THE HARMFUL EFFECTS OF HYPERTENSION
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Hypertension is a harmful disease condition with no specific perceptible symptoms in the early stage. It is otherwise known as a “silence killer” disease due to its unidentified symptoms at the early stage of development and these conditions affects both boxes. Hypertension can be defined in other ways by other researchers. Hypertension can be defined as the sustained elevation of arterial pressure with a systolic pressure above 140mmHg and a diastolic pressure above 90mmHg (Smith 1986).
Hypertension is of two types, these are the primary and secondary hypertension. In each case, if not properly managed can result in complications like cardiovascular accident, congestive heart failure and renal complications.
A number of factor increase the chances of this condition even with its no actual causes. This factor includes family history, obesity, sedentary lifestyle, cigarette smoking, high intake of salt and alcohol, stress, adrenal gland disorders and even drugs treatment.
Furthermore, hypertension once it occurs appropriate measures should be taken and investigations done for better management of the patient to prevent worse complications. These measures include knowing the previous medical history, drugs taken before arriving at the hospital.
Hypertension is no longer a problem of only the developed nations; it is present here with us. The reported prevalence of hypertension varies widely in the various parts of the world, as low as 34% in rural Indian men and as 72.5% in polish women.
Data published from Nigeria, Ghana, Cameroon and the Gambia have shown a higher prevalence of hypertension generally and a consistently higher prevalence in Urban than in rural areas.
The study of hypertension grades, the level of awareness of hypertensive status and associated risk factors has provided information on the current trends of hypertension in Nigeria. Assessment of modifiable risk factors from the study will serve as a basis for formulation and implementation of strategies that may reduce these risk factors in the populace. It will also sensitize the primary care physicians to identify high risk patient for appropriate counseling, timely intervention and referral when necessary thereby preventing complications of hypertension and avoidable death.
Hypertension is defined as a sustained elevation in blood pressure of an individual above levels considered normal for the individual’s age, sex, race, and body size. This definition implies that there has to be a reference value for an individual which is set arbitrarily based on the above mentioned bio-social indices, in other words there are various classification for the diagnosis of hypertension which actually erupted as a result of different studies by various research groups and which became adopted by the World Health Organization (WHO).
Grades of Hypertension
Hypertension has been grouped into the following grades:
- Normal Blood Pressure: Systolic blood pressure less than 130mmHg and diastolic blood pressure of 90mmHg -99mmHg.
- High Normal Blood Pressure: Systolic blood pressure of 130mmHg – 139mmHg and diastolic blood pressure of 85mmHg – 90mmHg.
- Grade 1 (mild hypertension): Systolic blood pressure of 40mmHg – 150mmHg and diastolic blood pressure of 90mmHg -99mmHg.
- Grade 2 (Moderate hypertension): Systolic blood pressure of 160mmHg – 175mmHg and diastolic blood pressure of 100mmHg – 109mmHg.
- Grade 3 (Severe hypertension): Systolic blood pressure of greater or 180mmHg and diastolic blood pressure of greater or 110mmHg.
Risk Factors for Hypertension
A number of risk factors for hypertension have been identified. Hypertension has been shown to increase with age being more prevalent in order person. Increased body mass index (BMI) [overweight and obesity] has been associated with the development of hypertension so also diabetes mellitus, heavy alcohol consumption and a family history of hypertension.
Other risk factors include heredity, race and tobacco use, salt, psychosocial stress, sedentary or inactive lifestyle, low potassium diet, contraceptive use and low birth weight.
Awareness of Hypertension
Hypertension is an increasingly important health issue, not just in the developed nations but also in the developing countries of the world including those of sub-Saharan Africa.
Hypertension once rare in West Africa is emerging as a serious endemic threat. Studies from various countries identify hypertension as a disease burden that requires concerted preventive and control efforts. It has been refereed to as “Silent Killer” disease because it often has no detectable symptoms while causing continuous and progressive damage to vital organs in the body. It is the leading global risk for mortality, being responsible for about 7.5 million death annually and the fifth leading contributor to the global burden of disease. No fewer than 4.33 million Nigerians aged 15 years and above have elevated blood pressure (systolic blood pressure of 160mmHg or above) or are (diastolic blood pressure of 95mmHg or above) or are on antihypertensive medicines. It is slightly greater in women that in men. It is greater in urban than rural communities. By Uzoma Geraldine Ifunanya, 2010.
Awareness of hypertension refers to having been informed of one’s hypertension status by a health professional. The level of awareness within the hypertensive population varies considerably in regions and countries of the world. Generally, it is higher in the developed countries.
A study on hypertension done at Ibadan, Nigeria 40% males and 60% females were aware of their hypertensive status. Therefore, it is necessary to create more awareness by way of education and to encourage people to be health conscious in order to increase the level of awareness of hypertension and thereby reducing the global burden of hypertension.
The Blood Vessels
The blood vessels of the human body carry the blood to all parts human tissues and organs.
There are five general classes of blood vessels in the cardiovascular system.
Arteries are elastic vessels that are very strong, able to carry blood from the heart under high pressure. They subdivided into thinner tubes that give rise to branched, finer arterioles. An artery’s wall consist of three distinct layers: the innermost tunica interna is made up of a layer of simple gummous epithelium known as endothelium. It rests on a connective tissue membrane with many elastic, collagenous fibres. The endothelium helps prevent blood clothing and may also help in regulating blood flow. It releases nitric oxide to relax the smooth muscle of the vessel. Vein walls are similar but not identical to artery walls.
The middle tunica media makes up most of an arterial wall including smooth muscle fibres and a thick elastic connective tissue layer. The outer tunica external (tunica adventitia) is thinner, mostly made up of connective tissue with irregular fibres. It is attached to the surrounding tissues. Smooth artery system. Vaso motor fibres receive impulse o contract and reduce blood vessel diameter. When inhibited, the muscle fibres relax and the vessels diameter increases changes in artery and arteriole diameters greatly affect blood flow and pressure. Layer arterioles also have three layers which get thinner as arterioles lead to capillary. Very small arteriole walls only have an endothelial lining and some smooth muscle fibres, with a small amount of surrounding connective tissue.
The smallest –diameter blood vessels are capillaries, which connect the smallest arterioles to the smallest venules. The walls of capillaries are also composed of endothelium and form the semi-permeable layer through which substances in blood are exchanged with substances in tissue fluids surrounding cells of the body.
Capillary walls have thin slits where endothelial cells overlap. These slits have various sizes, affecting permeability. Capillaries of muscle have smaller openings that those of the glands, kidneys and small intestine. Tissue with higher metabolic rates (such as muscles) has many more capillaries than those with slower metabolic rates (such as cartilage).
Some capillaries pass directly from arterioles to venues while others have highly branched networks. Pre-capillary sphincters control blood distribution through sphincters constricts or relax so that blood can follow specific pathways to meet tissue cellular requirements.
Gases, metabolic by- products and nutrient are exchanged between capillaries and the tissue fluid surrounding body cells. Capillary wall allow the diffusion of blood with high levels of oxygen and nutrients. They also allow high levels of carbondioxide and other wastes to move from the tissues into the capillaries. Plasma proteins usually cannot move through the capillary walls due to their large size, so they remain in the blood. Blood pressure generated when capillary walls contract provides force for filtration via hydrostatic pressure.
Blood pressure is strongest when blood leaves the heart and weaker as the distance from the heart increase because of friction (peripheral resistance) between the blood and the vessel walls. Therefore, blood pressure is highest in the arteries, less so in the arterioles, and lowest in the capillaries. Unusual events may cause excess fluid to enter spaces between tissue cells, often in response to chemicals such as histamine. If enough fluid leaks oil, lymphatic vessels can be overwhelmed, and affected tissues swell and becomes painful.
Venules are microscopic vessels that link capillaries to veins, which carry blood back to the atria. Vein walls are similar to arteries but have poorly developed middle layers, because they have thinner wall that are less elastic than arteries, their lumens have a greater diameter.
Many veins have flap like valves protecting inward from their linings. These valves often have tow structures that close if blood begins to back up in the vein. They aid in returning blood to the heart, opening if blood flow is toward the heart, but closing if it reverses. To keep blood flowing, the veins rely on the movement of nearby skeletal muscles, as well as the opening and closing of the valves within them. Therefore, a major structural difference between veins and arteries is that arteries do not have valves.
Veins also act as reservoirs for blood in certain conditions such as during arterial hemorrhage. Resulting venous constrictions help to maintain blood pressure by returning more blood to the heart, ensuring an almost normal blood flow.