Approach to hypertension: Clinical sciences

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Introduction0:00–0:38

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.

Unstable patient0:38–2:35

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.

Stable patient2:35–4:06

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.

Review medication list4:06–4:57

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.

Renal causes4:57–5:43

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.

Endocrine causes5:43–8:03

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.On the other hand, your patient might complain of muscle cramps, weakness, polyuria, and polydipsia, which are often associated with lab results that show low potassium levels and high bicarbonate levels.
These findings could indicate hyperaldosteronism. To check for this, order plasma aldosterone concentration or PAC, and plasma renin activity or PRA, and use the results to calculate the PAC/PRA ratio.
If the ratio is greater than 20 to 1, suspect primary aldosteronism. Next, determine if the criteria for diagnosis of primary aldosteronism are met.
These include hypertension, hypokalemia, PAC greater than 20 nanograms per milliliter, and PRA that is below the lower limit of normal, or even undetectable.
If all of these criteria are met, diagnose primary aldosteronism. Next, if your patient has a history of depression and weight gain, and the physical exam reveals moon facies, central obesity, and striae, consider Cushing syndrome.
To confirm, order an overnight dexamethasone suppression test, and if the serum cortisol is greater than 1.8 micrograms per deciliter, diagnose Cushing syndrome.
Finally, if history findings include headache, sweating, tachycardia, and palpitations, and the physical exam reveals orthostatic hypotension with or without severe hypertension, consider pheochromocytoma.
Next, order plasma free metanephrines, and if they are elevated, diagnose pheochromocytoma. Alright, now that you’ve ruled out the most common endocrine causes of hypertension, let’s assess the cardiovascular ones.

Cardiovascular causes8:03–9:20

First, let’s say your patient is a young adult, and the physical exam reveals decreased lower extremity pulses as well as a blowing systolic murmur at the left interscapular space.
If these signs are present, consider coarctation of the aorta and order imaging like a transthoracic echocardiogram or a thoracoabdominal CT scan.
If imaging reveals a narrowing of the aortic arch at the isthmus, you can confirm the diagnosis of coarctation of the aorta.Sometimes, the patient’s history can reveal a sudden onset of hypertension, hypertension that is resistant to treatment with antihypertensives, and atherosclerotic disease.
If these history findings are associated with an abdominal bruit on auscultation, consider renovascular hypertension. At this point, you should order a duplex ultrasound of the renal arteries.
If the ultrasound shows arterial narrowing, the underlying cause of hypertension is renal artery stenosis.Alright, if you rule out medication-induced hypertension, as well as renal, endocrine, and cardiovascular causes of hypertension, one last category to assess is sleep disordered breathing.

Sleep-disordered breathing9:20–9:57

In this case, the patient will typically report a history of snoring, respiratory pauses during sleep, or daytime somnolence.
Additionally, if the physical exam reveals obesity, you should order a polysomnogram. If the results reveal an abnormal apnea-hypopnea index, diagnose obstructive sleep apnea.if you rule out medication-induced hypertension, the most common renal, endocrine, and cardiovascular causes of hypertension, and sleep-disordered breathing, think of essential hypertension.

Essential hypertension9:57–10:46

In this case, a physical exam reveals isolated hypertension, which confirms the diagnosis.Now, here’s a clinical pearl to keep in mind!
The vast majority of hypertension is essential. So, it makes sense to start antihypertensive treatment once hypertension is confirmed, even before assessing for secondary causes.
However, if the patient doesn't respond well to treatment, you should investigate secondary hypertension to identify any underlying causes.Alright, as a quick recap… Hypertension is defined as having systolic blood pressure above 130 or diastolic blood pressure above 80 on two separate occasions.

Review10:46–11:35

Once hypertension is confirmed, investigate underlying causes. If you rule out medication-induced hypertension, assess for the most common renal causes, like polycystic kidney disease, as well as endocrine causes, such as hyperthyroidism, primary aldosteronism, Cushing syndrome, and pheochromocytoma.
If you rule out renal and endocrine causes, look into cardiovascular causes like coarctation of the aorta and renal artery stenosis.
Finally, check for sleep-disordered breathing as it is also associated with hypertension. If you find no