Tuberculosis of Lung or Pulmonary Tuberculosis: Causes, Symptoms, Types, Treatment, Pathophysiology, Epidemiology, Diagnosis
Almost all of us have suffered from various degrees of cough and cold at some point of our lives. While most of them are harmless and can be resolved quite easily, some of them may be an indication of something more serious. Tuberculosis is one such disease that infects thousands of people all over the globe. While resolution of the disease is subject to extensive treatment over a long period of time, most people do not take the condition seriously until it is too late. It is, therefore, quite important to diagnose the disease on time and get properly treated.
What is Tuberculosis of Lung or Pulmonary Tuberculosis?
Caused by Mycobacterium tuberculosis. Tuberculosis is a highly contagious disease which can affect any part of the body. Based on the part of the body where the bacteria have infected, tuberculosis can be classified into two heads- pulmonary and extra pulmonary tuberculosis. While extra pulmonary tuberculosis generally affects the other parts of the body, Pulmonary Tuberculosis affects the lungs. As tuberculosis of lungs or pulmonary tuberculosis is contagious, it can easily spread from one person to another by means of the infected sputum.
Types of Tuberculosis of Lung or Pulmonary Tuberculosis
Tuberculosis can be broadly classified into two categories- pulmonary tuberculosis and extra pulmonary tuberculosis. Tuberculosis of lungs or pulmonary tuberculosis can be further sub divided into five kinds, viz-
Primary Tuberculosis Pneumonia
Highly infectious, this is a rare kind of tuberculosis more likely to affect young children, the elderly population and people with immunosupression such as HIV, AIDS or patients undergoing corticosteroid therapy. Patients affected with this kind of TB are likely to suffer from high fever accompanied by a "productive cough".
This kind of Tuberculosis can be most often resolved without special kind of treatment; however, two out of every three patients are likely to develop active pulmonary tuberculosis within five years. This kind of TB is found to develop soon after a person is initially infected, with the granuloma which is positioned at the edge of the lung splitting into the area between the chest wall and the lungs, also known as pleural space. It is usual for the chest X-Ray of such a patient to show a significant amount of fluid in this area. The amount of fluid is likely to increase after it has been infected with bacteria. Shortness of breath, mild fever and a sharp pain in the chest are common manifestations of this kind of TB.
Involving the upper lobes of the lungs, the infecting bacteria gives rise to cavities, leading to progressive lung destruction. This kind of TB occurs as a result of the lungs being highly oxygenated and this is perhaps the reason why patients suffering from reactivation diseases are more likely to be affected. Patients are likely to manifest symptoms such as, night sweats, weight loss, fever, hemoptysis and weakness. There are also high probabilities of the patient developing TB Empyema if the disease spreads to the pleural area.
The appearance of small nodules spaced throughout the lungs having the appearance of millet seeds accounts for the term 'miliary'. Occurring shortly after the initial infection, patients suffering from this disease are seen suffering from high fever, weight loss, night sweats and may even be in danger of dying. Detection might prove to be difficult as the initial X-ray of the chest may seem to be normal.
This kind of TB is highly infectious and affects the larynx or the vocal cord area of the patients.
Symptoms of Tuberculosis of Lung or Pulmonary Tuberculosis
Patients suffering from latent tuberculosis of lungs or latent pulmonary tuberculosis are unlikely to manifest any major symptoms; however, patients suffering from active Tuberculosis of Lung manifest the following symptoms-
- Patients are likely to suffer from persistent coughing, accompanied with thick, cloudy and bloody mucus for more than a period of two weeks.
- Patients are also likely to manifest night sweats accompanied by chills and fever.
- Patients also suffer from a persistent sense of weakness and fatigue.
- Loss of appetite accompanied by unexplained loss of weight can also be considered as another symptom.
- Patients also suffer from a sharp pain in the chest and a shortness of breath.
Other disease such as lung cancer and pneumonia may also manifest similar symptoms as that of Pulmonary TB. It is therefore important to ascertain the actual cause of the disease through proper diagnosis.
Prognosis of Tuberculosis of Lung or Pulmonary Tuberculosis
Pulmonary Tuberculosis is likely to be resolved with proper treatment. Although there could be presence of few complications and the rate of recurrence ranges between 0-14 % as per the studies involving DOT treatment. In countries with high rates of Tuberculosis, recurrence can be mainly attributed to re-infection while those countries with low rates of Tuberculosis, recurrences occur due to relapse. Involvement of extra pulmonary organs, old age, a record of previous such treatment and the like account for poor prognosis.
Epidemiology of Tuberculosis of Lung or Pulmonary Tuberculosis
According to the estimates released by the World Health Organization, the highest number of people infected with Pulmonary Tuberculosis in 2010 was from India, South Africa, Pakistan, China and Indonesia. While China and India accounted for 38% of the reported cases, India alone was responsible for 26%. Though the number of infected people have reduced from 2006 onwards, about 1 in every 3 people are found to be suffering from this disease. Around 8.8 million deaths occurred in the year 2010 due to the disease, out of which 1.1 million were HIV negative people.
Causes of Tuberculosis of Lung or Pulmonary Tuberculosis
Mycobacterium tuberculosis can be credited to be the major causative agent of Pulmonary Tuberculosis. These are slow growing bacteria that are found likely to thrive in those areas of the body that are rich in blood and oxygen like the lungs. The bacteria are found to easily spread from one person to another. This means a healthy person coming in contact with a coughing or sneezing of patient with Pulmonary Tuberculosis has high probability of developing the disease.
A majority of people infected with primary Pulmonary TB recover from the disease without any special medical treatment. However, the bacteria can remain dormant for a number of years and then manifest themselves in an active form of the disease.
Pathophysiology of Tuberculosis of Lung or Pulmonary Tuberculosis
People are likely to be infected with Mycobacterium tuberculosis when they are exposed to infected aerosols. A single cough of an infected person has the capability of generating around 3000 droplets with as many as 10 bacilli which can initiate the infection with the organisms. The incubation period for the infection is 2 to 12 weeks. Pulmonary Tuberculosis is the most common form of TB with the statistics being around 85% of the reported cases. This kind of bacteria infects those areas of the body that have high oxygen content which is probably the reason for the occurrence of the infection is more common in the lungs.
Diagnosis of Tuberculosis of Lung or Pulmonary Tuberculosis
Successful treatment of Pulmonary Tuberculosis is subject to proper diagnosis. Doctors are likely to conduct certain tests in order to ensure the degree of the disease. Diagnosis is generally of three kinds, viz-
- Skin test- In this examination, the doctor is likely to inject a small quantity of Purified Protein Derivative (PPD) tuberculin under the skin upon which patients will be asked to return back after a couple of days in order to observe the reaction. Reddening of the injected area along with a hard swollen skin of about five millimeters might be an indication of Pulmonary Tuberculosis.
- Blood test- A sample of blood from the infected person is subjected to certain tests in the laboratory for presence of the tuberculosis bacterium.
- X- Ray- Doctors might also suggest X-rays in order to detect accumulation of fluid in the pleural area or the development of nodule like structure.
Treatment of Tuberculosis of Lung or Pulmonary Tuberculosis
It is essential to treat Pulmonary Tuberculosis as early as possible in order to reduce the damages the disease inflicts on the body. While latent tuberculosis is unlikely to manifest any symptoms and does not get transmitted from the infected person to others, it is equally important to get treated for it. Active Pulmonary Tuberculosis is generally treated by a combination of four medicines until signs of improvement are observed or the disease is completely resolved which may take a period of four to nine months or even longer.
DOT or Direct Observation Therapy is another successful treatment adopted for treating patients suffering from Active Pulmonary Tuberculosis. Patients are required to take all the dosages of antibiotics in the presence of the healthcare expert which proves to be helpful in the long run.
It is imperative to continue taking the medicines even if one finds an improvement in the condition. Not doing so can lead to the bacteria becoming resistant to drugs which pose a greater challenge in the treatment of the disease.
Prevention of Tuberculosis of Lung or Pulmonary Tuberculosis
Prevention of Pulmonary Tuberculosis focuses on two aspects- not allowing a healthy person to be infected and preventing a person suffering from latent Pulmonary Tuberculosis from developing Active Tuberculosis of the lungs. There are certain preventive measures that one could take in order to avoid being infected with Mycobacterium tuberculosis-
- BCG Vaccine or the Bacillus-Calmette-Guerin is used for immunization against the bacteria and possible infection as an outcome. This vaccine is ideal for children; adults, however, might not show favorable results.
- People need to avoid coming in contact with the sputum of the infected person.
- It is also imperative to maintain certain basic hygiene conditions in order to ensure better protection from Mycobacterium tuberculosis.
Though Tuberculosis of lung is a highly contagious disease, proper treatment and certain preventive measures are likely to prove quite beneficial.