IM

• Definition of hypertension:

  • Arbitrary; no obvious level of BP defines hypertension
  • In adults: continuous incremental risk of CVS, CNS, retinal disease across all levels of both SBP and DBP
  • Practical definition: BP value at which treatment benefits outweigh costs and hazards
• Hypertension is defined as the BP level at which treatment reduces BP-related morbidity and mortality, with CVS disease risk doubling for every 20 mmHg increase in SBP and 10 mmHg increase in DBP
• Classification of hypertension:

  • Primary hypertension (essential): cause is "unknown," responsible for 80-95%
  • Likely due to an interaction between genetic and environmental factors
  • Secondary hypertension: cause for elevated BP can be determined, secondary to a pre-existing disorder, accounts for 5-20%
• Factors implicated in essential hypertension:

  • All could be under genetic influence: renal dysfunction, peripheral resistance vessel tone, endothelial dysfunction, autonomic tone, insulin resistance, neurohumoral changes
• Environmental factors contributing to essential hypertension:

  • High salt intake, alcoholism, obesity, sedentary lifestyle, impaired intrauterine fetal growth
  • Little evidence that stress causes hypertension
• Endocrine disorders causing secondary hypertension:

  • Adrenal disorders like phaeochromocytoma, primary hyperaldosteronism, Cushing’s syndrome
  • Other endocrine disorders involve the thyroid gland, parathyroid gland, and anterior pituitary gland
• Drugs causing secondary hypertension:

  • Estrogen-containing oral contraceptives, corticosteroids, NSAIDs, cyclosporin, monoamine oxidase inhibitors, sympathomimetic agents, appetite suppressants
• Other causes of secondary hypertension:

  • Pregnancy, pre-eclampsia, coarctation of the aorta, alcohol, central obesity, familial dysautonomia, psychogenic factors
• Prevalence and epidemiology of hypertension:

  • Varies among countries and subpopulations
  • Present in all populations except very primitive cultures
  • Average SBP higher for men than women, DBP increases with age up to 55 years then tends to decrease
• Clinical features of hypertension:

  • Rarely accompanied by symptoms, identification usually through routine medical screening
  • Symptoms include headaches, lightheadedness, vertigo, tinnitus, altered vision, syncopes
• Diagnosis of hypertension:

  • Diagnosed based on persistently elevated resting blood pressure
  • Recommendations for multiple resting measurements over time for accurate diagnosis
• Treatment of hypertension:

  • Two approaches: non-pharmacological (lifestyle changes) and pharmacological (use of antihypertensives)
• Non-pharmacological treatment of hypertension:

  • Includes hygienic measures, dietary modifications like low sodium intake, increased potassium intake, moderation of alcohol consumption
• Lifestyle modifications to manage hypertension:

  • Dietary changes, physical exercise regimens like isometric resistance exercise, aerobic exercise, and device-guided breathing
• Investigations for hypertension:

  • Special investigations according to indication, including echocardiogram, renal ultrasound, renal angiography, urinary catecholamines, plasma renin activity
• Drug therapy is recommended for individuals with blood pressures >140/90 mmHg
• Lowering systolic blood pressure by 10–12 mmHg and diastolic blood pressure by 5–6 mmHg confers relative risk reductions of 35–40% for stroke and 12–16% for CHD within 5 years of the initiation of treatment
• Risk of heart failure is reduced by >50% with antihypertensive agents
• Major drug groups for hypertension treatment include Diuretics (frusemide, bendrofruazide), Beta-Blockers (propranolol, atenelol), ACE inhibitors (captopril, enarapril), Calcium channel blockers (verapamir, nifedipine), and Angiotensin receptor blockers (ARB’s) like lorsatan
• Principles of drug therapy for hypertension:

  • Initial use of low dose
  • If control is not achieved but drug is tolerable, increase dose of the same drug
  • For poor response & poor tolerance, change to another drug class
  • Prefer to add a small dose of another drug class rather than increase dosage of the same drug
  • Use appropriate drug combination to reach optimal BP (minimizes side effects of single drug)
  • Improve compliance by using long-acting sustained release preparations providing 24 hrs efficacy
• Causes of treatment failure in hypertension:

  • Nonadherence to Therapy
  • Inadequate patient education
  • Lack of involvement of the patients in the treatment plan
  • Adverse effects of medication
  • Pseudoresistance like "White-coat hypertension" or clinic elevations
  • Incorrect cuff size (use of regular cuff on large arm)
• Volume Overload can lead to treatment failure in hypertension due to excessive salt intake, renal insufficiency, Secondary Hypertension, Renovascular hypertension, Pheochromocytoma, and Primary aldosteronism
• Target organ damage in hypertension affects organs like BLOOD VESSELS, HEART, BRAIN, KIDNEYS, and EYES
• Blood vessels in hypertension:

  • In larger arteries (> 1 mm in diameter), the internal elastic lamina is thickened, smooth muscle is hypertrophied, and fibrous tissue is deposited leading to less compliant walls
  • In smaller arteries (< 1 mm), hyaline arteriosclerosis occurs, narrowing the lumen and potentially leading to aneurysms
  • Widespread atheroma may develop, increasing the risk of coronary and cerebrovascular disease
• Hypertensive retinopathy in hypertension can lead to changes in the optic fundi, "Cotton wool" exudates associated with retinal ischemia or infarction, and central retinal vein thrombosis
• Heart complications in hypertension include a higher incidence of coronary artery disease, left ventricular hypertrophy, atrial fibrillation, and potential left ventricular failure
• Kidney complications in hypertension can lead to proteinuria and progressive renal failure by damaging the renal vasculature
• Central nervous system complications in hypertension include stroke, cerebral hemorrhage or infarction, carotid atheroma, TIAs, subarachnoid hemorrhage, and hypertensive encephalopathy
• Hypertensive emergencies consist of acute blood pressure elevation associated with signs or symptoms of target organ damage like hypertensive encephalopathy, intracranial hemorrhage, unstable angina pectoris, acute myocardial infarction, acute left ventricular failure with pulmonary edema, dissecting aortic aneurysm, and eclampsia
• In hypertensive emergencies, the initial goal is to reduce blood pressure by no more than 25% within minutes to 1 or 2 hours, lowering BP to 160/100 mm Hg within 2–6 hours to avoid precipitating coronary, cerebral, or renal ischemia
• Treatment for hypertensive urgencies involves admitting the patient and offering oral antihypertensive with a relatively fast onset of action, typically using two complementary medications like a diuretic plus a beta-blocker or ACE inhibitor, and sometimes a calcium channel blocker