aforementioned forms of hypertension should not be based on a single reading. A patient’s age, weight, ethnicity, family history, smoking status and other lifestyle factors can change a physician’s perspective when determining which form of hypertension the patient may have, according to Nesbitt.
“Physicians need to approach each patient as an individual who may have a unique form of hypertension and listen for the various cues that relate to the specific types of hypertension,” she said. “Listening will help you learn much more about how to select which test to perform or not perform based on their examination.”
It is important to actively evaluate and treat hypertension in all populations, regardless of age, ethnicity and gender, and not write elevated BPs off to a white-coat effect, according to Bisognano.
“Never miss the opportunity to treat a patient’s hypertension,” he said. “If their numbers are above the goals, reinforce a healthy lifestyle, but check their BP again soon.” – by Tara Grassia
For more information:
- Chobanian A. Hypertension. 2003;42:1206-1252.
- Egan B. JAMA. 2010;303:2043-2050.
- Flack J. Hypertension. 2010;56:780-800.
- Kearney P. Lancet. 2005;365:217-223.
Disclosures: Dr. Bisognano is a consultant for CVRx. Dr. Nesbitt is a speaker/consultant for Novartis, a consultant for Daiichi Sankyo, a speaker for Boehringer Ingelheim, and a speaker for Gilead. Drs. Bakris, Handler and White report no relevant financial disclosures.