Hypertension, Chronic

Essentials of Diagnosis

• For conventional office-based blood pressure (BP) measurement, the American College of Cardiology and American Heart Association (ACC/AHA) suggest that

  • Normal BP be defined as < 120/80 mm Hg

  • Elevated BP, as 120–129/< 80 mm Hg

  • Stage 1 hypertension, as 130–139/80–89 mm Hg

  • Stage 2 hypertension, as ≥ 140/ ≥ 90 mm Hg

• Usually asymptomatic

• Severe hypertension: occipital headache at awakening, blurry vision

General Considerations

• Mild to moderate hypertension nearly always asymptomatic

• Severe hypertension usually due to

  • Parenchymal renal disease

  • Endocrine abnormalities

  • Renal artery stenosis

  • Drug use

  • Abrupt cessation of antihypertensive medications

• Resistant hypertension is defined as failure to reach blood pressure (BP) control in patients adherent to full doses of a three-drug regimen (including a diuretic)

• Table 11–14 summarizes reasons for failure to reach BP control

Demographics

• About 45% of adults in the United States have a BP > 140/90 mm Hg or are receiving antihypertensive treatment

• 80% are aware of their condition

• 52% of those treated have BP under control

• Incidence of hypertension increases with age

• More men than women in early life

• More women than men later in life

• More common in black Americans (up to 25%)

Symptoms and Signs

• Usually asymptomatic

• Headaches are most frequent symptom but are nonspecific

• Elevated BP

• Loud A2 on cardiac examination

• Retinal arteriolar narrowing with "silver-wiring," arteriovenous nicking

• Flame-shaped hemorrhages

• Laboratory findings usually normal

Differential Diagnosis

Primary (essential) hypertension

• "White-coat" hypertension

• BP cuff too small

Secondary hypertension

• Adrenal

  • Primary hyperaldosteronism

  • Cushing syndrome

  • Pheochromocytoma

• Renal

  • Chronic kidney disease

  • Renal artery stenosis (atherosclerotic or fibromuscular dysplasia)

• Other

  • Oral contraceptives

  • Alcohol

  • Nonsteroidal anti-inflammatory drugs

  • Pregnancy associated

  • Hypercalcemia

  • Hyperthyroidism

  • Obstructive sleep apnea

  • Obesity

  • Coarctation of the aorta

  • Acromegaly

  • Increased intracranial pressure

  • Cocaine or amphetamine use

  • Over-the-counter products (eg, dietary supplements containing yohimbine, an alpha-2 antagonist, can produce severe rebound hypertension in patients taking clonidine)

Laboratory Tests

• Hemoglobin

• Serum electrolytes and serum creatinine

• Fasting blood sugar level

  • Hypertension is a risk factor for the development of diabetes

  • Hyperglycemia can be a presenting feature of pheochromocytoma

• Plasma lipids (necessary to calculate cardiovascular risk and as a modifiable risk factor)

• Serum uric acid (hyperuricemia is a relative contraindication to diuretic therapy)

• Urinalysis

Diagnostic Studies

• ECG

• When a secondary cause is suspected, consider

  • Chest radiograph

  • ECG

  • Plasma metanephrine levels

  • Plasma aldosterone concentration, plasma renin activity

  • Urine electrolytes

General Measures

• Dietary changes (DASH diet): high in fruits and vegetables, low fat, low salt; dietary fiber seems especially important

  • For every 7 g of dietary fiber ingested, cardiovascular risk could be lowered by 9%

  • Increased dietary fiber lowers blood pressure

  • The effect of diet on blood pressure may be mediated by shifts in the microbial species in the gut, the intestinal microbiota

• Hand squeezing exercises three times a week can lower systolic blood pressure by 6 mm Hg

• Aggressive risk factor management, including consideration of statin use

• Treatment strategies for persons with diabetics and hypertension and patients with chronic kidney disease

  • Lower target BP of < 130/80 mm Hg, given high risk of cardiovascular events

  • Include ACE inhibitors or angiotensin receptor blockers as part of regimen

Medications

• Initiation of drug therapy based on level of BP, presence of target end-organ damage, and lifelong cardiovascular risk factors profile: Table 11–5, Figure 11–1

• Major risk factors include

  • Smoking

  • Dyslipidemia

  • Diabetes mellitus

  • Age > 60 years

  • Family history of cardiovascular disease

• Diuretics: Table 11–8

• Beta-adrenergic blocking agents: Table 11–9

• Renin and ACE inhibitors and angiotensin II receptor blockers: Table 11–6

• Calcium channel blocking agents: Table 11–7

• Alpha-adrenoreceptor blocking agents, sympatholytics, and vasodilators: Table 11–10

• Low-dose aspirin (81 mg orally daily)

  • Likely to be beneficial in patients older than age 50 with either target-organ damage or elevated total cardiovascular risk (> 20–30%)

  • Care should be taken to ensure that BP is controlled to the recommended levels before starting aspirin to minimize the risk of intracranial hemorrhage

  • Data do not support the routine use of aspirin for prophylaxis in low-risk patients, including those over 65 years of age

Follow-Up

• Frequent visits until BP is controlled

• Once controlled, visits can be infrequent, with limited laboratory tests

• Lipid monitoring every year

• ECG every 2–4 years, depending on initial ECG

Complications

• Stroke

• Dementia

• Myocardial infarction

• Heart failure

• Retinal vasculopathy

• Aortic dissection

• Kidney disease, including proteinuria and nephrosclerosis

When to Refer

• If BP remains uncontrolled on three concurrent medications

• If patient has uncontrolled BP and symptoms and signs of end-organ damage

When to Admit

• Consider hospitalization if patient has very high BP and symptoms and signs of a hypertensive emergency (see Hypertensive Urgencies & Emergencies) including

  • Severe headache

  • Neurologic symptoms

  • Chest pain

  • Altered mental status

  • Acutely worsening kidney disease