Tuberculosis

Tuberculosis (popularly known as "TB") is a disease caused by the bacteria Mycobacterium tuberculosis. It mainly infects the lungs, although it can affect other organs as well.

Signs and Symptoms

In older infants and children, primary pulmonary tuberculosis (the first infection with the tuberculosis bacteria) usually produces no signs or symptoms, and a chest X-ray shows no signs of infection. Rarely, there may be enlargement of the lymph nodes and possibly some coughing.

In most cases, only a tuberculin skin test (used to figure out if someone has been infected by the tuberculosis bacteria) is positive, indicating that the child has been infected. Children with a positive tuberculin test, even if they show no disease, will usually need to receive medication.

This primary infection usually resolves on its own as a child develops immunity over a 6- to 10-week period. But in some cases, it can progress and spread all over the lungs (called progressive tuberculosis) or to other organs. This causes signs and symptoms such as fever, weight loss, fatigue, loss of appetite, and cough.

Another type of infection is called reactivation tuberculosis. Here, the primary infection has resolved, but the bacteria are dormant, or hibernating. When conditions become favorable (for instance, a lowered immunity), the bacteria become active. Tuberculosis in older children and adults may be of this type. The most prominent symptom is a persistent fever, with sweating during the night. Fatigue and weight loss may follow. If the disease progresses and cavities form in the lungs, the person may experience coughing and the production of saliva, mucus, or phlegm that may contain blood.

Tuberculosis Causes

All cases of TB are passed from person to person via droplets. When someone with TB infection coughs, sneezes, or talks, tiny droplets of saliva or mucus are expelled into the air, which could be inhaled by another person.

Once infectious particles reach the alveoli, small sacs in your lungs, another cell called the macrophage engulfs the TB bacteria.

Then the bacteria are transmitted to your lymph system and bloodstream and spread to other organs.

The bacteria further multiply in organs that have high oxygen pressures, such as the upper lobes of your lungs, your kidneys, bone marrow, and meninges—the membranelike coverings of your brain and spinal cord.

When the bacteria cause clinically detectable disease, you have TB.

People who have inhaled the TB bacteria, but in whom the disease is controlled are referred to as infected. They have no symptoms, frequently have a positive skin test, yet cannot transmit the disease to others.

Risk factors for TB include the following:

HIV infection

Low socioeconomic status

Alcoholism

Homelessness

Crowded living conditions

Diseases that weaken the immune system

Migration from a country with a high number of cases

Health care workers

Prevention

The prevention of TB depends on:

Avoiding contact with those who have the active disease.

Using medications as a preventive measure in high-risk cases.

Maintaining good living standards.

New cases and potentially contagious patients are identified through proper use and interpretation of the tuberculin skin test.

A vaccine called BCG (Bacille Calmette-Guérin) is considered controversial because it isn't very effective in countries with a low incidence of TB. For this reason, BCG isn't usually given in the United States. However, it may be considered for children emigrating to countries where TB is prevalent.

Treatment

A doctor may recommend hospitalization for the initial evaluation and treatment of TB, especially if:

The child is a young infant.

There are severe drug reactions.

There are other diseases along with TB.

However, most children with tuberculosis can be treated as outpatients and cared for at home. The treatment is usually in the form of oral medications. In some cases, three or four drugs may be prescribed.

Even though treatment may require months to complete, it's vitally important that the full course of medications be taken in order for tuberculosis to be cured.