HYPERTENSION

Hypertension is an important medical and public health issue and leading causes of the global burden of disease. It is estimated that 1 billion people Worldwide are affected by hypertension. Raised blood pressure attributes to the leading risk factor for morbidity and mortality in India. Hypertension is attributable to 10.8% of all deaths in India. (ICMR 2018)

There is a direct relationship between hypertension and Cardiovascular disease (CVD)- Doubles the risk of cardiovascular diseases. Antihypertensive therapy clearly reduces the risks of cardiovascular and renal disease But large segments of the hypertensive population are either untreated or inadequately treated.

“Hypertension is defined as a systolic blood pressure greater than 140 mm Hg and a diastolic pressure greater than 90 mm Hg based on the average of two or more accurate blood pressure measurements taken during two or more contacts with a health care provider.”

(by JNC 7) The Seventh Report of  the Joint National Committee on Prevention, Detection,  Evaluation, and Treatment of High Blood Pressure

Classification of Blood Pressure

BP Classification	Systolic BP (mm Hg)	Diastolic BP (mm Hg)
Normal	<120	<80
Prehypertension	120–139	80–89
Stage 1 hypertension	140–159	90–99
Stage 2 hypertension	≥160	≥100

Classification of Hypertension

1. Primary (Essential) Hypertension : is high blood pressure that doesn't have a known cause. ( About 90% to 95% of all cases)
2. Secondary Hypertension : is high blood pressure that have a known specific cause. ( About 5% to 10% of all cases in adults)

Etiology

Contributing factors of Primary hypertension

1. Age
• > 55 for men; > 65 for women
2. Gender
• greater in women than men, but higher in men than women until after menopause.
3. Environmental factors
• Obesity
• Fat people have higher blood pressures than thin people.
• Sleep disordered breathing often seen with obesity may be an additional risk factor
• Alcohol intake
• close relationship between the consumption of alcohol and blood pressure level.
• But small amounts of alcohol seem to be beneficial
• Sodium intake
• Directly proportional
• some evidence that a high potassium diet can protect against the effects of a high sodium intake
• Stress
• Chronic stress – uncertain
• acute pain or stress can raise blood pressure
4. Genetic factors / Family history
• tends to run in families, by shared environmental influences.
• still largely unidentified genetic component.
5. Fetal factors
• Low birth weight: May be due to fetal adaptation to intrauterine undernutrition with
• long-term changes in blood vessel structure
• Or the function of crucial hormonal systems.
6. Ethnicity (African Americans)
• The African Americans have greater risks with an earlier onset of hypertension than Caucasians.
7. Sedentary lifestyle
• Sedentary lifestyles increase double the risk of having high blood pressure
8. Socioeconomic status
• Low SES is associated with higher blood pressure
9. Humoral mechanisms
• autonomic nervous system, renin angiotensin system, natriuretic peptide and kallikrein-kinin system - short-term changes in blood pressure
• But no convincing evidence - directly involved in the maintenance of hypertension
10. Insulin resistance - Metabolic syndrome
• hyperinsulinemia, glucose intolerance, reduced levels of HDL cholesterol, hypertriglyceridemia and central obesity with hypertension
• association between diabetes and hypertension has long been recognized

Secondary Hypertension

1. Renal disease
• Renal vascular disease
• Parenchymal renal disease, particularly glomerulonephritis
• Polycystic kidney disease
2. Endocrine disease
• Pheochromocytoma - vascular tumor of the adrenal gland
• Cushing’s syndrome – excessive cortisol
• Primary hyperaldosteronism (Conn’s syndrome)
• Hyperparathyroidism
• Primary hypothyroidism
• Thyrotoxicosis
• Liddle’s syndrome
3. Coarctation of the aorta
4. Pregnancy (pre-eclampsia)
5. Drugs
• Oral contraceptives containing oestrogens
• Anabolic steroids,
• Corticosteroids
• NSAIDs, carbenoxolone
• Sympathomimetic agents

Mechanisms of Hypertension

• Determinants of arterial pressure
• Cardiac output
• Stroke volume: related to myocardial contractility and to the size of the vascular compartment.
• Heart Rate: neuronal and hormonal control
• Peripheral resistance: functional and anatomic changes in small arteries and arterioles
• Intravascular Volume
• Sodium is predominantly an extracellular ion -primary determinant of the extracellular fluid volume
• When NaCl intake exceeds the capacity of the kidney to excrete sodium
• Vascular volume initially expands and cardiac output increases
• Autonomic Nervous System
• homeostasis via pressure, volume, and chemoreceptor signals
• Adrenergic reflexes - short term,
• Adrenergic function, in concert with hormonal and volume-related factors - long-term regulation
• three endogenous catecholamines are norepinephrine, epinephrine, and dopamine
• Renin-Angiotensin-Aldosterone
• Vasoconstrictor properties of angiotensin II
• Sodium-retaining properties of aldosterone
• Vascular radius
• Resistance to flow varies inversely with the fourth power of the radius,
• Compliance of resistance arteries
• High degree of elasticity: accommodate an increase of volume with relatively little change in pressure,
• Semi-rigid vascular system: small increment in volume induces a relatively large increment of pressure

Pathophysiology

• No precise cause can be identified for most cases of hypertension,
• Hypertension is a multifactorial condition. it is most likely to have many causes-
• there must be a change in one or more factors affecting peripheral resistance or cardiac output
• there must also be a problem with the body's control systems that monitor or regulate pressure.
• Single gene mutations have been identified for a few rare types of hypertension, but most types of high blood pressure are thought to be polygenic (mutations in more than one gene).
• Many factors have been implicated as causes of hypertension:
• Increased sympathetic nervous system activity related to dysfunction of the autonomic nervous system
• Increased renal reabsorption of sodium, chloride, and water related to a genetic variation in the pathways by which the kidneys handle sodium
• Increased activity of the renin-angiotensin-aldosterone system, resulting in expansion of extracellular fluid volume and increased systemic vascular resistance
• Decreased vasodilation of the arterioles related to dysfunction of the vascular endothelium
• Resistance to insulin action, which may be a common factor linking hypertension, type 2 diabetes mellitus, hypertriglyceridemia, obesity, and glucose intolerance
• Advance age related factors -
• Structural and functional changes in the heart and blood vessels
• These changes include –
• accumulation of atherosclerotic plaque,
• fragmentation of arterial elastin's,
• increased collagen deposits, and
• impaired vasodilation.
• The result of these changes is a decrease in the elasticity of the major blood vessels.

Clinical Manifestations

• Hypertension is often called the “Silent killer” because it is frequently asymptomatic- meaning “without symptoms” until it has become severe and damage to organs have occurred.
• A person with severe hypertension may have symptoms caused by the effects on the blood vessels which my be:
• Fatigue, Reduced activity tolerance
• Dizziness & Palpitations
• Angina (chest pain)
• And difficulty breathing

Complication

• Heart disease (left ventricular hypertrophy, angina or previous myocardial infarction, previous coronary revascularization, heart failure)
• Stroke (cerebrovascular accident, brain attack) or TIA
• Chronic kidney disease
• Peripheral arterial disease
• Retinopathy
• Malignant hypertension
• Also known as accelerated hypertension
• Blood pressure rises rapidly - diastolic blood pressure >120 mmHg
• Characterized by accelerated microvascular damage with necrosis in the walls of small arteries and arterioles (fibrinoid necrosis) and Intravascular thrombosis.
• Diagnosed by
• rapidly progressive end organ damage - retinopathy (grade 3 or 4)
• renal dysfunction (especially proteinuria)
• hypertensive encephalopathy
• Left ventricular failure may occur and, if this is untreated, death occurs within months

Assessment and Diagnostic Evaluation

• Health History and Physical Examination
• Diagnosis requires several elevated readings over several weeks (unless > 180/110)
• BP measurement in both arms -Use arm with higher reading for subsequent measurements
• Routine laboratory tests (All patients) include
• Urinalysis for blood, protein and glucose
• Blood urea, electrolytes and creatinine
• Blood glucose
• Serum total and HDL cholesterol
• 12-lead ECG - left ventricular hypertrophy, coronary artery disease
• Investigation: Selected patients
• Chest X-ray: cardiomegaly, heart failure, coarctation of the aorta
• Ambulatory BP recording: assess borderline or ‘white coat’ hypertension
• Echocardiogram: detect or quantify left ventricular hypertrophy
• Renal ultrasound: to detect possible renal disease
• Renal angiography: detect or confirm presence of renal artery stenosis
• Urinary catecholamines: possible pheochromocytoma
• Urinary cortisol and dexamethasone suppression test: possible Cushing’s syndrome
• Plasma renin activity and aldosterone: possible primary aldosteronism

Prevention of Hypertension

• Increase level of physical activity.
• Limit alcohol consumption to moderate levels
• Men - no more than 2 drinks per day and
• women - no more than one drink per day.
• 1 drink = 1.5 oz. alcohol or 12 0z. Beer, 5 oz. of wine, 1.5 oz 80 proof whiskey.
• Monitor Blood pressure and know if it is high, low, normal, or borderline for hypertension.
• Regular checkups with your Primary care Physician.

Medical Management

• The goal of management is -
• to deal with all the other identified risk factors for cardiovascular disease, including lipid disorders, glucose intolerance or diabetes, obesity, and smoking.
• to manage hypertension by achieving and maintaining the arterial blood pressure at 140/90 mm Hg or lower and 130/80 mm Hg for people with diabetes mellitus or proteinuria >1 g/24 hours.
• to prevent complications and death.
• Algorithm of hypertension treatment

Lifestyle Modifications

• Increase level of physical activity- Engage in regular aerobic physical activity such as brisk walking (at least 30 minutes per day, most days of the week).
• Limit alcohol consumption to moderate levels
• Men - no more than 2 drinks per day and
• women - no more than one drink per day.
• 1 drink = 1.5 oz. alcohol or 12 0z. Beer, 5 oz. of wine, 1.5 oz 80 proof whiskey.
• Monitor Blood pressure and know if it is high, low, normal, or borderline for hypertension.
• Regular checkups with your Primary care Physician.

Drug Therapy

• Diuretics
• Thiazide-type Diuretics
• Inhibit NaCl reabsorption
• Side effects:
• Electrolyte imbalances: ↓ Na, ↓ Cl, ↓ K** (advise K rich foods)
• Fluid volume depletion (monitor for orthostatic hypotension)
• Impotence, decreased libido
• Calcium Channel Blockers(CCB)
• Block movement of calcium into cells, causing vasodilation
• Side effects - Brdaycardia, heart block
• Angiotensin-Converting Enzyme Inhibitors (ACE-I)
• Enalapril, captopril
• Prevents conversion of angiotensin I to angiotensin II, thereby preventing the vasoconstriction associate with A II.
• Side effects -Hypotension, cough
• Angiotensin II Receptor Blockers (ARBs)
• help relax your blood vessels, which lowers your blood pressure and makes it easier for your heart to pump blood.
• Side effects – Hypotension (Varied, depending on specific drug)
• Beta Blockers (BB) (metoprolol, propranolol)
• Block β – adrenergic receptors (↓ HR, ↓ inotropy, reduces sympathetic vasoconstriction)
• Side effects - Bradycardia, hypotension, heart failure, impotence

Nursing Management

• Nursing Diagnosis
1. Noncompliance with medication regimen and lifestyle changes.
2. Readiness for Enhanced Self-health Management related to control of hypertension and prevention of target organ disease.

1.Enlisting Cooperation and Compliance

• Assess the patient’s cooperation level in redirecting lifestyle modification, acknowledge the difficulty, and provide support and encouragement.
• Develop a plan of instruction for medication self-management. Plan the patient’s medication schedule so that they are taken at proper and convenient times (once daily, if possible)
• Assess for and try to eliminate side effects of medication regimen.
• Explain that antihypertensive drugs affect people differently, and side effects such as anorexia, fatigue, nausea, or light-headedness often occur during the first few days or weeks of therapy until the body develops tolerance to them.
• Warn the patient of the possibility that orthostatic hypotension may occur initially with some drug therapy, but it can be minimized by being cautious in hot, humid environments; getting up slowly; or sitting or lying down briefly if feeling faint.
• If constipation occurs, encourage high-fiber diet.
• If ankle swelling occurs, elevate legs periodically.
• If dry cough develops, dosage or drug may need to be changed.
• Older patients are also more sensitive to therapeutic levels of drugs and may demonstrate adverse effects while on an otherwise average dosage. Monitor closely for safety and efficacy of therapy.
• Advise the patient to notify the health care provider if side effects are significant, dosage may be lowered or a substitute medication may be ordered. However, the patient should not discontinue medication without notifying the health care provider.
• Educate the patient to be aware of serious adverse effects (fainting, palpitations, shortness of breath) and report them immediately so that adjustments can be made in individual pharmacotherapy.

2.Encouraging Self-Management

• Explain the meaning of high BP, risk factors, and their influences on the cardiovascular, cerebral, and renal systems.
• Stress that there can never be total cure, only control, of essential hypertension; emphasize the consequences of uncontrolled hypertension.
• Instruct the patient regarding proper method of taking BP at home and at work if health care provider so desires. Inform patient of desired range and the readings that are to be reported.
• Determine recommended dietary plans and provide dietary education
• suggest food preferences that include whole grains, fruits, vegetables, low-fat dairy, and nuts.
• Teach patient and family members how to read food labels in order to monitor sodium intake.
• Educate patient about factors that may affect BP, such as dehydration, diarrhea, and other illnesses, so BP should be monitored closely and treatment adjusted.
• Encourage the patient to keep follow-up as directed by health care provider and schedule eye exam by an ophthalmologist yearly.