Elevated blood pressure — defined as an intermittent or sustained increase in blood pressure exceeding 140/90 mm Hg — is more common in men than women and affects twice as many Blacks as Whites. Despite being common, this sign is often ignored by patients because it cannot be seen or felt. However, its causes can be life-threatening.

Gender cue

• Hypertension is reported to be two to three times more common in women taking hormonal contraceptives compared to those not taking them.

• Women aged 35 and older who smoke cigarettes should be strongly encouraged to stop smoking.

• Women who continue to smoke should be discouraged from using hormonal contraceptives due to increased risk of hypertension.

Onset of elevated blood pressure

• Elevated blood pressure may develop suddenly or gradually.

• A sudden, severe rise in pressure exceeding 180/110 mm Hg may indicate a life-threatening hypertensive crisis.

• Even a less dramatic rise can be equally significant if it signals:

  • Dissecting aortic aneurysm

  • Increased intracranial pressure

  • Myocardial infarction

  • Eclampsia

  • Thyrotoxicosis

Causes of elevated blood pressure

• Usually associated with essential hypertension.

• Can result from:

  • Renal or endocrine disorders

  • Treatments affecting fluid status (e.g., dialysis)

  • Adverse drug effects

  • Ingestion of large amounts of certain foods, such as black licorice and cheddar cheese, which may temporarily elevate blood pressure.

• Sometimes elevated readings may reflect inaccurate blood pressure measurement.(See also Ensuring Accurate Blood Pressure Measurement, page 96.)

Note: Careful measurement alone is insufficient; readings must be compared with the patient's baseline and serial readings may be necessary.

Pathophysiology of elevated blood pressure

Blood pressure depends on cardiac output, peripheral resistance, and blood volume. The regulatory mechanisms include:

1. Nervous system control

• The sympathetic system, mainly baroreceptors and chemoreceptors, promotes moderate vasoconstriction to maintain normal blood pressure.

• If this system responds inappropriately, it causes increased vasoconstriction, enhancing peripheral resistance and raising blood pressure.

2. Capillary fluid shifts

• Regulate blood volume by responding to arterial pressure.

• Increased pressure forces fluid into interstitial spaces; decreased pressure allows fluid to be drawn back into arteries by osmosis.

• This adjustment may take several hours.

3. Kidney excretion

• Regulates blood volume by modulating urine output.

• Normally, urine output is maintained at arterial pressure ~60 mm Hg.

• Below this pressure, urine formation ceases, increasing blood volume.

• Above this pressure, urine formation increases, decreasing blood volume.

• This also may take several hours.

4. Hormonal changes

• Activation of the kidney's renin-angiotensin-aldosterone system in response to low arterial pressure.

• This system causes vasoconstriction, increasing arterial pressure.

• Stimulates aldosterone release, which increases sodium retention, affecting blood volume.

Summary: Elevated blood pressure reflects breakdown or inappropriate response of these pressure-regulating mechanisms.

Signs and Symptoms

Elevated blood pressure primarily affects target organs and tissues. Common symptoms include:

History and physical examination

• If you detect sharply elevated blood pressure, quickly rule out life-threatening causes.

• After ruling these out, take a detailed history:

  • History of cardiovascular, cerebrovascular, diabetes, or renal disease.

  • Family history of hypertension, pheochromocytoma, polycystic kidney disease.

  • Onset of high blood pressure: abrupt or gradual?

  • Patient's age: sudden onset in middle-aged or elderly may suggest renovascular stenosis.

  • Essential hypertension may start in childhood but usually diagnosed near age 35.

  • Pheochromocytoma and primary aldosteronism commonly occur between ages 40 and 60.

  • Check for orthostatic hypotension: measure BP lying down, sitting, standing.

    • Normally, systolic BP falls and diastolic rises on standing.

    • Orthostatic hypotension: both pressures fall on standing.

Emergency Interventions: Managing elevated blood pressure

Hypertensive Crisis (BP > 180/110 mm Hg)

• Maintain patent airway in case of vomiting.

• Institute seizure precautions.

• Prepare to administer I.V. antihypertensives and diuretics.

• Insert indwelling urinary catheter to monitor urine output.

Less severe elevation

• Rule out life-threatening causes:

  • Pregnancy: suspect preeclampsia/eclampsia.

    • Bed rest, insert I.V. line.

    • Administer magnesium sulfate and antihypertensives.

    • Monitor vital signs closely.

    • If diastolic BP > 100 mm Hg despite therapy, prepare for induced labor or cesarean delivery.

    • Provide emotional support for premature delivery.

  • Hyperthyroidism: look for exophthalmos, enlarged thyroid, tachycardia, palpitations, widened pulse pressure, nervousness, fever > 37.8°C.

    • Prepare to administer antithyroid drugs.

  • Increased Intracranial Pressure (ICP): signs include decreased consciousness, fixed/dilated pupils, increased respiratory rate, bradycardia.

    • Maintain airway, institute seizure precautions, prepare I.V. diuretics, insert urinary catheter, monitor vitals every 15 minutes.

  • Dissecting Aortic Aneurysm: absent/weak peripheral pulses, chest pain.

    • Bed rest, prepare for surgery or antihypertensives.

  • Glomerulonephritis: symptoms like headache, palpitations, blurred vision, sweating, wine-colored urine, decreased urine output.

• Obtain detailed drug history (prescription, herbal, OTC).

• Assess medication compliance and patient's perception of hypertension.

• Explore psychosocial/environmental factors affecting BP control.

Physical examination details

• Use funduscope to check for intraocular hemorrhage, exudate, papilledema (severe hypertension signs).

• Cardiovascular assessment:

  • Check carotid bruits, jugular vein distention.

  • Skin color, temperature, turgor.

  • Palpate peripheral pulses.

  • Auscultate heart sounds for gallops, murmurs, abnormal rhythms.

  • Auscultate lungs for crackles, wheezing, abnormal breathing rates.

• Abdominal exam:

  • Palpate for tenderness, masses, liver enlargement.

  • Auscultate for abdominal bruits (renal artery stenosis).

  • Palpable enlarged kidneys and tender liver suggest polycystic kidney disease.

• Urine analysis for microscopic hematuria.

Medical causes of elevated blood pressure

Anemia

• Elevated systolic pressure with pulsations in capillary beds, bounding pulse, tachycardia, systolic ejection murmur, pale mucous membranes.

• Sickle cell anemia patients may show ventricular gallop and crackles.

Aortic Aneurysm (Dissecting)

• Sudden rise in systolic pressure initially, no diastolic change.

• Compensation fails → hypotension.

• Abdominal aneurysm symptoms: abdominal/back pain, weakness, sweating, tachycardia, dyspnea, pulsating abdominal mass, restlessness, confusion, cool clammy skin.

• Thoracic aneurysm symptoms: ripping chest pain radiating to neck/shoulders/back/abdomen, pallor, syncope, blindness, sweating, dyspnea, tachycardia, cyanosis, leg weakness, murmur, absent pulses.

Atherosclerosis

• Systolic pressure rises, diastolic normal or slightly elevated.

• Weak pulse, flushed skin, tachycardia, angina, claudication may be present.

Cushing’s syndrome

• More common in females.

• Elevated BP and widened pulse pressure.

• Truncal obesity, moon face, cushingoid signs.

• Usually caused by corticosteroid use.

Hypertension

• Essential hypertension develops insidiously, gradual increase over decades.

• Patient often asymptomatic except high BP.

• Rare complaints: suboccipital headache, lightheadedness, tinnitus, fatigue.

• Malignant hypertension: diastolic >120 mm Hg, systolic >200 mm Hg.

  • Pulmonary edema, jugular vein distention, dyspnea, tachypnea, tachycardia, coughing pink frothy sputum.

  • Severe headache, confusion, blurred vision, tinnitus, epistaxis, muscle twitching, chest pain, nausea, vomiting.

Increased intracranial pressure (ICP)

• Increased respiratory rate, then increased systolic pressure, widened pulse pressure.

• Bradycardia (Cushing’s reflex) occurs last.

• Symptoms: headache, projectile vomiting, decreased consciousness, papilledema, pupillary changes, hypertension.

Pheochromocytoma

• Rare tumor of adrenal medulla.

• Symptoms: sudden severe hypertension, tachycardia, sweating, headache, palpitations, tremors, abdominal pain, weight loss, dilated pupils.

• Hypertensive crises can be fatal without treatment.

Renal Disease

• Elevated BP caused by renal artery stenosis, chronic glomerulonephritis, polycystic kidney disease.

• Symptoms: hematuria, edema, proteinuria, azotemia.

• May have abdominal bruits, enlarged kidneys.

Thyrotoxicosis

• Widened pulse pressure, tachycardia, arrhythmia.

• Weight loss, heat intolerance, nervousness.

• Enlarged thyroid gland, exophthalmos.

Other Causes

• Obstructive sleep apnea, coarctation of the aorta, drugs (cocaine, NSAIDs), pregnancy-related hypertension.

Conclusion

Elevated blood pressure (hypertension) is a common but often unnoticed condition caused by various factors like kidney or hormonal disorders, requiring careful diagnosis to prevent life-threatening complications. Management includes identifying underlying causes, monitoring, and emergency interventions for hypertensive crises.