Tuberculosis TB Education

Tuberculosis (TB)

TB facts and figures1

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Days

The average case of TB requires 180 days of medications, in addition to x-rays, labs, follow-ups and testing of contacts

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Cost of TB cases in US

Cases of TB cost the US $480 million in 2018

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Deaths

In the US, there were 515 TB deaths in 2017

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Cases

7 out of 10 TB cases in the US occur in non-US born persons

Latent tuberculosis infection (LTBI) vs. active TB disease

It is important to note the distinction between LTBI and active TB. The majority of people who are infected with LTBI will never develop active TB. However, there are many factors that can cause the disease to become active.

Smiling man in a plaid shirt and blazer
Hear Kahyr’s challenges after developing active disease

 Signs and symptoms2

TB bacteria are most commonly found in the lungs. They can, however, spread to other parts of the body, in which case the symptoms would be localized in those areas. LTBI has no symptoms. Common symptoms of TB disease in the lungs include:

  • A bad cough that lasts 3 weeks or longer
  • Pain in the chest
  • Coughing up blood or sputum (phlegm from deep inside the lungs)
  • Weakness or fatigue
  • Weight loss
  • Loss of appetite
  • Chills
  • Fever
  • Night sweats

Testing

There are two categories of commercially available tests to detect TB infection:

Tuberculin skin test (TST)3

The TST has been used to detect TB infection for over 100 years. It requires an intradermal injection of a small amount of purified protein derivative (PPD), a TB antigen, into the skin. In 48-72 hours, the resultant induration is measured.

Process:

  • Tuberculin is injected into the skin on the lower part of the arm
  • Subject returns 48 to 72 hours later to have their test “read” to determine whether there has been a reaction to the tuberculin

Limitations:

  • Limited sensitivity, especially in the immunocompromised, young and elderly
  • Poor specificity; caused by:
    • Prior bacille Calmette–Guérin (BCG) vaccination
    • Non-tuberculosis mycobacteria (NTM) infection
  • Requires 2 visits
    • Failure to return for second visit = no test result
  • Subjective result
    • Administration and interpretation steps are technique-dependent  

Interferon-gamma release assays (IGRAs)

Two IGRAs currently approved by the FDA for use as an aid in diagnosing TB are: the T-SPOT.TB test and the QuantiFERON®–TB Gold Plus test (QFT® -Plus). These tests each involve a blood draw, which is then processed by a lab.

tuberculosis (tb) healthcare icon

Treatment4

People with active TB disease must be treated and must take all of their medication exactly as directed. If they do not do this, the TB bacteria can become resistant to the drugs used to treat it. A typical course of treatment for active TB lasts from 6-9 months and can often include the following drugs:3

  • Isoniazid (INH)
  • Rifampin (RIF)
  • Ethambutol (EMB)
  • Pyrazinamide (PZA)

It is is important to remember that TB is contagious and can be spread by an infected person coughing. For this reason, TB treatment often involves a period of isolation.

Exposure5

Exposure to TB occurs when you have spent time with someone who is infected with active TB disease. The bacteria are spread through the air when a person who has active TB sneezes, coughs or speaks. If you think you have been exposed to active TB , you should immediately contact your doctor or the local public health department.

Risk factors6

Learning about TB and the risk factors for TB is important, as there are several different factors that can make a person susceptible to TB. However, these risk factors usually fall into two categories:

  1. Being in close contact with someone who has been recently infected with TB
  2. Having a medical condition that weakens the immune system

1. Close proximity6

The chances of a person getting infected with TB are higher for people that are in close contact with others who are infected. This includes:

  • Family and friends of a person with TB
  • People who come from areas of the world with high TB rates
  • People in groups with high rates of TB transmission – such as the homeless, injection drug users or a person with HIV
  • People who work or reside in a place where the people are at a high-risk for TB – such as hospitals, homeless shelters, correctional facilities or nursing homes

2. Weak immune system6

People who have a weak immune system are at a high-risk for developing active TB. These include:

  • Babies and young children
  • People with chronic diseases
  • People with HIV/AIDS
  • Organ transplant recipients
  • Cancer patients undergoing chemotherapy
  • People receiving certain specialized treatment for autoimmune diseases

Overall, 5-10% of people with latent TB who don’t receive treatment will develop active TB disease at some point in their lives.5