Tuberculosis and HIV/AIDS

Table of Contents

• Introduction
• Forms of TB
• TB and HIV
• Preventing TB
• TB Symptoms
• Detecting and Diagnosing TB
• TB Treatment
• TB and Pregnancy
• The Bottom Line

Introduction

Tuberculosis (TB) is an infection of the lungs and respiratory system. Along with HIV, TB is one of the world's leading causes of death due to disease. The Centers for Disease Control and Prevention (CDC) reports that, in 2010, close to nine million people became sick with TB and over 1.4 million died from TB worldwide. In the US, the number of new TB cases each year has been going down for eighteen straight years. However, there are still 10-15 million people in the US who are infected with TB.

TB is caused by a bacterium called Mycobacterium tuberculosis. It spreads from person to person when an infected person coughs, sneezes, laughs, or spits. Tiny droplets of fluid from the lungs are carried in the air and can be breathed in by someone nearby. Although it can affect many parts of the body, TB usually occurs in the lungs.

Forms of TB

Not everyone who is infected with TB bacteria develops "active" disease.

• Latent TB
  Most people with healthy immune systems can fight off TB bacteria, even after they breathe them in and are infected. People with latent or inactive TB have no symptoms. They neither feel sick nor spread the disease to other people. In some people, TB stays latent or inactive for their entire lives. But in other people, latent TB turns into active disease if their immune system is damaged or weakened, through things like HIV infection, cancer, or transplant surgery that requires taking drugs to suppress the immune system.
• Active TB
  Some people infected with TB develop active disease. Active TB usually causes symptoms like coughing and weight loss. People with active TB can spread it to others. Active TB may develop either soon after infection or years later when a person's immune system becomes weaker.

TB and HIV

People with weakened immune systems are more likely to develop active TB disease. This includes people living with HIV (HIV+), children, elderly people, and people who take drugs that suppress the immune system. Research shows that people living with HIV are at least ten times more likely to develop active TB disease than HIV-negative people. You can develop active TB with any CD4 count. Studies also show that TB can worsen HIV disease progression. Having active TB disease while HIV+ is an AIDS-defining condition.

Worldwide, TB is the leading cause of death in HIV+ people. The US government recommends that you be screened every year for TB if you are HIV+ by having a skin or blood test (see "Diagnosing TB," below).

Preventing TB

TB is spread through the air when an infected person coughs, sneezes or spits. It usually takes a long time for TB transmission to occur. Family members of people with TB, people living in the same house, health-care workers, and people who live in residential facilities like homeless shelters and prisons are most likely to get TB. People with latent (not active) TB do not spread the disease. Once a person with active TB starts treatment (see "TB Treatment" below), they usually cannot spread the disease after 2-3 weeks on treatment.

People with active TB should be separated from others until they can no longer spread the disease. If you have TB or spend time around people with TB, wear a disposable face mask. Certain types of air filters can trap the TB bacteria, and ultraviolet light can kill it.

TB Symptoms

After TB bacteria are inhaled, they settle in the lungs. People with healthy immune systems can usually fight the bacteria and keep it from multiplying. The immune system may build structures that wall off the bacteria. These structures can burst, leaving scars in the lungs. If a person's immune system is too weak and the structures burst, the bacteria can get out and enter the bloodstream. Once in the bloodstream they travel to other parts of the body including the brain, kidneys, and bones. This is called "extrapulmonary TB." Extrapulmonary TB is more likely in people with advanced HIV disease.

People with active TB disease may develop symptoms including:

• Cough lasting more than 2-3 weeks
• Coughing up sputum (phlegm) or blood
• Unexplained weight loss
• Fever or chills
• Night sweats
• Fatigue (unusual tiredness)
• Loss of appetite
• Chest pain