Tuberculosis Undergraduate Essay Example for Free

Tuberculosis Undergraduate Essay Abstract Tuberculosis is a good example of the importance of the ecological balance between host and parasite in infectious disease. Hosts are not usually aware of pathogens that invade the body and are defeated. If defenses fail, however, hosts become very much aware of the resulting disease. Several factors may affect host resistance levels—the presence of other illness and physiological and environmental factors such as malnutrition, overcrowding, and stress. Tuberculosis is most commonly acquired by inhaling the tubercle bacillus. Only very fine particles containing one to three bacilli reach the lungs, where they are usually phagocytized by a macrophage in the alveoli. The macrophages of a healthy individual usually destroy the bacilli. I. Introduction Tuberculosis is or TB is an infectious disease that usually affects the lungs. The most common form is caused by Mycobacterium tuberculosis, a slender, rod-like bacterium commonly called the tubercle bacillus. The tubercle bacillus is very hardy, surviving when many other bacteria cannot. In addition to affecting the lungs, tuberculosis can affect almost all other organs of the body. Tuberculosis, which in the past called phthisis and consumption, has afflicted man for thousands of years. Evidence of the disease has been found in Egyptian mummies. Tuberculosis was once a leading cause of death in all age groups, but its severity has decreased with improved medical care and better living standards. Most persons have a natural resistance to the tubercle bacillus. Even though large numbers of persons, especially in cities, become infected by the bacillus early in life, only a small percentage actually develops the disease (Orrett Shurland, 2001). This paper intent to: (1) know the occurrence of tuberculosis and how it is being spread; (2) be aware of its symptoms and detection and; (3) figure out its treatment and control. II. Background Tuberculosis is an infectious disease caused by the bacterium Mycobacterium tuberculosis, a slender rod and an obligate aerobe. The rods grow slowly (20-hour generation time), sometimes form filaments and tend to grow in clumps. On the surface liquid media, their growth appears moldlike, which suggested the genus name Mycobacterium, from the Greek mykes, meaning fungus. These bacteria are relatively resistant to normal staining procedures. When stained by the ZiehlNeelson or Kinyoun technique that stains the cell with carbolfuchsin dye, they cannot be decolorized with a mixture of acid and alcohol and are therefore classified as acid-fast. This characteristic reflects the unusual composition of the cell wall, which contains large amounts of lipid materials (American Thoracic Society, 2000). These lipids might also be responsible for the resistance of mycobacteria to environmental stresses, such as drying. In fact, these bacteria can survive for weeks in dried sputum and are very resistant to chemical antimicrobials used as antiseptics and disinfectants. Tuberculosis is a good example of the importance of the ecological balance between host and parasite in infectious disease. Hosts are not usually aware of pathogens that invade the body and are defeated. If defenses fail, however, hosts become very much aware of the resulting disease. Several factors may affect host resistance levels—the presence of other illness and physiological and environmental factors such as malnutrition, overcrowding, and stress (Weiss, 2000). Tuberculosis is most commonly acquired by inhaling the tubercle bacilli reach the lungs, where they are usually phagocytized by a macrophage in the alveoli. The macrophages of a healthy individual usually destroy the bacilli. If they do not, the macrophages actually protect the microbe from the chemical and immunological defenses of the body, and many of the bacilli survive and multiply within the macrophage (American Thoracic Society, 2000). These macrophages eventually lyse, releasing an increased number of pathogens. The tubercle bacilli released from dying macrophages form a lesion. A hypersensitivity reaction against these organisms causes formation of a tubercle, which effectively walls off the pathogen. These small lumps are characteristics of tuberculosis and give the disease its name. Tubercles are composed of packed masses of tissue cells and the disintegration products of bacilli and leukytes; they usually have a necrotic center. Few bacteria are present in the tubercle (Diehl, 2003). The tubercle bacillus does not produce any injurious toxins. Tissue damage is mostly from the hypersensitivity reaction. As the reaction continues, the tubercle undergoes necrosis and eventually forms a caseous lesion that has a cheeselike consistency. If the caseous lesions heal, they become are called Ghon complexes. If the disease is not arrested at this point, the caseous lesions progress to liquefaction. An air-filled tuberculous cavity is formed from the caseous lesion. Conditions within the cavity favor the proliferation of the tubercle bacillus, which then grows for the first time extracellularly. Bacilli soon reach very large members, and eventually the lesion ruptures, releasing the microorganisms into the blood and lymphatic system (American Thoracic Society and Centers for Disease Control and Prevention, 2000). This condition of rapidly spreading infection that overwhelms the body’s remaining defenses is called miliary tuberculosis (the name is derived from the numerous millet seed-sized tubercles formed in the infected tissues). This condition leads to a progressive disease characterized by loss of weight, coughing (often with a show of blood), and general loss of vigor. (At one time, tuberculosis was commonly was known as consumption.) Even when patients are considered cured, tubercle bacilli often remain in the lung, and the disease may be reactivated. Reactivation may be precipitated by old age, poor nutrition, or immunosuppression. III. Discussion A. Occurrence and Spread When a person with tuberculosis coughs or sneezes, tiny droplets containing thousands of tubercle bacilli are sprayed into the air. The disease is spread when non-infected persons inhale the bacilli thus released into the air. A person can also contract tuberculosis by drinking unpasteurized milk from cows having the disease. This form of tuberculosis is caused by the bacterium Mycobacterium bovis. Resistance to tuberculosis depends largely upon the general health of the individual. Persons who are undernourished or weakened by disease are more likely to develop tuberculosis. Outbreaks tend to occur in areas with crowded living conditions, such as nursing homes and prisons (Centers for Disease Control and Prevention, 2003). About 90 percent of tuberculosis infections occur first in the lungs. Tuberculosis of the lungs is called pulmonary tuberculosis. When tubercle bacilli are inhaled into the lungs, they are either destroyed by white blood cells or surrounded by special cells and fibers in the infected area of the lung, forming tiny nodules called tubercles. If the immune system is effective, the bacteria are kept from multiplying and an active case of tuberculosis does not develop. In some cases, however, the bacteria enter the bloodstream or lymphatic system and are carried to other parts of the body. The bacteria usually lodge in the brain, kidneys, bones, or heart (Murray, 2000). B. Symptoms and Detection Early pulmonary tuberculosis commonly gives no specific warning. Later, fatigue, weight loss, or a low fever may be the only symptoms. In advanced stages, severe coughing, hoarseness, chest pain and the appearance of blood in the sputum (a mixture of saliva and discharges from the respiratory passages) can occur. If the patient is untreated and his resistance is low, large areas of lung tissue can be destroyed and there is considerable weight loss. The best way of detecting infection by tubercle bacilli is by means of a tuberculin test. In a tuberculin test, tuberculin—a liquid containing substance obtained from tubercle bacilli—is injected between the layers of the skin. After 48 to 72 hours, the point of injection is examined for redness and swelling (Centers for Disease Control and Prevention, 2003). A tuberculin test will reveal whether a person has been infected by tubercle bacilli, but it will not indicate whether he has an active case of the disease. Diagnosis of active tuberculosis can usually be made by a chest X ray and other tests. Diseased areas of the lungs usually cast a characteristic shadow on the X-ray film. Another method of diagnosis involves a microscopic examination of the patient’s sputum for the presence of tubercle bacilli (Centers for Disease Control and Prevention, 2003). C. Treatment and Control Prior to 1945, practically the only methods for treating tuberculosis were prolonged bed rest and (in advanced cases) immobilization of the infected lung by collapsing it. Since the time, drugs have been produced that can stop the tubercle bacilli from multiplying, thus allowing the natural defenses of the body to be effective. The most important of these drugs are streptomycin (INH). In addition, improved surgical techniques permit the safe removal of areas of the lung where infection persists despite treatment with drugs (American Thoracic Society, 2000). Most important in tuberculosis control is early detection, so that persons with the disease can be treated and isolated from others. A vaccine known as BCG can create immunity to tuberculosis. However, in the United States this vaccine is recommended only in special circumstances. One reason is that vaccinated persons react positively to a tuberculin test and therefore cannot be differential from infected persons. D. Planning and Goals The major goals for the patient include maintenance of a patient airway, increased knowledge about the disease and treatment regimen and adherence to the medication regimen, increased activity tolerance, and absence of complications. E. Nursing Interventions a.) Promoting Airway Clearance Copious secretions obstruct the airways in many patients with TB and interfere with adequate gas exchange. Increasing fluid intake promotes systematic hydration and serves as an effective expectorant. The nurse instructs the patient about correct positioning to facilitate airway drainage (Diehl, 2003). b.) Advocating Adherence to Treatment Regimen The multiple- medication regimen that a patient must follow can be quite complex. Understanding the medications, schedule, and side effects is important. The patient must understand that TB is a communicable disease and that taking medications is the most effective means of preventing transmission. The major reason treatment fails is that patients do not take their medications regularly and for the prescribed duration. The nurse carefully instructs the patient about important hygiene measures, including mouth care, covering the mouth and nose when coughing and sneezing, proper disposal of tissues, and hand hygiene (Diehl, 2003). c.) Promoting Activity and Adequate Nutrition Patients with TB are often deliberated from a prolonged chronic illness and impaired nutritional status. The nurse plans a progressive activity schedule that focuses on increasing activity tolerance and muscle strength. Anorexia, weight loss, and malnutrition are common in patients with TB. The patient’s willingness to eat may be altered by fatigue from excessive coughing, sputum production, chest pain, generalized debilitated state, or cost, if the person has few resources. A nutritional plan that allows for small, frequent meals may be required. Liquid nutritional supplements may assist in meeting basic caloric requirements (Centers for Disease Control and Prevention, 2003). F. Monitoring and Managing Potential Complications a.) Malnutrition This may be a consequence of the patient’s lifestyle, lack of knowledge about adequate nutrition and its role in health maintenance, lack of resources, fatigue, or lack of appetite because of coughing and mucus production. To counter the effects of these factors, the nurse collaborates with dietitian, physician, social worker, family, and patient to identify strategies to ensure an adequate nutritional intake and availability of nutritious food. Identifying facilities that provide meals in the patient’s neighborhood may increase the likelihood that the patient with limited resources and energy will have access to a more nutritious intake (Centers for Disease Control and Prevention, 2003). High-calorie nutritional supplements may be suggested as a strategy for increasing dietary intake using food products normally found in the home. Purchasing food supplements may be beyond the patient’s budget, but a dietitian can help develop recipes to increase calorie intake despite minimal resources. IV. Conclusion In conclusion, persons infected with tuberculosis develop cell-mediated immunity against the bacterium. This form of immune response, rather than humoral immunity, is because the pathogen is located mostly within macrophages. This immunity, involving sensitized T cells, is the basis for the tuberculin skin test. In this test, a purified protein derivative (PPD) of the tuberculosis bacterium, derived by precipitation from broth cultures, is injected continuously. If the injected person has been infected with tuberculosis in the past, sensitized T cells react with these proteins and a delayed hypersensitivity reactions appears in about 48 hours. This reaction appears as an induration (hardening) and reddening of the area around the injection site. Probably the most accurate tuberculin test is the Mantoux test, in which dilutions of 0.1 ml of antigen are injected and the reacting area of the skin is measured. A number of similar tests are also in common use. A positive tuberculin test in the very young is a probable indication of an active case of tuberculosis. In older persons, it might indicate only hypersensitivity resulting from a previous infection or vaccination, not a current active case. Nonetheless, it is an indication that further examination is needed, such as a chest X-ray for the detection of lung lesions and attempts to isolate the bacterium. References: 1. American Thoracic Society (2000). Diagnostic standards and classification of tuberculosis in adults and children. American Journal of Respiratory and Critical Care Medicine, 161 (4), 1376-1395. 2. American Thoracic Society and Centers for Disease Control and Prevention (2000). Targeted tuberculin testing and treatment of latent infection. American Journal of respiratory and Critical Care Medicine, 161 (4), S221-S247. 3. Centers for Disease Control and Prevention (2003). Essential components of a tuberculosis prevention and control program: recommendations of the Advisory Council for the Elimination of Tuberculosis. MMWR Modibity and Mortality Weekly Report, 44 (RR-11), 1-16. 4. Diehl, H. S. (2003). The Health of College Students. American Council on Education. Washington, DC. 5. Murray, J. F. (2000). Intensive Care: A Doctors Journal. University of California Press. Berkeley, CA. 6. Orrett, Fitzroy A. Shurland, Simone M. (2001).Knowledge and Awareness of Tuberculosis among Pre-University Students in Trinidad Journal of Community Health, Vol. 26. 7. Weiss, R. â€Å"TB troubles.† Science News 133:92-93, 2000. Discusses reasons for the recent increase in tuberculosis in the United States.