Tuberculosis- pulmonary
Overview
Pulmonary tuberculosis (TB) is a contagious bacterial infection that mainly involves the lungs, but may spread to other organs.
Symptoms
* Limited to minor cough and mild fever, if apparent * Fatigue * Unintentional weight loss * Coughing up blood * Fever and night sweats * Phlegm-producing cough Additional symptoms that may be associated with this disease: * Wheezing * Excessive sweating, especially at night * Chest pain * Breathing difficulty
Causes
Pulmonary tuberculosis is caused by a bacteria called Mycobacterium tuberculosis (M. tuberculosis). You can get tuberculosis by breathing in air droplets from a cough or sneeze of an infected person. The primary stage of the infection is usually asymptomatic (without symptoms). In the United States, most people will recover from primary TB infection without further evidence of the disease. However, in some cases, the disease may become active within weeks after the primary infection, or it may lie dormant for years and later reappear. The following are at higher risk for active TB: * Elderly * Infants * Persons with weakened immune systems, for example due to AIDS, chemotherapy, or antirejection medicines given after a organ transplant Your risk of contracting TB increases if you: * Are in frequent contact with people who have the disease * Live in crowded or unsanitary living conditions * Have poor nutrition The following factors that may increase the rate of tuberculous infection in a population: * Increase in HIV infections * Increase in number of homeless individuals (poor environment and poor nutrition) * The appearance of drug-resistant strains of TB In the United States, there are approximately 10 cases of TB per 100,000 people. However, rates vary dramatically by area of residence and socioeconomic class. See also: * Disseminated tuberculosis (affects the whole body) * Atypical mycobacterial infection
Prevention
TB is a preventable disease, even in those who have been exposed to an infected person. Skin testing (PPD) for TB is used in high risk populations or in individuals who may have been exposed to TB, such as health care workers. A positive skin test indicates prior TB exposure. Preventive therapy should be discussed with your doctor. Individuals exposed to tuberculosis should be skin tested immediately and a follow-up test should be done at a later date, if the initial test is negative. Prompt treatment is extremely important in controlling the spread of tuberculosis for those who have already progressed to active TB disease. A BCG vaccination to prevent TB is given in some countries with a high incidence of TB, but its effectiveness remains controversial. It is not routinely used in the United States. People who have had BCG may still be skin tested for TB and results of testing (if positive) discussed with one's doctor.
Prognosis
Symptoms may improve in 2 to 3 weeks. A chest x-ray will not show this improvement until later. Prognosis is excellent if pulmonary TB is diagnosed early and treatment is begun.
Treatment
The goal of treatment is to cure the infection with drugs that fight the tuberculosis bacteria. The intial treatment may involve a combination of many drugs. It is continued until lab tests show which medicine works best. Treatment usually lasts for 6 months, but longer courses may be needed for persons with AIDS or whose disease responds slowly. You may need to be admitted to a hospital to prevent the spread of the disease to others until you are no longer contagious. Incomplete treatment of TB infections (such as failure to take medications for the prescribed length of time) can contribute to the emergence of drug-resistant strains of bacteria.