Tuberculosis (TB) - The Unseen Villain

Julie Reyes, DNP, RN

TB - what is it?

Mycobacterium tuberculosis (M. tuberculosis - or TB) is an airborne disease carried in airborne particles (droplet nuclei 1-5 microns in diameter). Inhalation of the TB droplet can develop into the lungs - in most cases - but can affect any part of the body. Infection in the lungs is called pulmonary infection, and outside of the lungs is called extrapulmonary infections. Extrapulmonary tuberculosis can be found any other organ systems such as the kidneys, heart, or brain - as well as in joints or in bones.

Types of TB

Not everyone infected with TB bacteria becomes sick. As a result, two TB-related conditions exist: latent TB infection and TB disease.

Latent TB (LTB) means a person does have TB in their body but does not have TB disease and cannot spread the disease to other people. If a person is healthy or not immunocompromised, their immune system may be able to stop the TB from multiplying and prevent progression of the disease. If left untreated, LTB can turn into TB disease.

TB Disease (TBD) happens when the body is unable to halt the disease progression. The person may progress from LTB to TBD immediately after exposure to many years after exposure.

TB - what are the signs and symptoms?

a bad cough that lasts 3 weeks or longer
pain in the chest
coughing up blood or sputum
weakness or fatigue
weight loss
no appetite
chills
fever
sweating at night

You may also see a signs/symptoms of synovitis, pericarditis, meningitis, cervical lymphadenitis, pleuritis, or infections of the bones, joints and/or skin (such as an abscess).

TB - how is it spread?

Droplets can "float" in the air almost indefinitely due to its small size and virtual weightlessness, and can be carried on normal air currents (Biological Controls, 2015). Droplets not only can come from an infected person's cough, but can also come from an infected abscess when opened and the particles become airborne, for example. This may seem like a no-brainer, but the closer the proximity a person is to an infected TB patient, the more droplet nuclei in the air, the more exposure a person has, and the longer duration of exposure will increase the risk for transmission.

TB Incubation Period

A person who is suspected of coming into contact with TB should be tested. The recommended testing period is 8-10 weeks after exposure - after the incubation period. It can take 2-8 weeks for a person to test positive for TB with a skin test or IGRA.

TB programs - What is your facility doing to protect you?

TB mask fitting

OSHA requires healthcare facilities to provide mask fit testing annually for healthcare workers who may come into contact with TB. This includes (but is not limited to) nurses, therapists, environmental services, clergy, lab employees, maintenance workers, and doctors. Your facility will fit test you to a NIOSH mask that will provide you protection from inhaling in the tiny TB droplets than can pass through regular face masks. There are several types of masks that are available and approved by OSHA. The mask must make a tight seal over the nose and mouth and under the jaw to provide protection. People with facial hair will not be able to get a tight seal and a NIOSH mask will not be effective for them.

Additionally, OSHA requires a yearly questionnaire to be completed and kept on record every year as well. Unfortunately, this questionnaire must record the weight of the employee. WHY? The employee should be fit tested again if there is a 5% change in body weight as this can change the facial features and the mask that once fit may no longer be adequate. Other reasons to have a fit testing redone include reconstructive facial surgery or dental work affecting facial features.

TB testing

There are a few different tests that are available to test for TB. Many healthcare facilities continue to use a TB skin test (TST). While the CDC approves of this method, there are other tests available which are more accurate and can eliminate false negatives or false positives. Interferon-gamma release assay's (IGRA) are an example of this type of test (you may have heard of QFT or Tspot). This is a simple blood test that does not require fasting. A chest x-ray may be ordered to look for cavitations in the lungs.

TB exposure at work - what to do?

An exposure at work would be followed closely by the Occupational Health and Infectious Disease departments. Occupational Health will have the responsibility of tracking down and informing all employees who have been or may have been involved in an exposure and guide them on the exposure process. This will include a TST or IGRA in 8-10 weeks after the exposure, providing signs/symptom information, and referring any positive results to the health department or to the employee's primary care provider.

Resources

CDC Tuberculosis (TB) Data and Statistics

CDC | TB | Fact Sheets - Tuberculosis: General Information

Biological Controls Inc.

Transmission and Pathogenesis of Tuberculosis (PDF)

CDC | TB | TB Education and Training Resources