2007

Hypertension: Initial Evaluation Critical to Successful Management

Points to Remember

• About two-thirds of individuals older than 60 years have hypertension.
• Hypertension is a major risk factor for cardiac disease, stroke, and kidney disease.
• Secondary causes of hypertension should be considered in patients with onset of hypertension at the extremes of age, in patients with sudden onset of hypertension, and when blood pressure responds poorly to drug therapy.
• A history of snoring (with or without daytime somnolence) raises the possibility of obstructive sleep apnea, a recently recognized, potentially correctable cause of hypertension.

The Challenge

The incidence and prevalence of hypertension in the general population are rising — an estimated 33% of adults are hypertensive — and hypertension is more common in older patients. An estimated two-thirds of individuals older than 60 years have hypertension. The prevalence of hypertension is even higher in African American and Hispanic patients. Hypertension is a major risk factor for cardiac disease, stroke, and kidney disease.

Goals of Initial Evaluation

The objectives for the initial evaluation of patients with hypertension are:

• To define the severity of hypertension, including the presence or absence of target organ damage.
• To determine the presence or absence of other risk factors for cardiovascular disease.
• To identify lifestyle factors that may influence blood pressure and affect prognosis.
• To search for clues to secondary causes of hypertension.
• To confirm that hypertension is sustained by repeating measurements in the office and at home.

Taking the Medical History in Hypertensive Patients

The medical history should include the known duration of hypertension, symptoms suggesting secondary causes of hypertension, and history of recent changes in weight, especially weight gain. A review of current drug treatment is important. Among drugs that may increase blood pressure are high-dose estrogens, corticosteroids, nonsteroidal anti-inflammatory agents, nasal decongestants, appetite suppressants, and cyclosporine. An assessment of smoking and dietary intake, including sodium, alcohol, saturated fat, and caffeine, should be done. Any history of over-the-counter medications, herbal remedies, analgesics, and illicit drugs (some of which may raise blood pressure or interfere with the effectiveness of antihypertensive therapy) is important. The response to and any adverse effects of previous antihypertensive therapy should be noted. Finally, psychosocial and environmental factors that may influence hypertension control and treatment compliance should be reviewed.

Conducting the Physical Examination

The initial physical examination should include the following: assessment of height and weight; ophthalmoscopic examination (especially if hypertension is severe or of new onset); evaluation for carotid and femoral artery bruits, distended neck veins, and/or an enlarged thyroid gland; examination of the heart for abnormalities in rate and rhythm; and precordial palpation for the assessment of left ventricular hypertrophy. The physical examination also includes assessment of clicks, murmurs, and third and fourth heart sounds; examination of the lungs for crackles or bronchospasm; examination of the abdomen for bruits, masses, or abnormal aortic pulsation suggesting abdominal aneurysm; and examination of the extremities for diminished peripheral arterial pulsations, including assessment of radial-femoral pulse delay, suggesting possible aortic coarctation. The latter finding would be especially important in a young patient with hypertension. In addition, the presence of peripheral edema should be noted.

Tests Before Treatment

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Routine laboratory tests recommended before initiating therapy consist of testing to determine the presence of target organ damage and other cardiovascular risk factors. These include urinalysis, complete blood cell count and blood chemistry (potassium, sodium, creatinine, fasting glucose, and serum lipids), and 12-lead electrocardiography.

Optional tests, depending on clinical circumstances, include creatinine clearance, microalbuminuria, 24-hour urinary protein, blood calcium, uric acid, glycosylated hemoglobin, and thyroidstimulating hormone. Echocardiography can be considered for assessment of left ventricular function, left ventricular mass, and left atrial size, as well as other features that might suggest diastolic dysfunction, especially in a dyspneic patient. In selected circumstances, assessment of plasma renin and aldosterone activity can be obtained if there is a question of primary aldosteronism and imaging of the renal arteries if renal artery stenosis is suspected (eg, magnetic resonance angiography or renal ultrasonography). Renal artery stenosis should be considered in older patients with resistant hypertension, any hypertensive patient with progressive renal insufficiency, or a patient with a history of "flash" pulmonary edema.

Secondary Causes of Hypertension

Additional diagnostic procedures may be indicated to search for secondary causes of hypertension. They are most appropriate in patients with onset of hypertension at the extremes of age or when the severity of hypertension suggests secondary causes. Secondary causes of hypertension also should be considered when blood pressure responds poorly to drug therapy; when the patient has a history of previously well-controlled hypertension and blood pressures begin to increase without other explanation; in a patient with advanced stages of hypertension; or in a patient with sudden onset of hypertension.

Secondary causes of hypertension are rare but potentially correctable and therefore important to recognize. Labile hypertension or paroxysms of hypertension accompanied by headache, palpitations, pallor, or perspiration suggest pheochromocytoma. Abdominal bruits are neither sensitive nor specific for renal artery stenosis, but those that lateralize to the flank or have a diastolic component suggest renovascular disease. Truncal obesity with purple striae suggests Cushing syndrome. Ahistory of snoring (with or without daytime somnolence) raises the possibility of obstructive sleep apnea, a recently recognized, potentially correctable cause of hypertension.