What is tuberculosis?
Tuberculosis (TB) is an infectious disease caused by bacteria whose scientific name is Mycobacterium tuberculosis. It was first isolated in 1882 by a German physician named Robert Koch who received the Nobel prize for this discovery. TB most commonly affects the lungs but also can involve almost any organ of the body. Many years ago, this disease was referred to as "consumption" because without effective treatment, these patients often would waste away. Today, of course, tuberculosis usually can be treated successfully with antibiotics.
There is also a group of organisms referred to as atypical tuberculosis. These involve other types of bacteria that are in the Mycobacterium family. Often, these organisms do not cause disease and are referred to a "colonizers," because they simply live alongside other bacteria in our bodies without causing damage. At times, these bacteria can cause an infection that is sometimes clinically like typical tuberculosis. When these atypical mycobacteria cause infection, they are often very difficult to cure. Often, drug therapy for these organisms must be administered for one and a half to two years and requires multiple medications.
A person can become infected with tuberculosis bacteria when he or she inhales minute particles of infected sputum from the air. The bacteria get into the air when someone who has a tuberculosis lung infection coughs, sneezes, shouts, or spits (which is common in some cultures). People who are nearby can then possibly breathe the bacteria into their lungs. You don't get TB by just touching the clothes or shaking the hands of someone who is infected. Tuberculosis is spread (transmitted) primarily from person to person by breathing infected air during close contact. There is a form of atypical tuberculosis, however, that is transmitted by drinking unpasteurized milk. Related bacteria, called Mycobacterium bovis, cause this form of TB. Previously, this type of bacteria was a major cause of TB in children, but it rarely causes TB now since most milk is pasteurized (undergoes a heating process that kills the bacteria)
What happens to the body when a person gets TB?
When the inhaled tuberculosis bacteria enter the lungs, they can multiply and cause a local lung infection (pneumonia). The local lymph nodes associated with the lungs may also become involved with the infection and usually become enlarged. The hilar lymph nodes (the lymph nodes adjacent to the heart in the central part of the chest) are often involved.
In addition, TB can spread to other parts of the body. The body's immune (defense) system, however, can fight off the infection and stop the bacteria from spreading. The immune system does so ultimately by forming scar tissue around the TB bacteria and isolating it from the rest of the body. Tuberculosis that occurs after initial exposure to the bacteria is often referred to as primary TB. If the body is able to form scar tissue (fibrosis) around the TB bacteria, then the infection is contained in an inactive state. Such an individual typically has no symptoms and cannot spread TB to other people. The scar tissue and lymph nodes may eventually harden, like stone, due to the process of calcification of the scars (deposition of calcium from the bloodstream in the scar tissue). These scars often appear on x-rays and imaging studies like round marbles and are referred to as a granuloma. If these scars do not show any evidence of calcium on x-ray, they can be difficult to distinguish from cancer.
Sometimes, however, the body's immune system becomes weakened, and the TB bacteria break through the scar tissue and can cause active disease, referred to as reactivation tuberculosis or secondary TB. For example, the immune system can be weakened by old age, the development of another infection or a cancer, or certain medications such as cortisone, anticancer drugs, or certain medications used to treatarthritis or inflammatory bowel disease. The breakthrough of bacteria can result in a recurrence of the pneumonia and a spread of TB to other locations in the body. The kidneys, bone, and lining of the brain and spinal cord (meninges) are the most common sites affected by the spread of TB beyond the lungs.
What is bronchitis?
Bronchitis is inflammation of the air passages within the lungs. It occurs when the trachea (windpipe) and the large and small bronchi (airways) within the lungs become inflamed because of infection or other causes.
What are the symptoms of bronchitis?
Some of the Symptoms include:
coughing up extra mucus, sometimes with blood
inflammation of the bronchi (branches of the airways below the trachea)
swelling (edema) of the bronchial walls
blockage of the alveoli
difficulty breathing (due to above symptoms)
blocked/runny nose (may be associated with bronchitis of some causes but is not part of it).
What is Asthma?
Asthma is a chronic medical condition. It has been defined by the National Heart, Lung and Blood Institute of the United States of America as a common chronic disorder of the airways that is complex and characterized by variable and recurring symptoms, airflow obstruction, bronchial hyperresponsiveness (bronchospasm), and an underlying inflammation. The interaction of these features of asthma determines the clinical manifestations and severity of asthma and the response to treatment.
Public attention in the developed world has recently focused on asthma because of its rapidly increasing prevalence, affecting up to one in four urban children.
What are its signs and symptoms?
Because of the spectrum of severity within asthma, some asthmatics only rarely experience symptoms, usually in response to triggers, whereas other more severe asthmatics may have marked airflow obstruction at all times.
Asthma exists in two states: the steady-state of chronic asthma, and the acute state of an acute asthma exacerbation. The symptoms are different depending on what state the asthmatic is in.
Common symptoms of asthma in a steady-state include: nighttime coughing, shortness of breath with exertion but no dyspnea at rest, a chronic 'throat-clearing' type cough, and complaints of a tight feeling in the chest. Severity often correlates to an increase in symptoms. Symptoms can worsen gradually and rather insidiously, up to the point of an acute exacerbation of asthma. It is a common misconception that all asthmatics wheeze-some asthmatics never wheeze, and their disease may be confused with another Chronic obstructive pulmonary disease such as emphysema or chronic bronchitis.
An acute exacerbation of asthma is commonly referred to as an asthma attack. The cardinal symptoms of an attack are shortness of breath (dyspnea), wheezing and chest tightness. Although the former is "often regarded as the sine qua non of asthma. some patients present primarily with coughing, and in the late stages of an attack, air motion may be so impaired that no wheezing may be heard.When present the cough may sometimes produce clear sputum. The onset may be sudden, with a sense of constriction in the chest, breathing becomes difficult, and wheezing occurs (primarily upon expiration, but can be in bothrespiratory phases). It is important to note inspiratory stridor without expiratory wheeze however, as an upper airway obstruction may manifest with symptoms similar to an acute exacerbation of asthma, with stridor instead of wheezing, and will remain unresponsive to bronchodilators.
Signs of an asthmatic episode include wheezing, prolonged expiration, a rapid heart rate (tachycardia), and rhonchous lung sounds (audible through a stethoscope). During a serious asthma attack, the accessory muscles of respiration (sternocleidomastoid and scalene muscles of the neck) may be used, shown as in-drawing of tissues between the ribs and above the sternum and clavicles, and there may be the presence of a paradoxical pulse (a pulse that is weaker during inhalation and stronger during exhalation), and over-inflation of the chest.
During very severe attacks, an asthma sufferer can turn blue from lack of oxygen and can experience chest pain or even loss of consciousness. Just before loss of consciousness, there is a chance that the patient will feel numbness in the limbs and palms may start to sweat. The person's feet may become cold. Severe asthma attacks which are not responsive to standard treatments, calledstatus asthmaticus, are life-threatening and may lead to respiratory arrest and death.
Though symptoms may be very severe during an acute exacerbation, between attacks an asthmatic may show few or even no signs of the disease
What is Lung abscess?
Lung abscess is necrosis of the pulmonary tissue and formation of cavities (more than 2 cm containing necrotic debris or fluid caused by microbial infection.
This pus-filled cavity is often caused by aspiration, which may occur during altered consciousness.Alcoholism is the most common condition predisposing to lung abscesses.
Lung Abscess is considered primary(60%) when it results from existing lung parenchymal process and is termed secondary when it complicates another process e.g. vascular emboli or follows rupture of extrapulmonary abscess into lung.
What are the signs and symptoms of Lung abscess?
Onset of symptoms is often gradual, but in necrotizing staphylococcal or gram-negative bacillary pneumonias patients can be acutely ill.Cough, fever with shivering and night sweats are often present. Cough can be productive with foul smelling purulent sputum (Ëœ70%) or less frequently with blood (i.e. hemoptysis in one third cases). Affected individuals may also complaint chest pain, shortness of breath, lethargy and other features of chronic illness.
Patients are generallycachectic at presentation. Finger clubbing is present in one third of patients.Dental decay is common especially in alcoholics and children. On examination of chest there will be features of consolidation such as localised dullness on percussion,bronchial breath sound etc.
For advance information on Respiratory disease
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