Hypertension

Hypertension Basics

  • Definition: High blood pressure (BP) characterized by consistent readings >140 mmHg systolic and >90 mmHg diastolic.

  • Normal BP reading: 120/80 mmHg (systolic/diastolic).

Importance of Measuring BP

  • BP is vital for organ function and waste removal; an absence can lead to shock or death.

  • Proper Measurement: Requires avoiding food, caffeine, tobacco, and alcohol 30 mins beforehand; sitting calmly for 5 mins; correct arm positioning and cuff size.

    • Take repeat reading 1-3 minutes after first reading

    • Too small cuff size → may measure too high; too large cuff size → may measure too low

    • Cuff higher than heart → reading may be too low; cuff lower than heart → reading may be too high

  • Check the patient’s HR as well (e.g. slow HR + high BP = possible concern)

Prevalence

  • Affects approximately 1.28 billion adults; common in low/middle-income countries.

Types of Hypertension

  • Primary (Essential) Hypertension:

    • Most common type (accounts for 90-95% of cases).

    • Chronic condition not linked to/caused by an underlying condition

    • Often linked to lifestyle factors (diet, activity, stress) and genetic predisposition.

  • Secondary Hypertension:

    • Caused by an underlying, identifiable condition.

    • Tends to appear suddenly and cause higher BP than primary hypertension.

    • Causes include:

      • Kidney disease

      • Pheochromocytoma: adrenal gland tumors

      • Thyroid dysfunction

      • Obstructive sleep apnea

      • Certain medications (e.g. stimulants, some NE based antidepressants, decongestants (causes vasoconstriction → higher BP), NSAIDS).

  • Malignant Hypertension:

    • Hypertensive crisis (SBP >= 180 mmHg or DBP >= 120 mmHg)

    • Sudden increase in BP in people who already have high BP

    • May cause stroke, kidney failure, other end organ damage

    • Due to poor control of hypertension (e.g. non-adherence to medication, unknown HTN)

    • Requires rapid reduction of BP to ~160 mmHg to prevent tissue damage

      • Lowering beyond 160 too quickly can cause hypotension symptoms

Stages of Hypertension

  1. Normal: SBP < 120 and DBP < 80

  2. Elevated: SBP 120-129 and DBP < 80

  3. Stage 1 Hypertension: SBP 130-139 or DBP 80-89

  4. Stage 2 Hypertension: SBP >= 140 or DBP >= 90

  5. Hypertensive Crisis: SBP > 180 or DBP > 120

Symptoms of Hypertension

  • Most patients do not show any symptoms of hypertension

  • If the patient’s BP is > 180120 they may experience:

    • Severe headaches

    • Chest pain (a sign that the patient may experience a cardiovascular event soon)

    • Dizziness

    • Difficulty breathing, nausea, vomiting

    • Blurred vision/other vision changes

    • Anxiety (may be heading towards MI), confusion (may be heading towards stroke), tinnitus

    • Nosebleeds (i.e. burst vessels in the nose because of high BP)

    • arrhythmia

Complications of Hypertension

  • Inflammation and death of arterioles

  • Narrowing of blood vessels; arteriosclerosis

  • Restriction of blood flow to organs (kidney, brain, eye) → tissue damage

  • Left ventricle enlargement, which can trigger/exacerbate heart failure, angina

  • Sexual dysfunction

  • Cognitive impairment

  • Pulmonary edema

Risk Factors

  • Modifiable: Unhealthy diet, physical inactivity, tobacco/alcohol use, obesity, stress.

  • Non-modifiable: Age (>65), genetic predisposition, certain races (higher risk in Black, Hispanic, Asian adults).

Goals of Therapy

  • Promote lifestyle changes (reduce stress, healthy diet, exercise).

  • Target BP readings (if they have high BP, we want to get down to these levels): Home <135/85 mmHg, Office <140/90 mmHg.

    • Isolated systolic hypertension target: < 140 mmHg (150 mmHg if >= 80 years old)

    • Diabetes mellitus target: < 130/80 mmHg

Non-Pharmacological Treatments

  • Dietary recommendations: Reduce sodium intake, DASH diet, weight loss, and regular physical activity (150 mins/week).

    • 19-50 years old: 1500 mg/day sodium intake

    • 51-70 years old: 1300 mg/day sodium intake

    • >= 71 years old: 1200 mg/day sodium intake

Pharmacological Treatments

  • Common Classes:

    • ACE Inhibitors (ACEI): Block angiotensin conversion from AT I to AT II; first-line therapy (e.g., Lisinopril, Enalapril).

      • AT II is a potent vasoconstrictor and promotes aldosterone and norepinephrine release

      • Drug of choice for secondary hypertension caused by chronic kidney disease, diabetes, CAD, recent MI, and heart failure

      • not recommended as first-line therapy for African-American patients

      • Very rarely causes dry cough, hyperkalemia, angioedema

    • ARBs (-sartan): Block AT II receptors (e.g., Losartan, Valsartan).

      • First-line therapy if patient cannot tolerate ACE Inhibitors

    • Beta Blockers: Control heart rate (e.g., Metoprolol); given for younger patients (< 60 years old), stable angina, heart failure (start low and titrate slowly), history of MI, migraines, tachycardia, essential tremor

      • Block the release of adrenaline and noradrenaline in certain parts of the body

      • First-generation: Nonselective antagonists of beta-1 (heart) and beta-2 (lungs) receptors

      • Second-generation: Dose dependent beta-1 receptor antagonists

      • Third-generation: beta-1 receptor antagonists and vasodilators

      • Can cause slow HR, cold hands and feet, sleep disturbances, nausea/vomiting, sexual dysfunction, blurred vision, dry mouth/eyes

      • Contraindicated in patients with acute/chronic bradycardia and/or hypotension. Nonselective beta blockers should not be used in patients with asthma (cardio-selective may be allowed)

      • Avoid stopping abruptly, as this can cause arrhythmia or angina

    • Calcium Channel Blockers (CCB): Lower blood pressure by preventing calcium from entering cells of the heart and blood vessels (vasodilator) (e.g., Amlodipine, Verapamil).

      • Non-dihydropyridines: slow HR and cause vasodilation

      • Dihydropyridines: mainly cause peripheral vasodilation

      • Long acting dihydropyridine (DHP) CCBs can be used as first line; short-acting may increase risk of cardiovascular events

      • Effective in elderly patients with isolated systolic hypertension and African-American patients

      • Can cause dizziness, headaches, nausea, flushed skin, ankle edema, constipation, angina, palpitations, symptoms of MI, increased symptoms of GERD or heartburn

      • Contraindicated in patients with hypersensitivity or severe hypotension. Caution/avoid in patients with renal/hepatic impairment, pregnancy, low blood sugar, Parkinson’s, or depression.

    • Diuretics: Increase urine output to lower BP (e.g., Hydrochlorothiazide).

      • Also drug of choice for secondary hypertension caused by kidney disease

      • Thiazide diuretics: promotes elimination of water and electrolytes. Acts on distal tubule. Decreases vasoconstriction at arterioles, peripheral resistance, and blood volume; stimulates aldosterone secretion leading to increased potassium elimination

        • Can cause dehydration and low electrolytes, increased urination, hypercalcemia, hyperuricemia, hyperglycemia and glucose intolerance, impotence, photosensitivity

      • Loop diuretics: Acts on ascending loop of Henle. MOST potent diuretics.

        • Mainly reserved for patients with impaired renal function

      • Aldosterone Receptor Antagonists (Spironolactone): about as effective as potassium sparing diuretics; usually used in heart failure, liver disease, and hypokalemia

        • Also used to treat acne in some patients

    • Alpha Antagonists: Lower BP by blocking alpha receptors (causes vasodilation); main side effect is postural hypotension (start low, go slow)

      • Do not stop abruptly, may cause rebound hypertension

    • Other Agents: Clonidine (alpha antagonist effect; decreases vasoconstriction), methyldopa (alpha antagonist effect; can be used in pregnancy or patients with renal insufficiency).