I HAVE A PATIENT WITH HYPERTENSION
How do I determine the cause?
Mr. U is a 48-year-old man with a BP of 155/90 mm Hg.
What is the differential diagnosis of hypertension? How would you frame the differential?
CONSTRUCTING A DIFFERENTIAL DIAGNOSIS
First, what is normal BP, and when is a patient hypertensive? The first step is accurately measuring the BP. Table 23-1 summarizes guidelines for obtaining valid BP measurements. In addition to measurements taken during office visits, devices that measure BP at home are frequently used. Patients with these devices should be encouraged to bring them to office visits to ensure their accuracy and assess proper BP measurement technique.
Table 23-1.Guidelines for measuring BP. |Favorite Table|Download (.pdf) Table 23-1. Guidelines for measuring BP.
The patient should sit with feet on the floor and back supported for > 5 minutes in a quiet room before BP measurements are taken. The patient should empty his/her bladder prior to measurement and avoid caffeine, exercise, and smoking for at least 30 minutes before measurement.
Take at least 2 measurements spaced by 1–2 minutes and additional measurements if the first 2 are quite different.
Using a bladder that is too narrow yields false high readings. Instead of the standard cuff (12–13 cm long, 35 cm wide) use an appropriate larger cuff in patients with increased arm circumference.
Use the onset of the first Korotkoff sound and disappearance of all Korotkoff sounds to identify systolic and diastolic BP values, respectively.
Do not deflate the cuff too rapidly, otherwise individual Korotkoff sounds are missed and too low a value is measured; start with a deflation rate of 2 mm/s.
Measure the heart rate by palpation and watch out for arrhythmia, which mandates repeated BP measurements.
At the first visit, measure BP in both arms and take the higher value as the reference; measure BP at 1 minute and 5 minutes after standing upright if the patient has a disorder that frequently causes orthostatic hypotension.
The 2017 American College of Cardiology–American Heart Association (ACC/AHA) Hypertension Guideline classifies BP as:
Normal: systolic BP < 120 mm Hg and diastolic BP < 80 mm Hg
Elevated: systolic BP 120–129 mm Hg and diastolic BP < 80 mm Hg
Stage 1 hypertension: systolic BP 130– 39 mm Hg or diastolic BP 80–89 mm Hg
Stage 2 hypertension: systolic BP ≥ 140 or diastolic BP ≥ 90 mm Hg
Using this definition, the prevalence of hypertension among adults in the United States is approximately 45%.
Hypertension is either primary (essential) or secondary (resulting from ...