Evaluation and treatment of hypertension

Essentials of Diagnosis

• Diastolic pressure greater than 90 mm Hg, systolic pressure greater than 140 mm Hg, or both, on three separate occasions
• In diabetic patients, diastolic pressure greater than 80 mm Hg, systolic pressure greater than 130 mm Hg, or both, on three separate occasions

Treatment

• A growing body of direct and inferential evidence suggests that reduction of blood pressure should not be the only goal of antihypertensive therapy. Therapy should also be directed toward controlling all of the patients' cardiovascular risk factors, including dyslipidemia, smoking, and diabetes mellitus.
• The goal of treating high blood pressure is to reduce blood pressure and thereby prevent or reverse end-organ damage without causing significant side effects or requiring unacceptable changes in lifestyle. We now have many classes of antihypertensive agents that effectively lower blood pressure, either alone or in conjunction with an agent from another class of drugs. Because of the potentially detrimental metabolic changes caused by some agents, their failure to reduce the incidence of myocardial infarction, and the multisystem involvement of hypertension, it is essential to choose a regimen that effectively lowers blood pressure without causing abnormalities. The following recommendations incorporate data from large long-term trials and experimental evidence from human and animal studies.
• Nonpharmacologic therapy and coronary risk factor reduction should be initiated in all patients once the diagnosis of sustained hypertension is made. Individuals with mild (systolic BP, 140–159; diastolic, 90–99) or moderate (systolic, 160–179; diastolic, 100–109) hypertension can be treated with nonpharmacologic therapy for 3–6 months. If this fails to reduce blood pressure to below 140/90 mm Hg within that time, pharmacologic therapy should be initiated. If end-organ damage is already present at diagnosis, or if other major coronary risk factors such as diabetes or dyslipidemia are present, pharmacologic therapy should be initiated once the diagnosis has been made. Individuals with severe hypertension (systolic BP higher than 180; diastolic higher than 110) should have both nonpharmacologic and drug therapy initiated once the diagnosis is made.

Nonpharmacologic Therapy

• Nonpharmacologic therapy should be encouraged in all hypertensive patients. The approaches of proven benefit are weight reduction in obese patients, moderate aerobic exercise in sedentary patients, a reduction in alcohol consumption in all patients who drink, and a reduction of salt intake in some patients.

• Obesity

• Obesity (more than 10% over ideal weight) is associated with hypertension, diabetes, hyperlipidemia, and excess coronary mortality. In obese patients, a decrease of as much as 2 mm Hg of diastolic blood pressure can be achieved for every 3 lb of weight loss. The benefits of weight reduction start early in the course, with a loss of as little as 10–15 lb. Although all obese patients should be encouraged to lose weight, the process is usually difficult and frequently requires extensive support and sometimes a financial investment. The use of all "stimulant" type weight reduction therapies should be strictly avoided, as they tend to elevate blood pressure. The fat substitutes or avoidance therapies do not raise blood pressure but have their own side effects.

• Exercise

• Regular exercise in a previously sedentary individual may reduce diastolic blood pressure as much as 10 mm Hg. The level of exercise should be that required to raise the heart rate to 50–60% of the maximal predicted heart rate. Walking briskly for 45 min three to five times per week should suffice for most previously sedentary individuals. Increasing the amount of exercise in a previously active individual, however, seldom decreases blood pressure.

• Alcohol Consumption

• Alcohol consumption causes acute increases in blood pressure and can cause sustained hypertension in a significant proportion of patients. Hypertensive patients should be encouraged to limit their alcohol consumption to 1 oz of ethanol per day, the equivalent of 2 oz of 100-proof hard liquor, 8 oz of wine, or 24 oz of beer. Even this level of alcohol consumption is associated with increased overall mortality. Alcohol decreases cardiovascular mortality and appears to decrease the onset of diabetes by improving insulin resistance. The best data for these benefits are for wine. Beer with its even higher carbohydrate load should be avoided in diabetics.

• Cigarette Smoking

• Smoking cigarettes can greatly increase your risk for developing heart disease. Smoking can raise your blood pressure. Smoking narrows your blood vessels and speeds up the process of atherosclerosis. Atherosclerosis is a condition where plaque buildup causes narrowing and hardening of major arteries.

• Sodium Reduction

• Reducing sodium in the diet has been shown to reduce blood pressure in most people to a modest degree. Hypertensive patients, older individuals, and blacks tend to be more salt-sensitive, and achieve larger reductions in blood pressure with salt restriction. Hypertensive patients should be encouraged to keep sodium chloride consumption to less than 4–6 g/d.

• Stress

• Stress has long been known to raise blood pressure acutely and has been implicated in the genesis of sustained hypertension, even though no clear relationship has been demonstrated. Reducing stress would seem to be a reasonable form of non-pharmacologic therapy, but no controlled studies have demonstrated significant improvement in blood pressure with stress avoidance or relaxation therapy.

Pharmacologic Therapy:

• Drug Groups and Medications

• As a rule we will start with one drug ,so combination of drugs comes later on , but not immediately, and you should choose a drug to start with it is very important because we have varieties of drugs Thiazides is on top of the List, The Aim as already mentioned to prevent irreversible damage to retina, kidneys, and heart failure and the treatment if the diagnosis establish is an all life Treatment

• How drugs can lower blood pressure

• Drugs which lower the total peripheral vascular resistance by either:

1. Sympathetic blocking agents.
2. Vasodilators.
3. Angiotensin - converting enzyme (ACE) inhibitors.
4. Calcium channel blockers.
5. Nitrates.

• Drugs which lower the cardiac output- Beta blockers.
• Drugs which decrease blood volume - Diuretics.
• Drugs which act Centrally (CNS) by decrease the secretion of epinephrine and dopamine.

DIURETICS:

• Drugs or any substances which increases the urine flow.
• Body produces 180L of glomerular filtrate each day.
• Only 1.5L of urine is excreted.
• ascending loop of henle which is the major site of salt reabsorption (30% of Nacl is reabsorbed) Where High efficacy Diuretics act (ie.Furosemide)
• distal convoluted tubule: 10% of Na is reabsorbed (thiazides)

• Loop diuretics or HIGH EFFICACY loop diuretics:

• Furosemide ( the trademark is lasix)
• It is the most diuretic used in the emergency (ICU or CCU).
• The major action is on the thick ascending loop of henle.
• They decrease K, Na, Cl reabsorption. This is very important.
• Patient with kidney shutdown give him IV furosemide ( 80mg ) after (0.5 -1) hour the patient will produce urine for example (300- 400)ml of urine
• They are very effective, very potent.
• They increase Ca⁺², Mg excretion.
• The onset is very rapid 30 minutes after oral and 5 minutes after IV.
• Indications:

• Acute Pulmonary oedema.
• Acute hypercalcaemia.
• Hyperkalemia.
• Acute renal failure.
• Toxic manifestations of poisoning.
• First line therapy in acute medical emergencies.

• Toxicity

• Hypokalemia
• ototoxicity, especially if given with aminoglycosides
• Hyperuricaemia (compete with uric acid for excretion).

• Thiazides diuretics

• They are Hydrochlorthiazide , Chlorothiazide , Bendrofluazide, Chlorthalidone
• the first line therapy: mild hypertension : either thiazide diuretics (one drug) or β- blocker or combination
• They inhibit the reabsorption of sodium and chloride in the distal convoluted tubules.
• So very important that means they cause loss of K again.
• They increase the absorption of Ca⁺², so it causes hypercalcaemia.
• First these thiazides reduce the blood volume but when long term use (more than 6 weeks) they have another effect, so they reduce PVR.
• Indications

• Hypertension.
• Congestive cardiac failure (CCF).
• Renal stone due to hypercalciuria (decrease calcium concentration in urine).
• Nephrogenic diabetes insipidus .

• They should be given with K- sparing diuretics because of hypokalemia.
• Very important to remember the toxicity :

• HYPOKALAEMIA - 70% (Hypokalemic metabolic alkalosis).
• Hyperuricemia - 70%.
• Hyperglycemia -10%.
• Hypercalcemia.
• Hyperlipidemia (raised cholesterol and LDL).