Essential hypertension: Clinical sciences

Essential hypertension is a chronic condition that occurs when an individual’s blood pressure is persistently elevated, without an identifiable cause. It’s a significant contributor to the development of atherosclerotic cardiovascular disease, or ASCVD. Diagnosis is based on the presence of ASCVD risk factors, ruling out secondary causes with screening labs, and classifying your patient’s blood pressure readings into one of the three groups: Elevated Blood Pressure, formerly known as pre-hypertension, with a systolic blood pressure between 120 and 129 and diastolic blood pressure less than 80 mmHg; Stage 1 hypertension with a systolic blood pressure between 130 and 139 or diastolic blood pressure between 80 to 89 mmHg; or Stage 2 hypertension with a systolic blood pressure greater than or equal to 140 or diastolic blood pressure greater than or equal to 90 mmHg.

Now, if you suspect essential hypertension, perform an ABCDE assessment to determine if the patient is stable or unstable. If unstable, stabilize their airway, breathing, and circulation. Additionally, obtain IV access, provide supplemental oxygen, and put them on continuous vital sign monitoring including blood pressure, heart rate, and pulse oximetry. Next, proceed with a focused history and physical examination and obtain CMP, troponin, and urinalysis. Also, don't forget to order an ECG and chest X-ray. Together, these will help you identify target organ damage.

Now, your patient might report vision changes, headache, shortness of breath, chest pain, or back pain. Their physical exam may reveal a systolic blood pressure of 180 or a diastolic blood pressure of 120 or greater. Additionally, the exam might reveal altered mental status, respiratory crackles, or decreased peripheral pulses.

As for labs, you may see an elevated creatinine on CMP, an elevated troponin, and proteinuria on the urinalysis. The ECG might show ST segment changes, atrial fibrillation, or left ventricular hypertrophy, while the chest X-ray may reveal a widened mediastinum* or pulmonary edema**.

These findings indicate target organ damage. The combination of severely elevated blood pressure, often with systolic blood pressure over 180 or diastolic blood pressure over 120, and evidence of target organ damage indicates Hypertensive Emergency.

Treatment consists of IV antihypertensive medications, such as non-selective beta-blockers, like labetalol; vasodilators, like hydralazine; or angiotensin-converting enzyme inhibitors, or ACE inhibitors, like enalapril.

Here’s a high yield fact! When there’s severely elevated blood pressure without evidence of target organ damage, that’s Hypertensive Urgency. In these patients, blood pressure can be reduced gradually with oral antihypertensives.

Okay, let’s go back and look at stable patients. If your patient is stable, proceed with a focused history and physical exam. Your patient might be asymptomatic, or could report non-specific symptoms like nose bleeds or headaches. They may also have ASCVD risk factors. These include weight gain, physical inactivity, and tobacco use, but also comorbidities like coronary artery disease, heart failure, hyperlipidemia, diabetes, and chronic kidney disease. Additionally, there might be a positive family history of hypertension. Finally, if physical exam reveals a blood pressure greater than 120 over 80 mmHg, you should suspect either elevated blood pressure or hypertension.

Ok, now that you suspect this, order screening labs, which include a TSH, CBC, CMP, lipid panel, and urinalysis, as well as an ECG. These will help rule out secondary causes of hypertension, such as renal parenchymal disease like polycystic kidney disease; vascular disorders like renal artery stenosis or coarctation of the aorta; obstructive sleep apnea; or side effects from medications.

If it’s not secondary, TSH will typically be normal, while the remaining labs might reveal abnormalities due to comorbidities. For example, CBC may show anemia due to chronic kidney disease; while CMP might reveal an elevated creatinine, indicating kidney injury, or elevated glucose, indicating diabetes. Additionally, lipid panel may show elevated low-density lipoprotein, elevated triglycerides, as well as decreased high-density lipoprotein, which indicates hyperlipidemia; while urinalysis might show proteinuria,suggestive of kidney injury. Finally, the ECG can help you evaluate cardiac comorbidities, like left ventricular hypertrophy or poor contractility due to ischemic heart disease.

After ruling out secondary causes, your next step is to classify the patient’s blood pressure. If systolic blood pressure is between 120 and 129 and diastolic blood pressure is less than 80, diagnose Elevated Blood Pressure. In this case, be sure to treat pre-existing comorbidities and encourage lifestyle modifications, such as weight loss, a low-sodium heart-healthy diet, like the Dietary Approaches to Stop Hypertension, or DASH diet, an exercise routine, and reducing alcohol intake. Of these interventions, a low-sodium heart-healthy diet will result in the biggest reduction in blood pressure.