Tetralogy of Fallot - Essay Example

Running Head: Tetralogy of Fallot Student’s Name: Instructor’s Name: Course Code and Name: University: Date Assignment is due: Tetralogy of Fallot Introduction Tetralogy of Fallot is a heart defect among children that causes oxygen-poor blood to mix with oxygen-rich blood that is being pumped from the heart into the body’s entire circulatory system. As a result of this problem, the blood that leaves the heart has insufficient oxygen for all body tissues, causing a condition called hypoxemia. Long-term lack of oxygen in the body causes cyanosis, a condition characterized by bluing of the skin and the inner membranes of the nose and mouth. Without proper supply of oxygen-rich oxygen, the organs of the body cannot perform their functions well. There are four main abnormalities that cause Tetralogy of Fallot. The first one is right ventricular hypertrophy. In this condition, the pulmonary valve and pulmonary valve coming out of the right ventricle become blocked (Therrien & Siu, 2001). The resulting restriction in the flow of blood leads to an increase in the work and pressure of the right ventricle, causing hypertrophy or thickening off the right ventricular. Secondly, Tetralogy of Fallot may take the form of Ventricular Septal Defect (VSD). VSD is a hole that forms in the heart wall separating the two ventricles. The hole is often large enough to allow passage of oxygen-poor blood in the right ventricle to mix with the blood in the left ventricle. The poorly oxygenated blood ends up being pumped into the entire body (Helbing & Niezen, 1996). Thirdly, Tetralogy of Fallot may also take the form of abnormal positioning of the aorta. The aorta is the main artery that takes blood from the heart into the circulatory system. The abnormal positioning leads to insufficient supply of oxygen-rich blood into the entire circulatory system. The fourth manifestation of Tetralogy of Fallot is Pulmonary Valve Stenosis (PS). The main issue that occurs with tetralogy is the degree of occurrence of pulmonary valve stenosis. This is because VSD always occurs in all children with this abnormality. In the case of mild stenosis, minimal cyanosis takes place because there are high chances of blood traveling into the lungs. However, in the case of PS ranging from moderate to severe, only a small amount of blood can reach the lungs. This is because most of it is directed from the right ventricle to the right one through the VSD. Causes Tetralogy of Fallot is a defect that occurs when the fetus is developing, mostly during the first eight weeks of the fetal development; therefore, it is a congenital birth defect (Gatzoulis, 2009). Goldmuntz & Geiger (2001) indicate that the defect occurs when the fetal heart is separating into different valves, chambers and all the other structures that constitute a normal human heart. Nobody is sure why this error takes place. Sometimes, the heart defect arises sporadically, without any clear reason to account for its development (Abbott & Fraser, 2006). Some congenital defects appear to have a genetic link, occurring either as a result of a defective gene, environmental exposure or chromosome abnormality. This explains why the problem occurs more frequently in certain families and not others. One of the genetic links closely associated with this heart defect is deletion of chromosome 22q11 (Eldadah, Hamosh & Biery, 2001). This occurs in just a minority of babies with although it is thought to be highly common among those who have a severe form of Tetralogy of Fallot. Environmental exposure may take the form of maternal alcohol abuse during pregnancy, resulting in fetal alcohol syndrome (FAS). Additionally, mothers taking medications for control of seizures and mothers suffering from phenylketonuria (PKU) are highly likely to deliver a baby with tetralogy of Fallot. Symptoms Majority of infants suffering from tetralogy of Fallot develop cyanosis during the first year of life. The main symptoms include a dusky blue color that is easily noticeable on the lips, skin, and the mucous membrane covering the inner parts of the nose and mouth. Only a few infants, whose outflow in the right ventricle is severely obstructed, turn blue at birth. A few infants with this defect do not turn blue at all, especially in the case of mild pulmonary stenosis. Cyanosis may be quite subtle in some children. In fact, it may go undetected for a long period of time. A common symptom of the defect is a slow rate of growth and development, especially in the case of severe pulmonary stenosis. If tetralogy is not treated, puberty may be delayed. The children often tire rather easily and always start panting whenever they are exposed to any form of exertion. They may play only momentarily before lying or sitting down. Once a child with this defect is able to walk, he often squats in order to catch his breath before resuming physical activity. Squatting often increases pressure in the left ventricle and aorta transiently, leading to reduction in the movement of blood into the left ventricle as much of it starts moving into the lungs through the pulmonary artery. Children aged between 2 and 3 years may experience frequent episodes of hypercyanosis or extreme blue coloring. These children may become blue suddenly, have difficulty breathing, and can faint or become extremely irritable. Between of 20 and 70 % of children with this defect experience these spells. They may last between a few moments to several hours. The spells can happen during crying, straining, feeding or in the morning when the child is waking up. Medical tests and diagnosis Tetralogy of Fallot can sometimes go undiagnosed for many months (Vobecky, Williams & Trusler, 1993). Diagnosis of this condition remains one of the goals of routine medical checkups for infants. It is always beneficial for parents to remain on the lookout for symptoms of this condition and to consult their doctor immediately they notice any of them. Some of the symptoms that should be accorded emergency medical attention include trouble breathing, bluish discoloration, fainting, seizures and extreme weakness or fatigue. Sometimes the bluish color may be resolved by the time a child has been taken to the nearest medical facility. Even if this happens, the doctor immediately suspects a heart problem the medical tests that follow often focus on the identification of the underlying cause of cyanosis. Lab tests are often aimed at determining the hemoglobin and red blood cell counts. Both of them may be elevated in the body’s attempt to compensate for the inadequacy of oxygen in the body tissues. Electrocardiogram (ECG) is another medical test for measuring and recording the level of electrical activity in the heart. Abnormal recordings in this test indicate structural abnormalities within the heart. In the case of tetralogy of Fallot, the test will almost always reveal right ventricular hypertrophy (Babu-Narayan & Kilner, 2006). Additionally, an x-ray image can reveal both an abnormality in the aorta and the presence of a ‘boot-shaped heart’, which is a key indicator of an enlarged right ventricle (Geva, Sandweiss, Gauvrea & Lock, 2009). The child should also undergo echocardiography, a highly useful medical test that can reveal the presence of ventricular septal defect, the extent of pulmonary stenosis and many other defects that may be unanticipated. Cardiac catheterization may not be needed if the ECG, clinical and echocardiogram findings are done routinely. Cardiac catheterization is a highly invasive procedure that should be undertaken by cardiologists in special laboratories, whereby a patient is put under local anesthesia. Initially, this procedure was the only preferred mode of confirming the diagnosis. The procedure involves the insertion of a catheter in a blood vessel and advancing it up the inferior vena cava, right into the heart. An x-ray image is than taken after some dye has been infused into the catheter. The role of the dye is to identify the presence of pulmonary stenosis, ventricular septal effect, size of all pulmonary arteries and an overriding aorta. Treatment Surgery is the most commonly used procedure for correcting the heart problem. Additionally, the doctor may prescribe some medication for tet spells. Additionally, provision of information on future spells is also a part of the standard medical treatment procedure. The doctor often puts the child on his back, mainly in the knee-to-chest position, so as to increase aortic resistance. The increase in left ventricular and aortic pressure is necessary in order to reduce the amount of blood that rushes from the right ventricle into the septic hole. This increases the level of blood that flows into the lungs, thus facilitating access of many red blood cells in the body tissues. Some of the medications offered include metoprolol, phenylephrine and morphine, all of which help to decrease the severity and frequency of tet spells. The Surgical procedure for Tetralogy of Fallot The surgery for correcting the Tetralogy of Fallot is known as Blalock-Taussig operation (Khairy & Landzberg, 2004). This palliative procedure is aimed at increasing the volume of blood that flows into the lungs. Once the child’s heart is able to obtain enough blood supply, he can grow and attain an age at which a complete surgical repair can be undertaken. Blalock-Taussig operation entails the creation of a connection between the right pulmonary artery and the right subclavian artery. This relieves cyanosis and a dramatic improvement in a child’s health is realized. The timing of this operation is done on the basis of symptoms. In most cases, surgery for total correction is done within the first two years of the child’s life. The total correction surgery involves complete closure of the ventricular septum and opening up of the right ventricular stenosis. After these corrections, sufficient blood flows into the lungs; it is then oxygenated, and then pumped into the entire circulatory system. Over the last 20 years, operative mortality rates have dropped dramatically. However, this defect is also one of the most serious heart conditions among children since between 1 and 5% of all children undergoing the complete correction die during or soon after the procedure. Conclusion Tetralogy of Fallot is a serious heart condition for children. Research for this problem is still ongoing with regard to various issues, including its causes, symptoms, medical examination and tests, and treatment. Although it is not clear what causes it, a large number of cases have been associated with genetic links. This explains the reason why members of certain families acquire the disease more often than the rest of the population. There is a need for more research to be done in all areas of development of the disease in order to ascertain which corrective mechanisms are best ones to use. Particularly, research on the various surgical procedures such as Blalock-Taussig operation should be done in order to reduce the high number of children who die during or soon after the corrective surgery. References Abbott, M. & Fraser, R. (2006). Atlas of Congenital Cardiac Disease. London: Macmillan. Babu-Narayan, S. & Kilner, P. (2006). Ventricular Fibrosis Suggested by Cardiovascular Magnetic Resonance in Adults With Repaired Tetralogy of Fallot and Its Relationship to Adverse Markers of Clinical Outcome, Circulation,113, 405-413. Gatzoulis, M. (2009). Risk factors for arrhythmia and sudden cardiac death late after repair of tetralogy of Fallot: a multicentre study. The Lancet, 356, 9234, 975-981. Geva, T., Sandweiss, B., Gauvreau, K. & Lock, A. (2009). Factors associated with impaired clinical status in long-term survivors of tetralogy of Fallot repair evaluated by magnetic resonance imaging Journal of the American College of Cardiology, 43 (6), 1068-1074. Goldmuntz, E. & Geiger, E. (2001). NKX2.5 Mutations in Patients with Tetralogy of Fallot, Circulation, 104, 2565. Eldadah, Z. Hamosh, A. & Biery, N. (2001). Familial Tetralogy of Fallot caused by mutation in the jagged1 gene. Human Molecular Genetics, 10 (2), 163-169. Helbing, W. & Niezen, R. (1996). Right Ventricular Diastolic Function in Children with Pulmonary Regurgitation after Repair of Tetralogy of Fallot: Volumetric Evaluation by Magnetic Resonance Velocity Mapping. Journal of the American College of Cardiology, 28(7), 1827-1835. Khairy, P. & Landzberg, M. (2004). Value of Programmed Ventricular Stimulation after Tetralogy of Fallot Repair: A Multicenter Study. Circulation. 109, 1994-2000. Therrien, J. & Siu, C. (2001). Impact of Pulmonary Valve Replacement on Arrhythmia Propensity Late After Repair of Tetralogy of Fallot. Circulation.103, 2489. Vobecky, S., Williams, W. & Trusler,G. (1993). Survival analysis of infants under age 18 months presenting with tetralogy of Fallot, The Annals of Thoracic Surgery, 56, 944-949. Read More