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

When someone with untreated TB coughs or sneezes, the air is filled with droplets containing the bacteria. Inhaling these infected droplets is the usual way a person gets TB.

One of the most dreaded diseases of the 19th century, TB was the eighth leading cause of death in children 1 to 4 years of age during the 1920s. As the general standard of living and medical care improved in the United States, the incidence of TB decreased. By the 1960s, it wasn't even in the top 10 causes of death among children of any age group.

But TB is making a comeback in the United States today — particularly among the homeless, those in prison, and those rendered susceptible because of HIV infection.

Signs and Symptoms

In older infants and children, latent tuberculosis infection (LTBI), which is the first infection with the tuberculosis bacteria, usually produces no signs or symptoms. In addition, a chest X-ray shows no signs of infection.

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, due to lowered immunity), the bacteria become active.

Tuberculosis in older kids 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 might have coughing and the production of saliva, mucus, or phlegm that may contain blood.

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 kids emigrating to countries where TB is prevalent.

Contagiousness

Tuberculosis is contagious when it's airborne and can be inhaled by others. In general, kids are not considered contagious, and usually get the infection from infected adults.

The incubation period (the time it takes for a person to become infected after being exposed) varies from weeks to years, depending on the individual and whether the infection is primary, progressive, or reactivation TB.

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 kids with tuberculosis can be treated as outpatients and cared for at home. The treatment is usually in the form of oral medications. Rarely, 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.

Duration

Tuberculosis is a chronic disease that can persist for years if it isn't treated.

When to You Call the Doctor

Call the doctor if your child:

• has been in contact with a person who has (or is suspected to have) tuberculosis
• has persistent fever
• complains of sweating at night
• develops a persistent cough that doesn't respond to standard cough medications

Reviewed by: Joel Klein, MD
Date reviewed: November 2010
Originally reviewed by: Cecilia DiPentima, MD