Tuberculosis or TB was very common in the U.S. before antibiotics were developed. At that time, it was called Consumption and was a major cause of death. It is still a common cause of death in developing countries. It is caused by the tiny, slow growing bacteria Mycobacterium tuberculosis. The bacteria lodges in the lungs and can become active immediately or wait months or years to emerge as an active infection. It is terminal if left untreated.
can attack many different parts of the body, but in developed countries, it is usually found in the lungs
. For that reason only the pulmonary
form of the disease will be discussed here.
Causes and Development; Contributing Risk Factors
TB is one of the few diseases that are spread in the air from the sick person coughing or breathing. The bacteria
ride in the air as tiny droplets that may stay airborne for hours. It is spread by inhaling these droplets. Because of this, patients with known TB must have special isolation precautions.
Active infections of TB can come from a new exposure to the bacteria or from reactivation of the disease from an old exposure.
People with weak immune systems are more likely to have active TB. This would include the elderly, children, people with HIV
, people with diabetes
, or anyone who has been "worn down" from lack of sleep or lack of proper nutrition.
The risk of Tuberculosis
(TB), especially among children, increases with the following risk factors: having a family history of tuberculosis infection going back two to three generations; having traveled abroad or having been exposed to foreign visitors; having contact with HIV-infected persons; having contact with current or previous prison inmates; and living in high-risk areas.
Signs and SymptomsPulmonary
TB is often so nearly asymptomatic (showing no signs or symptoms) that the patient may deny all symptoms except "not feeling well". However, the following symptoms are possible:
- A cough that does not go away is the most common symptom. The patient often ignores it and attributes it to smoking or a cold.
- A 'productive' cough, with yellow or green sputum (the material that is coughed up). At first, this is just a small amount first thing in the morning, but becomes more productive as the disease progresses.
- Dyspnea (shortness of breath) may result from damage to the lung by the bacteria
- Hemoptysis (coughing up blood) usually does not occur until the later stage of TB
- Unexplained weight loss
- Night sweats from a fever that spikes up at night and is down during the day.
Diagnosis and Tests
Diagnosis will almost certainly require lab tests and X-rays. It shares symptoms with many other respiratory infections. Since TB is not extremely common in the United States at this time, suspect other problems before you suspect TB.
- Presence of signs and symptoms
- Treatment for other respiratory infections has not cleared the problem
- The following would increase your suspicion of TB:
- History of exposure to someone with active TB
- History of previous active TB
- History of a positive TB test (also called a PPD test) in the past
- History of travel to a country where TB is common (most third world nations)
- History of working/living in a high-risk area: hospital, nursing home, prison, group home, drug treatment center, refugee camp, etc.
Treatment and Prevention
As with most things, prevention is best – especially since TB can be (extremely) hard to treat. If you are in the close company of others suspected of being at risk for TB, everyone should be screened annually for TB. The test is cheap and easy. If someone in your group has been exposed, REQUIRE them to go through the full course of treatment, which can take up to 9 months.