Public Health Week #5

Front 1

Transmission of M. tuberculosis

Back 1

1. Spread by droplet nuclei
2. Expelled when person with infectious TB coughs,
sneezes, speaks, or sings
3. Close contacts are at highest risk of becoming infected
4. Transmission occurs from person with infectious TB disease (not latent TB infection)

Front 2

Probability TB Will Be Transmitted

Back 2

Infectiousness of person with TB
Environment in which exposure occurred
Duration of exposure
Virulence of the organism

Front 3

Pathogenesis

Back 3

-10% of infected persons with normal immune systems develop TB at some point in life
-HIV strongest risk factor for development of TB if Infected
-Risk of developing TB disease increases7% to 10% each year in people infected with HIV
-Certain medical conditions increase risk that TBinfection will progress to TB disease

Front 4

Conditions That Increase the Risk of
Progression to TB Disease

Back 4

1. HIV infection
2. Substance abuse
3. Recent TB infection
4. Chest radiograph findings suggestive of previous TB
5. Diabetes mellitus
6. End-stage renal disease
7. Prolonged corticosteriod therapy
8. Other immunosuppressive therapy

Front 5

Common Sites of TB Disease

Back 5

-Lungs
-Pleura
-Central nervous system
-Lymphatic system
-Genitourinary systems
-Bones and joints
-Disseminated (miliary TB)

Front 6

Drug-Resistant TB

Back 6

-Drug-resistant TB is transmitted same way as drug-susceptible TB
-Drug resistance is divided into two types:
a. Primary resistance develops in persons initially infected with resistant organisms
b. Secondary resistance (acquired resistance) develops during TB therapy

Front 7

Factors Contributing to the Increase
in TB Morbidity: 1985-1992

Back 7

Deterioration of the TB public health infrastructure
HIV/AIDS epidemic
Immigration from countries where TB is common
Transmission of TB in congregate setting

Front 8

Factors Contributing to the Decrease in
TB Morbidity Since 1993

Back 8

-Increased efforts to strengthen TB control programs that promptly identify persons with TB
-Initiate appropriate treatment
-Ensure completion of therapy

Front 9

Persons at Higher Risk for Exposure
to or Infection with TB

Back 9

-Close contacts of person known or suspected to have TB
-Foreign-born persons from areas where TB is common
-Residents and employees of high-risk congregate settings
-Health care workers (HCWs) who serve high-risk clients

Front 10

Persons at Higher Risk for Exposure
to or Infection with TB (cont.)

Back 10

-Medically underserved, low-income populations
-Children exposed to adults in high-risk categories
-Persons who inject illicit drugs

Front 11

Persons at Higher Risk of Developing
TB Disease once Infected

Back 11

-HIV infected
-Recently infected
-Persons with certain medical conditions
-Persons who inject illicit drugs
-History of inadequately treated TB

Front 12

Purpose of Targeted Testing

Back 12

-Find persons with LTBI who would benefit from treatment
-Find persons with TB disease who would benefit from treatment
-Groups that are not high risk for TB should not be tested routinely

Front 13

Groups That Should Be Tested for LTBI
Persons at higher risk for exposure to or infection with TB

Back 13

-Close contacts of a person known or suspected to have TB
-Foreign-born persons from areas where TB is common
-Residents and employees of high-risk congregate settings
-Health care workers (HCWs) who serve high-risk clients

Front 14

Groups That Should Be Tested
for LTBI (cont.):
Persons at higher risk for exposure to or infection with TB

Back 14

-Medically underserved, low-income populations
-Children exposed to adults in high-risk categories
-Persons who inject illicit drugs

Front 15

Groups That Should Be Tested
for LTBI (Cont.):
Persons at higher risk for TB disease once infected

Back 15

-Persons with HIV infection
-Persons recently infected with M. tuberculosis
-Persons with certain medical conditions
-Persons who inject illicit drugs

Persons with a history of inadequately treated TB

Front 16

Administering the Tuberculin Skin Test

Back 16

-Inject intradermally 0.1 ml of 5 TU PPD tuberculin
-Produce wheal 6 mm to 10 mm in diameter
-Do not recap, bend, or break needles, or remove needles from syringes

Follow universal precautions for infection control

Front 17

Reading the Tuberculin Skin Test

Back 17

-Read reaction 48-72 hours after injection
-Measure only induration
-Record reaction in millimeters

Front 18

Classifying the Tuberculin Reaction:
Less than or = to 5 mm is classified as positive in.....:

Back 18

-HIV-positive persons
-Recent contacts of TB case
-Persons with fibrotic changes on chest radiograph consistent with old healed TB
-Patients with organ transplants and other immunosuppressed patients

Front 19

Classifying the Tuberculin
Reaction (cont.):
Less than or = to 10 mm is classified as positive in...:

Back 19

-Persons with no known risk factors for TB
-Targeted skin testing programs should only be conducted among high-risk groups

Front 20

Classification System for TB:
Class 0

Back 20

-No TB exposure
-Not infected
-No history of exposure
-Negative reaction to tuberculin skin test

Front 21

Classification System for TB:
Class 1

Back 21

TB exposure
No evidence of infection
History of exposure
Negative reaction to tuberculin skin test

Front 22

Classification System for TB:
Class 2

Back 22

-TB infection
-No disease
-Positive reaction to tuberculin skin test
-Negative bacteriologic studies (if done)
-No clinical, bacteriological, or radiographic evidence of active TB

Front 23

Classification System for TB:
Class 3

Back 23

TB, clinically active
M. tuberculosis cultured (if done)
Clinical, bacteriological, or radiographic
evidence of current disease

Front 24

Classification System for TB:
Class 4

Back 24

TB
Not clinically active
-History of episode(s) of TB or abnormal but stable radiographic findings
-Positive reaction to the tuberculin skin test
-Negative bacteriologic studies (if done)
-No clinical or radiographic evidence of current disease

Front 25

Classification System for TB:
Class 5

Back 25

TB suspected
Diagnosis pending

Front 26

Factors that May Affect the Skin Test Reaction:
False-positive

Back 26

possible causes for that:
Nontuberculous mycobacteria BCG vaccination

Front 27

Factors that May Affect the Skin Test Reaction:
False-negative

Back 27

possible cause:
1.Recent TB infection
2. Very young age (< 6 months old)
3. Overwhelming TB disease

Front 28

Use two-step testing for initial skin testing of adults who will be retested periodically:
If first test positive....

Back 28

consider the person infected

Front 29

Use two-step testing for initial skin testing of adults who will be retested periodically:
If first test negative...

Back 29

give second test 1-3 weeks later

Front 30

source vs. casefinding TB cases

Back 30

source finding is for children with postive ppd test or younger. We are looking for the source.

Front 31

Use two-step testing for initial skin testing of adults who will be retested periodically:
If second test positive....

Back 31

consider person infected

Front 32

Use two-step testing for initial skin testing of adults who will be retested periodically:
If second test negative...

Back 32

consider person uninfected

Front 33

Classifying the Tuberculin Reaction (cont.):
Less than or equal to 10 mm is classified as positive in...

Back 33

-Recent arrivals from high-prevalence countries
-Injection drug users
-Residents and employees of high-risk congregate settings
-Mycobacteriology laboratory personnel
-Persons with clinical conditions that place them at high risk
-Children <4 years of age, or children and adolescents exposed to adults in high-risk categories

Front 34

Evaluation for TB

Back 34

Medical history
Physical examination
Mantoux tuberculin skin test
Chest radiograph
Bacteriologic or histologic exam

Front 35

Symptoms of Pulmonary TB

Back 35

-Productive, prolonged cough
(duration of greater than or = 3 weeks)
-Chest pain
-Hemoptysis

Front 36

Systemic Symptoms of TB

Back 36

Fever
Chills
Night sweats
Appetite loss
Weight loss
Easy fatigability