Hypertension – Study Notes

Hypertension – Study Notes

Types

• Essential (Primary) Hypertension

  • ~90% of cases.

  • Multifactorial, not a single identifiable cause.

  • Risk factors: advanced age, smoking, diabetes, obesity, high sodium diet, stress, genetics.

  • Pathophysiology:

    • Vessel wall thickening → narrowed lumen → ↑ systemic vascular resistance (SVR) → ↑ BP.

    • Excess sympathetic tone/vasoconstriction → ↑ SVR → ↑ BP.

    • Sodium retention → ↑ preload → ↑ stroke volume → ↑ cardiac output → ↑ BP.

• Secondary Hypertension (~10% of cases)

  • Consider when BP remains uncontrolled on ≥3 agents (“refractory hypertension”).

  • Causes:

    • Renal: Chronic kidney disease, renal artery stenosis → ↑ RAAS activation.

    • Endocrine:

      • Thyroid (hyperthyroidism → systolic HTN, hypothyroidism → diastolic HTN).

      • Hyperaldosteronism (↑ Na⁺/water retention).

      • Cushing’s syndrome/disease (↑ cortisol → ↑ sympathetic activity).

      • Pheochromocytoma (↑ catecholamines).

    • Neurological: ↑ Intracranial pressure (tumor, hemorrhage, edema) → Cushing’s triad (HTN, bradycardia, irregular respirations).

    • Aortic disease: Coarctation of aorta (↑ BP upper extremities, ↓ BP lower extremities, leg cyanosis).

    • Pregnancy-related: Preeclampsia (HTN, proteinuria, edema), Eclampsia (preeclampsia + seizures).

    • Substances: Cocaine, amphetamines, PCP, sympathomimetics.

    • Sleep apnea: Hypoxia → ↑ sympathetic tone → refractory HTN.

BP Classification

• Normal: <120/<80 mmHg

• Elevated (Pre-HTN): 120–129/<80

• Stage 1 HTN: 130–139 / 80–89

• Stage 2 HTN: ≥140 / ≥90

• Hypertensive Crisis: ≥180 systolic or ≥120 diastolic

  • Urgency: No target-organ damage.

  • Emergency: With target-organ damage.

Complications (Target Organ Damage)

1. Cardiovascular

   • LV hypertrophy → diastolic HF (HFpEF).

   • CAD, MI (due to atherosclerosis).

   • PAD (leg ischemia, pain, ulcers).

   • Aortic dissection (shearing forces).

   • Aortic aneurysm (esp. abdominal).

2. Neurological

   • Carotid stenosis → TIA.

   • Stroke (ischemic or hemorrhagic).

   • Intracerebral or subarachnoid hemorrhage.

3. Renal

   • Glomerulosclerosis (afferent arteriole thickening).

   • CKD or AKI.

   • Hematuria.

   • Hypertension + diabetes = leading CKD causes.

4. Retinal (Hypertensive Retinopathy)

   • Grade 1: AV nicking.

   • Grade 2: Constricted vessels.

   • Grade 3: Hemorrhages, cotton wool spots, microaneurysms.

   • Grade 4: Papilledema (hypertensive emergency red flag).

Diagnosis

• Measure BP in both arms.

• Confirm with ≥2 readings on separate visits.

• Rule out white coat HTN (ambulatory or home monitoring).

• Crisis: BP ≥180/120 → check for organ damage (emergency vs urgency).

Management

• Lifestyle Modifications (all patients):

  • DASH diet, ↓ sodium, ↓ alcohol, weight loss, regular exercise, smoking cessation.

• Stage 1:

  • If ASCVD risk <10% → lifestyle only.

  • If ASCVD risk ≥10% → lifestyle + medication.

• Stage 2:

  • Lifestyle + start medications immediately.

• First-line medications (essential HTN):

  • Thiazide diuretics.

  • ACE inhibitors or ARBs.

  • Calcium channel blockers (amlodipine, nifedipine).

• Special populations:

  • African-American: thiazides or CCBs preferred (low-renin hypertension).

  • Choice also depends on comorbidities (HF, CAD, CKD, diabetes).