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CHAPTER 9
C H A P T E R 9 HYPERTENSION IN General Considerations · Blood pressure changes during pregnancy: - Perinatal and fetal mortality increase when diastolic pressure exceeds 90 mmHg. - Blood pressure decreases early in pregnancy to reach its lowest level at 16-28 weeks with a drop in systolic pressure of 9 mmHg and diastolic pressure of 17 mmHg. - Upper limit of normal diastolic pressure: In second trimester 75 mmHg. In third trimester 85 mmHg. · Blood pressure should be measured in the sitting or in the lateral recumbent position. Phase IV Korotkoff’s sounds is used to define diastolic pressure. · Hypertension complicates 8-10% of all pregnancies. HYPERTENSION DISORDERS IN PREGNANCY 1. Pre-eclampsia — Eclampsia Pre-eclampsia 1. Hypertension 2. Hypertension in Special Groups
3. Generalized Edema 4. Sometimes blood coagulation defects and liver dysfunction. Incidence: 5-10% of all pregnancies primarily in primigravida after 20th week. Eclampsia Manifestations of eclampsia plus convulsions. 2. Chronic Hypertension of Whatever Cause · Presence of hypertension prior to or following pregnancy. · Blood pressure levels of ³ ð140/85 mmHg prior to the 20th week of pregnancy. · Benign course in the majority with blood pressure falling into normal range during second trimester. Failure of blood pressure to decrease predicts a complicated course. 3. Chronic Hypertension with Superimposed Preeclampsia · High incidence of maternal complications. Increase in systolic pressure of 30 mmHg or more and diastolic pressure of 15 mmHg or more with proteinuria and generalized edema. 4. Late or Transient Hypertension · Recurrent hypertension during subsequent pregnancies predict the development of chronic hypertension later in life. · Hypertension alone during late months of pregnancy or in the early Hypertension in Special Groups purperium. · Return to normal blood pressure within 10 days after delivery. Management · Individualize Therpay: Acute vs Chronic Cases - In acute cases, start drug therapy when diastolic pressure is < 105 mmHg and lower blood pressure gradually to levels between 90-100 mmHg. - In chronic hypertensive patients, start drugs at diastolic pressure > 95 mmHg. Start at lower levels of diatsolic pressure if there is renal disease or diabetes. - In pre-eclampsia patient should be hospitalized. - Indications of delivery: 1. Impending eclampsia. 2. Diastolic pressure > 110 mmHg after 24 hour hospitalization. 3. Rising serum creatinine. 4. Abnormal liver functions. Drugs for Acute Hypertension 1. Hydralizine: 5 mg i. v. repeated every 20 to 40 minutes or constant infusion 0.5-10 mg/hour. 2. Nifedipine: 10 mg orally repeated in 30 minutes if necessary, then 10-20 mg/3-6 h. 3. Diazoxide: 30-50 mg i.v. every 5-15 minutes. 4. Labetalol: 20 mg i.v. then 20-80 mg/20-30 minutes. Drugs for Chronic Hypertension 1. Methyldopa: 500-3000 mg/day in 2-4 divided doses. 2. Beta-Blockers: Used when blood pressure is not adequately controlled with methyldopa. 3. Hypertension in Special Groups
HYPERTENSION IN THE ELDERLY General Considerations · Hypertension and its complications are relatively common in the elderly. More than 60% of individuals above the age of 65 years have hypertension ( >140/90 mmHg ). · Isolated systolic hypertension is more common in old age; present in 68% of individuals above the age of 65 years. · Hypertension is dangerous in elderly individulas and is the major risk factor for stroke, heart failure and heart attacks. · Risk of hypertension increases with rising levels of both systolic and diastolic pressures. · Systolic blood pressure increases the risk of stroke, left ventricular hypertrophy and congestive heart failure more than the diastolic pressure. · Hypertension should be treated in the elderly patients. Rise in blood pressure is not a normal part of the aging process. · Elderly individuals have less efficient renal and hepatic functions, so drug dosage must be carefully monitored. · There is a high incidence of other concomitant diseases, e.g., diabetes mellitis, arthritis, heart disease which may complicate therapy. Causes of Increased Prevalence of Hypertension in the Elderly 1. Vascular Changes - Increase in rigidity and decrease in elasticity of the aorta and large vessels with aging which leads to increase in systolic blood pressure and pulse pressure. - Hyaline degeneration in the media of arterioles with decrease in lumen to wall ratio, narrowing of blood vessels and increase in Hypertension in Special Groups peripheral resistance. 2. Baroreceptor Sensitivity - Normally rise in blood pressure is attenuated by baroreceptor reflexes which causes peripheral vasodilation and cardiac slowing. - In aging there is a decrease in baroreceptor sensitivity with increased susceptibility to fluctuations in blood pressure and orthostatic hypotension. 3. Obesity - Increase in body fat is common with aging. - Increase in body mass index is associated with rise in blood pressure. 4. Renal Changes - Decline in glomerular filtration rate with aging, decrease in number of functioning glomeruli. - More time is needed to secrete a sodium chloride load. - Decreased ability to concentrate or dilute urine. 5. Increased Salt Consumption - Secondry to diminished taste sensitivity with aging. 6. Physical Inactivity - Increase in blood pressure due to deconditioning and sedentary life style. 7. Sleep Disorders - More common in the elderly. 8. Other Causes of Secondary Hypertension - Alcohol. - Drugs: Nonsteroidal anti-inflammatory drugs (NSAIDS) commonly Hypertension in Special Groups used because of the prevalence of degenerative arthritis in elderly. - Atherosclerotic renal artery stenosis leading to renovascular hypertension. - Chronic renal parenchymal disease due to prostatic obstruction, a low-grade chronic glomerulonephritis or pyelonephritis. CLINICAL CHARACTERISTICS OF HYPERTENSION IN THE ELDERLY 1. Pseudohypertension — Errors in Diagnosis - Falsely high sphygmomanometer readings as a result of increased arterial rigidity caused by medial sclerosis. - Suspect pseudohypertension: 1. Target organ damage is absent despite high blood pressure readings. 2. Symptoms of hypotension while sphygmomanometer pressure is high. 3. Arterial wall is felt while inflating sphygmomanometer cuff above systolic pressure and absence of arterial pulsations (Osler maeuver). 2. Postural Hypotension - Common in the elderly because of baroreceptor dysfunction. - 18% of untreated elderly hypertensives will have a decrease of systolic blood pressure of 20 mmHg or more after 1-3 minutes in the standing position. 3. Blood Pressure Variability - Excessive lability and fluctuations in blood pressure are common in the elderly ecause of: 1. Decrease in baroreceptor sensitivity.
2. Hypertension in Special Groups Increased blood pressure sensitivity to food intake; post-prandial hypotension. 3. Drug intake, e. g., NSAIDS. Obtain six to nine blood pressure measurements on 2-3 occasions to establish the diagnosis and categorization of hypertension. 4. Silent Auscultatory Gap - When measuring blood pressure there is a silent period while ausculating Korotkoff’s sounds (see chapter 3 on blood pressure measurement). 5. Target Organ Damage is More Common in the Elderly - Advanced optic fundus hypertensive changes. - Signs of left ventricular hypertrophy and ischemic heart disease. - Abdominal aortic aneurysm. - Vascular bruits, decreased carotid and peripheral pulsations. - Signs of heart failure. - Proteinuria, elevated serum creatinine. 6. Associated and concomitant diseases are more prevalent in elderly hypertensives than young hypertensives. Treatment of Hypertension in the Elderly Goals of Treatment 1. Hypertension in Special Groups For diastolic hypertension, reduce diastolic pressure to below 90 mmHg (same as young hypertensives). 2. For systolic hypertension, reduce systolic pressure to below 160 mmHg. Lifestyle modification should be tried first: Weight reduction, salt and alcohol restriction. Drug Treatment Guidelines 1. Start with smaller doses, at almost half the standard of younger adult dose. 2. Increase the dose far more gradually – over several weeks. 3. Check blood pressure always in supine and standing positions. Titrate doses according to standing pressures to avoid excessive orthostatic hypotension. 4. Avoid drugs prone to cause orthostatic hypotension especially central sympatholytes which may cause depression, confusion and pseudo-dementia. 5. Monitor renal function and electrolyte status in patients on diuretics or ACE inhibitors. 6. Adverse drug reactions are two to three times more common in the elderly. 7. Follow-up visits should be scheduled every two to four weeks until blood pressure is controlled. 8. Diuretics are the preferred initial drugs unless there is a special reason to use another agent. HYPERTENSION IN CHILDREN AND ADOLESCENTS General Considerations · Blood pressure is lower in children than in adults but increases gradually throughout the first and second decades of life. · Diagnosis of hypertension in children is made at levels of blood pressure considerably lower than in adults. · Hypertension in Special Groups When hypertension at a level high enough to require antihypertensive therapy in children, it is usually secondary in nature. Blood Pressure Measurement 1. Appropriate blood pressure cuff size is critical for accurate blood pressure measurement. 2. Diastolic blood pressure is defined as the Fourth Koretkoff’s phase. Definitions · Normal: Systolic or diastolic blood pressures less than the 90th percentile for sex and age. · High Normal: Average systolic and/or diastolic blood pressures between the 90th and 95th percentiles for age and sex. · Hypertension: Average systolic and/or diastolic blood pressures equal to greater than the 95th percentile for age and sex, with measurements obtained on at least three occasions. Classification 1. Significant Hypertension: Blood pressure between the 90th and 99th percentiles of distribution. 2. Severe Hypertension: Blood pressure at the 99th percentile or above. Prevalence Blood pressure of 140/90 mmHg or greater is present in less than 1% of children between 5 and 18 years.
Classification of Hypertension by Age Group* Age Group
* Report of the Second Task Force on Blood Pressure Control in Children 1987. Causes of Hypertension in Children and Adolescents 1. Renal parenchymal disease. 2. Coarctation of the aorta. 3. Renal artery stenosis. 4. Hypercalcemia. 5. Neurofibromatosis. 6. Neurogenic tumours. 7. Pheochromocytoma. 8. Mineralocorticoid excess. 9. Sleep apnea. 10. Essential hypertension. Diagnostic Evaluation of the Hypertensive Child 1. Complete blood count. 2. Serum electrolytes, creatinine, urea, calcium, uric acid,cholesterol. 3. Urine analysis, urine culture. 4. Renal ultrasound. 5. lostopic renogram. 6. Echocardiogram. 7. Urine collection for catecholamines. 8. Plasma and urinary steroids. Hypertension in Special Groups 9. Renal arteriography. Treatment of Essential Hypertension in Children 1. Nonpharmacologic: Weight reduction, exercise, diet adjustment. 2. Drugs: Same as in adults.
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