Hypertension is the most common cardiovascular disease. The prevalence of hypertension increases with advancing age; for example, about 50% of people between the ages of 60 and 69 years old have hypertension, and the prevalence is further increased beyond age 70. Elevated arterial pressure causes pathological changes in the vasculature and hypertrophy of the left ventricle. As a consequence, hypertension is the principal cause of stroke, is a major risk factor for coronary artery disease and its attendant complications myocardial infarction and sudden cardiac death, and is a major contributor to cardiac failure, renal insufficiency, and dissecting aneurysm of the aorta.
Hypertension is defined conventionally as a sustained increase in blood pressure ³140/90 mm Hg, a criterion that characterizes a group of patients whose risk of hypertension-related cardiovascular disease is high enough to merit medical attention. Actually, the risk of both fatal and nonfatal cardiovascular disease in adults is lowest with systolic blood pressures of less than 120 mm Hg and diastolic BP less than 80 mm Hg; these risks increase progressively with higher systolic and diastolic blood pressures. Recognition of this continuously increasing risk provides a simple definition of hypertension. Although many of the clinical trials classify the severity of hypertension by diastolic pressure, progressive elevations of systolic pressure are similarly predictive of adverse cardiovascular events; at every level of diastolic pressure, risks are greater with higher levels of systolic blood pressure. Indeed, beyond age 50 years, systolic blood pressure predicts outcome better than diastolic blood pressure. Systolic blood pressure tends to rise disproportionately greater in the elderly due to decreased compliance in blood vessels associated with aging and atherosclerosis. Isolated systolic hypertension (sometimes defined as systolic BP >140 to 160 mm Hg with diastolic BP 60 years of age.
At very high blood pressures (systolic ³210 and/or diastolic ³120 mm Hg), a subset of patients develops fulminant arteriopathy characterized by endothelial injury and a marked proliferation of cells in the intima, leading to intimal thickening and ultimately to arteriolar occlusion. This is the pathological basis of the syndrome of immediately life-threatening hypertension, which is associated with rapidly progressive microvascular occlusive disease in the kidney (with renal failure), brain (hypertensive encephalopathy), congestive heart failure, and pulmonary edema. These patients typically require in-hospital management on an emergency basis for prompt lowering of blood pressure. Interestingly, isolated retinal changes with papilledema in an otherwise asymptomatic patient with very high blood pressure (formerly called “malignant hypertension”) may benefit from a more gradual lowering of blood pressure over days rather than hours.
The presence of pathologic changes in certain target organs heralds a worse prognosis than the same level of blood pressure in a patient lacking these findings. Thus, retinal hemorrhages, exudates, and papilledema indicate a far worse short-term prognosis for a given level of blood pressure. Left ventricular hypertrophy defined by electrocardiogram, or more sensitively by echocardiography, is associated with a substantially worse long-term outcome that includes a higher risk of sudden cardiac death. The risk of cardiovascular disease, disability, and death in hypertensive patients also is increased markedly by concomitant cigarette smoking, diabetes, or elevated low-density lipoprotein; the coexistence of hypertension with these risk factors increases cardiovascular morbidity and mortality to a degree that is compounded by each additional risk factor. Since the purpose of treating hypertension is to decrease cardiovascular risk, other dietary and pharmacological interventions may be required.
Pharmacological treatment of patients with hypertension associated with elevated diastolic pressures reduces morbidity and mortality from cardiovascular disease. Effective antihypertensive therapy markedly reduces the risk of strokes, cardiac failure, and renal insufficiency due to hypertension. However, reduction in risk of myocardial infarction may be less impressive.
Nonpharmacological therapy is an important component of treatment of all patients with hypertension. In some stage 1 hypertensives, blood pressure may be adequately controlled by a combination of weight loss (in overweight individuals), restricting sodium intake, increasing aerobic exercise, and moderating consumption of alcohol. These lifestyle changes, though difficult for many to implement, may facilitate pharmacological control of blood pressure in patients whose responses to lifestyle changes alone are insufficient.
Arterial pressure is the product of cardiac output and peripheral vascular resistance. Drugs lower blood pressure by actions on peripheral resistance, cardiac output, or both. Drugs may reduce the cardiac output by inhibiting myocardial contractility or by decreasing ventricular filling pressure. Reduction in ventricular filling pressure may be achieved by actions on the venous tone or on blood volume via renal effects. Drugs can reduce peripheral resistance by acting on smooth muscle to cause relaxation of resistance vessels or by interfering with the activity of systems that produce constriction of resistance vessels (e.g., the sympathetic nervous system). In patients with isolated systolic hypertension, complex hemodynamics in a rigid arterial system contribute to increased blood pressure; drug effects may be mediated by changes in peripheral resistance but also via effects on large artery stiffness. Antihypertensive drugs can be classified according to their sites or mechanisms of action
The hemodynamic consequences of long-term treatment with antihypertensive agents such as Ace inhibitors, Calcium channel blockers, Diuretics and Angiotensin receptor blockers provide a rationale for potential complementary effects of concurrent therapy with two or more drugs. The simultaneous use of drugs with similar mechanisms of action and hemodynamic effects often produces little additional benefit. However, concurrent use of drugs from different classes is a strategy for achieving effective control of blood pressure while minimizing dose-related adverse effects.
It is generally not possible to predict the responses of individuals with hypertension to any specific drug. For example, for some antihypertensive drugs, on average about two-thirds of patients will have a meaningful clinical response, whereas about one-third of patients will not respond to the same drug. There is considerable interest in identifying genetic variation in order to improve selection of antihypertensive drugs in individual patients. Polymorphisms in a number of genes involved in the metabolism of antihypertensive drugs have been identified, for example in the CYP family (phase I metabolism) and in phase II metabolism, such as catechol-O-methyltransferase. While these polymorphisms change the pharmacokinetics of specific drugs, it is not clear that there will be substantial differences in efficacy given the dose range available clinically for these drugs. Consequently, identification of polymorphisms that influence pharmacodynamic responses to antihypertensive drugs are of considerable interest. Polymorphisms influencing the actions of a number of classes of antihypertensive drugs, including angiotensin-converting enzyme inhibitors and diuretics, have been identified; so far, individual genes have not been found to have a major impact on pharmacodynamic responses. Genome-wide scanning may lead to identification of novel genes that are more clinically significant. Likewise, treatment may profit from an understanding of the molecular and genetic bases of hypertension.
Having been acquiring the milestone status in the medicine field; human beings have been failed to defeat HIV knocking at the thin line of life dragging it to the death. Centuries passed, the inventions went on the board defeating the fret of the diseases occupying the free spirit of human health and today it can be no wonder if man claims to capture the flipping wings of the viruses and the bacterial infections. A big question is the still unbeaten AIDS the abbreviation of Acquired Immune Deficiency Syndrome which challenges and mocks every precaution and every remedy proving futile.
AIDS virus attacks human immune system and damages it severely. This is one of the major causes leading death among the people of age 25-44. About an average estimation, annual crowd of 25 million becomes victim of HIV and pass away. With the assisted survey conducted under the supervision of World Health Organization; children fewer than 15 ages were crossing 2.1 million with HIV virus making 33.4 million people suffering with this disease.
After HIV attacks the human body, the immune system becomes vulnerable to the bacteria and the virus causing many diseases. Common bacteria, yeasts and many other viruses may not harm people having strong immune system but they can bring very fatal diseases in the people suffering AIDS. Common places of the HIV are tears, spinal fluid, vaginal fluid, breast milk; however all these are not the source of transportation of the virus, only breast milk and the vaginal fluid are found to be the transportation source.
After the series of the research conducted on the AIDS; the facts are found about HIV. Sexual contact including vaginal, oral or the sex brings the most proportion of the disease. Anyhow blood transfusion also becomes the major reason of the HIV. If the blood is donated by the HIV infected person, the receiver does receive the equal amount of the virus distribution. Therefore this is the most suggested to have HIV test before the blood is transported. If the blood is transferred without any suggested tests; there is a major risk of the person being prone to the disease. Third source is the transformation of the infection from the mother to the baby. If a pregnant woman is suffering with AIDS, the inborn infant will have it inherited.
Breast milk transfers the HIV virus to the infant. So, the milk feeding babies have all the viral and the bacterial diseases found in the woman. Other ways and the reasons of the virus transformation and these include the use of infected needle and the transplantation of the organ. If the transplanted organ is having the infection; the receiver does become the victim of AIDS.
There is a common confusion that if the organ receiver is the virus infected, the donor may become infected; this is not true and is a misconception. The donors are not in direct contact with the people receiving blood or the organ. Therefore the infection is never transferred from the receiver to the donor. However, the reversal of the concept is the reason. The receiver can be infected if the donor is likely to be suffering with HIV. Therefore, to reduce the risk the blood and the organ donators are gone through the screen tests.
There are rumor and the doubts about the virus being spread out through the casual contact like hugging. That’s an assumption; hugging does not cause HIV. Mosquitoes can never be a cause of the virus so; people making the windows closed and using the sprays all around for preventing them from AIDS; they must be aware of the fact this has nothing to deal with HIV.
People having fear of to be caught by the virus do not indulge in any activity which brings the human contact. They must know that AIDS is not transferred by the use of the things being touched by the people having HIV. Therefore social gatherings cannot be a reason of the disease spread through the sharing of edibles or the utensils.
Similarly the sports joining cannot bring AIDS to you. Often the AIDS suffering humans are avoided by the public and people do not like to share their common usage objects with them. In this way the society brings a common sense of inferiority to these individuals; therefore this is a duty of the state and the government to educate the people about the HIV and its risks, incidences and the causes. Thus AIDS having people suffer double torture; one is HIV and second is the cold attitude of the people living in society. These people cannot bring harm to the general crowd until are involved in one of the three major reasons as mentioned above.
When HIV enters in the human body system, it may not bring any symptom to appear even for ten years. Anyhow; the infected person can transfer the virus in this no symptom period. If the virus is not detected and treated at time; the infection can become severe and the disease enters in the serious phase. It starts with HIV infection and can become AIDS if goes untreated. Almost in all patients HIV progresses to AIDS. There is a small group of people who develop AIDS very slowly or never at all. This group is known as nonprogressors.
At present there is no treatment for AIDS. HAART is a therapy used for reducing the disease effects in the person suffering with the disease. HAART is a therapy which has its complications. It makes use of the medications, each with its side effects. Therefore doctors suggesting HAART must be careful recommending it.
Humanity is still waiting for the miraculous remedy which may bring the treatment of HIV.