Approach to hypertension: Clinical sciences

Hypertension is defined as a systolic blood pressure greater than or equal to 130 millimeters of mercury, or a diastolic blood pressure greater than or equal to 80 millimeters of mercury, that’s measured on two separate occasions. Most cases of hypertension are primary or essential, meaning there’s no identifiable underlying cause. However, in some cases, hypertension can be secondary to an underlying cause, such as certain medications, renal, endocrine, or cardiovascular conditions, and sleep-disordered breathing.

Now, if you suspect hypertension, you should first perform an ABCDE assessment to determine if your patient is unstable or stable. If the patient is unstable, stabilize the airway, breathing, and circulation. Next, obtain IV access and put your patient on continuous vital sign monitoring, including blood pressure, heart rate, and pulse oximetry. Finally, if needed, provide supplemental oxygen.

Now here’s a high-yield fact to keep in mind! A hypertensive crisis occurs when the systolic pressure is above 180, or the diastolic pressure is above 120 millimeters of mercury. Now, the term hypertensive crisis includes both hypertensive emergency and hypertensive urgency. The difference between the two is that hypertensive emergency is associated with symptoms of imminent end-organ damage, such as stroke, retinal hemorrhage, papilledema, myocardial infarction, or acute kidney injury To prevent end-organ damage, you must immediately treat your patient with an IV antihypertensive, such as nitroprusside, to lower the blood pressure, but making sure it doesn’t exceed a 10 to 20% decrease over the first hour, and then gradually over 24 hours, in order to avoid cerebral and myocardial hypoperfusion.

On the other hand, hypertensive urgency may present with symptoms like headache or chest pain, but is not associated with end-organ damage yet, although it also poses serious risk! For treatment here, you can give an oral antihypertensive, such as a beta blocker or an ACE inhibitor, with the goal of lowering blood pressure gradually over 24 hours, so as to minimize the risk of rapid drops in perfusion to vital organs.

Now that we’ve addressed how to treat an unstable patient, let’s go back to the ABCDE assessment and discuss the stable ones. If your patient is stable, first obtain a focused history and physical examination.

Your patient may report headaches, palpitations, or weakness, or they may have no symptoms at all! Also, there might be risk factors like tobacco or alcohol use, as well as physical inactivity and obesity. Physical examination reveals a systolic blood pressure greater than or equal to 130 millimeters of mercury, or a diastolic blood pressure greater than or equal to 80 millimeters of mercury.

At this point, you should consider hypertension, and have your patient return for a repeat blood pressure measurement at a follow-up appointment. If the systolic pressure is again 130 or higher or the diastolic pressure is 80 or higher, you can diagnose hypertension.

Now, here’s a clinical pearl to keep in mind! Your patient's blood pressure measurements might be high in the office, but normal elsewhere, a phenomenon known as whitecoat hypertension. On the other hand, the blood pressure measurement might be low in office, and high elsewhere, what's referred to as masked hypertension. In either case, you can use an ambulatory blood pressure monitor to track blood pressure changes in different environments and eventually rule out or confirm the diagnosis.

Alright, now that you’ve diagnosed hypertension, review your patient’s medication list, because some medications can induce hypertension. Ask if they use stimulants like caffeine, nicotine, or decongestants. Also, ask about NSAIDs, glucocorticoids, or oral contraceptives. If your patient takes any of these medications, consider adjusting the dose or stopping them if possible and see if their hypertension resolves. If it does, diagnose medication-induced hypertension.

However, if no causative medications are identified, consider if you should assess your patient for other secondary causes. This will involve ordering labs, including BMP and urinalysis.

Okay, first, let’s start by assessing for renal causes. Your patient may report frequent UTIs and a family history of autosomal dominant polycystic kidney disease, while physical exam might reveal increased abdominal girth. Additionally, the BMP usually shows elevated serum creatinine, and urinalysis would typically be positive for hematuria and proteinuria. All these findings are highly suggestive of renal parenchymal disease, so order a renal ultrasound. If the ultrasound shows multiple renal cysts, diagnose polycystic kidney disease.

Next, if you rule out renal causes, evaluate your patient for possible endocrine causes of hypertension. In these individuals, history typically reveals heat intolerance, weight loss, and palpitations; while the physical exam findings typically include warm, moist skin and a tremor. In this case, consider hyperthyroidism, and order a TSH and free T4. If the TSH is low and the free T4 is elevated, diagnose hyperthyroidism.