Hypertension is called the silent killer because it typically does damage without causing symptoms. Individuals with very severe hypertension may present with visual changes, headaches, nausea, vomiting or chest pain.
Adults with normal blood pressure should have their blood pressure checked once a year. Patients with risk factors or any systolic blood pressure reading between 120 and 129 should have their blood pressure checked semiannually.
Hypertension is typically diagnosed after screening. After an elevated blood pressure reading is noted on a screening, the average of two or more measurements on at least two separate visits over a few weeks is needed to diagnose hypertension. Individuals with a blood pressure of 180/120 mm Hg or greater can be diagnosed without confirmatory readings. In addition, individuals with blood pressures equal to or greater than 160/100 mm Hg with evidence of known target end organ damage can be diagnosed without further readings.
When measuring blood pressure, make sure that the patient has been sitting quietly for 5 minutes prior to taking the blood pressure. Ideally, the blood pressure should be checked in each arm sitting, standing and lying down. It is important to utilize the correct size blood pressure cuff. Blood pressure readings between arms should be essentially the same and a discrepancy of more than 15 mm Hg indicates possible subclavian stenosis. If a small cuff is used on a larger arm the reading will be falsely elevated and if a large cuff is used on a small arm the reading will be falsely low.
When checking blood pressure make sure the patient’s legs are not crossed. Crossing the legs elevates blood pressure. In addition, when checking blood pressure make sure the patient has not had any recent caffeine or nicotine ingestion. Caffeine ingestion falsely elevates blood pressure above the hypertensive threshold in approximately 17% of patients with normal blood pressure.18
Part of the workup for hypertension should include home blood pressure monitoring. It will minimize the limitations of office-based blood pressure monitoring. Many individuals suffer from white coat hypertension, where there is an excessive rise of blood pressure in the doctor’s office due to anxiety, and measuring blood pressure in the home setting on a day-to-day basis offers advantages in more accurate diagnosis of hypertension. The machine that is used must be validated. Measurements should be taken at different times of the day. Those with cardiac dysrhythmia including atrial fibrillation should not use home monitoring as a reliable method to detect hypertension. When home blood pressure monitoring is used a minimum 12 measurements should be taken throughout the day over a period of one week.
Unattended automated office blood pressure monitoring is where no healthcare provider actually takes the blood pressure and multiple readings are taken. This is becoming a more popular way to check blood pressure and is more likely to reduce the effects of white coat hypertension.
Ambulatory blood pressure monitoring more accurately predicts target organ damage and cardiovascular events than traditional office-based blood pressure readings. This type of measurement typically occurs at 15-20 minute intervals during the day and 30-60 minute intervals at night. Ambulatory blood pressure monitoring can help the evaluation of suspected white coat hypertension, resistant hypertension, suspected episodic hypertension, evaluation of hypotension, autonomic dysfunction, and monitoring response to treatment.
Ambulatory blood pressure monitoring has many advantages. Blood pressure typically falls at night when people are sleeping. Nondipping blood pressure is when the blood pressure does not fall at least 10% during sleep. This is a strong predictor of adverse cardiovascular outcomes. Ambulatory blood pressure monitoring is a more accurate predictor of long-term cardiovascular outcomes when compared to outpatient blood pressure monitoring. Some experts suggest that ambulatory blood pressure monitoring should be the standard for evaluating blood pressure.18
After hypertension is diagnosed, it needs to be evaluated. A critical aspect of the evaluation of hypertension is to rule out and/or determine the extent of target organ damage (TOD). TOD is damage to major organs that are fed by the circulatory system. It may include damage to the heart, brain, eyes and kidneys. It is typically only noted after years of untreated hypertension. Unfortunately, sometimes hypertension goes undiagnosed for years and at the initial diagnosis TOD is noted.
The physical exam can help diagnose TOD. Evaluating the eyes with a fundoscope can pick hypertensive retinopathy. The heart should be evaluated for any evidence of enlargement of the left ventricle. This can be indicated by a displaced apical impulse or the presence of an S4 heart sound. A neurological exam may help pick up any evidence of cerebrovascular atherosclerosis or damage. Findings that indicate neurological compromise include a carotid bruit or a focal neurological defect. No specific exam finding can help detect early kidney damage secondary to hypertension and to detect renal insufficiency the use of laboratory assessment should be done.
The next step in the workup of hypertension is to assess the other risk factors. This includes an assessment of lipid levels, tobacco use, physical activity levels, body weight, central adiposity, glucose tolerance and dietary habits.
The workup should also include ruling out secondary causes of hypertension. The physical exam may provide some clues to a secondary cause of hypertension. Below are a few points about the workup that may indicate a secondary cause of hypertension.
- A bruit in the upper abdomen may point to renal artery stenosis.
- A reduced or absent femoral pulse or a reduced blood pressure in the leg (when compared to the upper extremity) may suggest coarctation of the aorta.
- Pheochromocytoma may be suggested by labile blood pressure, sweating and palpitations.
- Obstructive sleep apnea should be considered in an obese patient who complains of feeling tired. In obstructive sleep apnea it is common for a bed partner to reports snoring and periods of apnea.
- Low energy, temperature intolerance, slow or fast heart rates and sweating may suggest thyroid dysfunction.
- Hyperaldosteronism may be present if there is weakness and lab tests show low potassium levels.
- Hyperparathyroidism may be present in an individual with kidney stones.
- Subclavian artery stenosis is indicated by a mismatch in blood pressure between the arms.
Other causes of secondary hypertension include polycystic kidney disease, renovascular hypertension, urinary tract obstruction, Cushing syndrome, primary hyperaldosteronism, brain tumor, pregnancy-induced hypertension and some medications such as alcohol, cocaine and decongestants.