04/11/23 1

TB Terminology and the

Transmission of Tuberculosis

Alisha Blair

Nurse Consultant Heartland National TB Center

04/11/23 2

Objectives

Provide Overview of Basic Terms used in TB Prevention and Control

Provide Brief Overview of the Pathogenesis and Transmission of Tuberculosis

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Tuberculosis

TB or Tuberculosis is a communicable disease caused by Mycobacterium tuberculosis complex

M. tuberculosis, M.bovis, M. Africanum, M.Microtti,

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How to Determine if You are Infected with TB Bacteria?

TB Skin Test Liquid called to

tuberculin is injected underneath the skin on the lower area of arm PPD TST

TB Blood Test Blood Test that

measures the response to TB proteins when mixed with Blood QuantiFERON T-SPOT

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Interpreting Test Results

Positive TB skin test reaction TB Infection TB Disease MOTT

(Mycobacterium other than tuberculosis)

Positive TB Blood Test TB Infection TB Disease

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Active TB Disease vs.

Latent TB Infection

Active TB Disease TB Bacteria are multiplying

and attacking a part of the body( usually the lungs)

Latent TB Infection TB Bacteria are alive but

inactive in the body

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Active TB Disease

Active TB Disease TB Bacteria are multiplying and attacking a part of the

body( usually the lungs)

Symptoms Cough >3weeks Fever Night Sweats Chills Anorexia Hemoptysis

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Diagnostic Tests

Chest X- Ray A Chest x-ray is made by exposing film to x-rays that pass through

the chest1. May be abnormal

Sputum Phlegm coughed up from deep inside the lungs

1. Smear- Test to detect bacteria that resemble TB bacteria in Phlegm

2. Culture- Test that confirms TB bacteria in a sample of Phlegm

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Latent TB Infection

TB Bacteria are alive but inactive in the body

Positive PPD

Symptoms

Asymptomatic

Normal Chest X-ray ( Usually)

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Transmission of TB

Spread by airborne route via inhaled droplet

nuclei

Transmitted when an Infectious person

Coughs

Sings

Laughs

Talks

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Pathogenesis of TB

Droplet nuclei are inhaled and travel to the alveoli in the lungs where infection begins

Alveolar Macrophages ingest the majority of the TB bacteria Majority of the TB bacteria at this time are destroyed of inhibited Small amounts of bacteria multiply intracelluarly and are

released when the marcophages die

TB bacteria travels through the lymphatic system and then through the bloodstream

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Potential Sites of TB Disease

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Immune Response

Immune system response kills most of the TB bacteria

Granulomas Form (

TB Infection

Usually takes 2-10 weeks for +TST

Immune System responds to kill TB Bacteria

TB Bacteria Multiplication is halted preventing further

spread

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Latent TB Infection(LTBI)

TB Bacteria are alive but inactive in the body

Treament

Isoniazid (INH) Daily 9 Months

10% of TB Infected (LTBI) persons with normal immune

systems will develop TB at some point in life