CARDIOVASCULAR DSORDERS

A cardiovascular disorder (CVD) is the leading cause of untimely death in man.

1. Leukemia

It is characterized by uncontrolled production of leukocytes. As a result number of abnormal WBC5 greatly increases in the circulating blood. This is caused by a cancerous mutation of a myelogenous or lymphogenous cell. Myelogenous cells or bone marrow cells are in the bone marrow and may spread throughout the body, so that WBC is produced in many other organs. This WBC is not completely differentiated and so is defective.

Types of Leukemia: Leukemia are of different types depending upon the type of white blood cells, which are undifferentiated and being produced at a faster than normal rate. These may be neutrophilic leukemia, eosinophilic leukemia, basophilic leukemia, monocytic or lymphocytic leukemia, hairy cell leukemia. Leukemia is a serious disorder and the victim needs change of blood regularly. It can be cured by bone marrow transplant which in most cases effective, but a very expensive treatment. The ratio of occurrence is 8% in males and 7% in females. Leukemia patients are anemic, suffer from brain hemorrhage, and there is insufficient body defense mechanisms.

2.  Thalassemia

The word thalassemia consists of two Greek words Thallassa, the sea, haema, blood. It is also called Cooley’s anaemia after the name of Thomas B. Cooley, an American pediatrician (the physician who treats children).

The thalassemia syndromes are a heterogeneous group of disorders. It is transmitted genetically. It is characterized by lack of or depressed synthesis of either the alpha or beta globin chain of haemoglobin. It is characterized by the presence of microcytes by spleenomegal i.e. enlargement of spleen and by changes in the bones and skin, and severe anaemia.

This disease is more common in Mediterranean countries and parts of Africa and Southeast Asia. It can be cured by bone marrow transplant which is very expensive and does not give 100% cure rate. Haemoglobin molecule in most cases does not have beta chain instead of it F (Foetal) haemoglobin chain is present.

3.  Edema

The term edema means increased fluid in the interstitial tissue spaces. The excess of fluid may be inside or outside the cells. The intracellular edema is caused by osmosis of water into the cell. The extra-cellular edema is caused by:

(a) Abnormal leakage of fluid from the blood capillaries or failure of the lymphatic system to return from the interstitial fluid.

(b) Renal retention of sodium and water are clearly contributory factor of edema. Edema may occur at different sites e.g. subcutaneous edema, and pulmonary edema. Edema of the brain may be localized to sites of injury. Severe generalized edema is called anasarca.

Edema disturbs the exchange and concentration of minerals and ions in the blood and body cells. It affects blood pressure, increased heart beat etc. Pulmonary edema can cause death by interfering with normal ventilatory function. Brain edema is serious and can be rapidly fatal. )

4. Artificial Pace Maker

Sino- atrial node (SA node) is called a pace maker. It is responsible for initiating the impulses which trigger the heart beat rate. If there is some block in the flow of the electrical impulses or if the impulses initiated by SA node are weak it may lead to death of a person. So an artificial pace maker is used for the SA node to excite the heart. The artificial pace maker is battery operated. For example a four volt pace maker may be implanted in the flesh under the arm. It emits electric impulses 72 times a minute. A plastic coated wire carries the impulse through a vein to the right atrium, where its special tip is embedded in the heart’s pace maker.

Or if AV pathway is blocked the electrodes of artificial pacemaker are attached to the ventricle. Then this pacemaker provides continued rhythmic impulses that take over the control of the ventricles.

5. Blue Babies

The placenta provides the means by which the foetus obtains oxygen. At birth important changes take place in the circulation, associated with the fact that the respiratory function of the placenta is taken over by the lungs. In the foetus the umbilical vein conveys oxygenated blood to the posterior vena cava where it enters the right atrium of the heart. The lungs are functionless and most of the blood bypass them by flowing through the foramen ovule, a hole which, in fact, connects the right and left atria, and the ductus arteriosus, a vessel linking the pulmonary artery with the aorta. As a result of various pressure changes and nervous reflexes triggered principally by the rise in the partial pressure of oxygen in the blood when the baby takes its first breath, the foramen ovule and ductus arteriosus close soon after birth. The result is that from now on all the blood returning to the right atrium is sent to the lungs. Failure of the foramen ovule and or ducts arteries to close results in a ‘blue baby; a proportion of the blood continues to bypass the lungs, resulting in inadequate oxygenation of the tissues. Thus mixed blood is supplied to the body of new born babies resulting in the blueness of the skin i.e. cyanosis, thus the name “blue babies.”

6. Hypertension

Hypertension is a condition of high blood pressure. Prolonged high blood pressure damages the lining of the blood vessels and due to continuous strain imposed on the heart leads to weakening heart muscles. As a result efficiency of pumping action of the heart declines. It needs more oxygen to pump blood. Blood may then be retained in the heart and lungs, and often leads to fatal condition called congestive heart failure.

It has been shown that men under the age of 50 years with a blood pressure of 170/100 are twice likely to die of coronary heart disease as men with normal blood pressure of about 120/80. High blood pressure itself is associated with a number of factors including stress, obesity, smoking, drinking alcohol and lack of exercise. There is also a genetic predisposition in some people. Some of these factors can obviously be avoided by changes in life style.

Drugs known as B -blockers can be used to reduce hypertension. Hypertension is sometimes called as silent killer because it may not be detected until stroke or heart attack occurs.

7. Thrombus Formation and Hypertension: A clot on the inner wall of a blood vessel is called a thrombus. A thrombus can even block blood flow through a vessel or it can break loose from the vessel wall and be carried through the circulatory system. Such a free swimming clot is called an embolus (plural: emboli). Thrombosis is the formation of thrombus. In western civilization, thromboembolism is a leading cause of death.

Cause of Thrombus Formation:

(a) Irritation or infection of leading blood vessel.

(b) Reduced rate of blood flow due to long period of inactivity.

(c) Pneumonia, tuberculosis and emphysema etc.

8. Atherosclerosis

Arthrosclerosis comes form two Greek words athere, porride, skeleoris, hardening. It is coexisting Atheroma and arteriosclerosis. Atherosclerosis is an arterial disease. This condition involves the formation of soft masses of fatty material in blood vessel linings. These fatty masses called contain large quantities of cholesterol. They often form in arteries, making the arterial lining much rougher than normal. These roughening tend to promote thrombus formation and leads problem with embolism. A plaque develops; it decreases the diameter of the blood vessel and impedes blood flow. The formation of calcium deposits in the plaque and degenerative change in the arterial wall lead to hardening of the artery Hardened. i.e., sclerotic arteries have lost their elasticity and are thus susceptible to rupture.

9. Heart Attack (Myocardial infarction)

Plaque also can break loose and circulate until it blocks a small blood vessel or its rough surfaces cause formation of a clot that blocks a vessel. This is especially devastating if the blocked vessel is one of the coronary arteries of the heart. The portion of the heart muscle denied of a blood supply lack of oxygen dies, and said to be infarction. The whole process is called myocra (heart muscle) infarction due to thromboembolism.

Angina Pectoris: If a coronary artery becomes partially blocked, the individual may suffer from angina pectoris (literally means chest pain) characterized by chest pains and or a radial pain in the left arm. Nitroglycerin or related drugs dilate blood vessels and help relieve the pain.

Precaution:

(a) Avoid too much food especially rich in cholesterol.

(b) Maintain normal body weight.

(c) Control blood pressure by regular walk and exercise.

(d) Do not smoke.

(e) Observe Islamic way of life.

10. Stroke

Stroke, heart attack and aneurysm (abnormal dilation of blood vessel) are associated with hypertension and Atherosclerosis. A cardiovascular accident (CVA), also called a stroke or cerebral infarction, often results when a small cranial (brain) arteriole bursts or is blocked by an embolus.

Stroke causes necrosis or death of the surrounding neural tissues owing to lack of oxygen. The effect of a stroke depends on how severe the damage is and where in the brain the stroke occurs.

11. Haemorrhage

Blood loss is termed as Haemorrhage. When a small cranial arteriole bursts it is called brain Haemorrhage. It is caused when the wall of the arteries become hard and lose its elasticity and by high blood pressure.

Precaution:

(a)  Blood pressure must be controlled within normal limits i.e. normal blood pressure must be maintained.

(b) Do not become overweight.

(c) Do not smoke.

(d) Do regular exercise.

(e) Avoid stress and tension.

It is not a closed circulatory system, nor does it have a pump. It is made up of a network of thin walled vessels that carry a clear fluid called lymph.