Spread by droplet nuclei. Each droplet 1 bacillus.

1-5 microns in size. Need to be less than 10 microns to infect alveoli.

Can remain suspended in air for several hrs

1 cough=500 droplets

Infectiousness of person with TB

Environment in which exposure occures

duration of exposure

virulence of the organism

Unhealthy person

Bacilli overwhelm immune system

Bacillil break out in alveoli and spread through blood stream

Health person

initial infection controlled by immune system

bacilli remain confined in tubercles for years

lungs

pleura

CNS

lymphatic system

genitourinary system

Bones and joints

Disseminated (Miliary TB)

Primary resistance: develops in persons inititially infected with resistant organisms

Secondary resistance: Develops during TB therapy -poor adherence, inadequate treatment

TB class

 no hx of exposure, negative reaction to tuberculin skin test

Class 0

No TB exposure, not infected,

Classifying Tb

hx of exposure

negative reaction to TB skin test

Class 1

TB exposure

No evidence of infection

Classification

(+) reaction to TB skin test, negative bacteriologic studies, no clinical, bacteriological or radiograohic eviidence if active TB

Class 2

TB infection, no disease

Classification

M. tuberculosis culture, clinical, bacteriological, or radiographic evidence of current disease

Class 3

TB clinically active

Classification:

Hx of episodes of TB or abnormal but stable radiograohic findings, (+) skin test, negative bacteriological studies

no clinical or radiographic evidence of current disease

Class 4

Not clinically active Tb

Classification of tB

Diagnosis pending

Class 5

TB suspected

1. promptly identify persons with TB

2. Initiate appropriate treatment

3. Ensure completion of therapy

High risk exposure for TB

should be tested for LTBI

Close contact with infected persons

foreign-born persons from areas where TB is common

Residents and employess of high-risk congregate settinsg

Health care workers who serve high-risk clients

Medically underserved, low income. ethnic monority populations, drug users, and children exposed to adults in high-risk categories

Inject intradermally 0.1 ml of 5 TU PPD tuberculine

Produce wheel 6 mm to 10 mm in diameter

read reaction 48-72 hours after injection

Measure only induration-record in millimeters

no self measurement

HIV

 recently infected in last 2 years

persons with certain medical conditions

persons who inject illicit drugs

hx of inadequately treated TB

IGRA's IFN-y release assay

QFT-gold

single visit

blood draw vs. ID injection

less variation in interpretation

NO CROSS RXN WITH BCG (.99 specificity of BCG)

no boosting

limitations <17 and immunosupressed

Cost effectiveness in selected populations

Positive Tb skin test

immunosupressed

Travelers

No known RF

5 mm - in immunosupressed pts

10 mm - Travelers, drug users, exposed to high risk

15 mm - persons with no known risk factors

1. infection with non TB mycobacterium

2. previous BCG

3. Vaccination with live virus

4. PPD placed same day as live-virus vaccination or wait 4-6 weeks

Nontuberulous mycobacteria

BCG vaccine

Anergy-lack of immune response

recent TB infection

very young age

live-virus vaccine

overwhelming TB disease

Some people with LTBI may have negative skin test reaction when tested years after infection

Initial skin test may stimulate ability to react to tuberulin

-positive rxns to later tests may be misinterpreted as a new infection

Used for initial skin testing of adults who will be retested periodically -health care worker

1st + infected

1st - wait 1-3 wks later

2nd + infected

2nd - uninfected

med hx

physical examination

matoux/QFT

chest radiograph

bacteriologic or histologic exam-sputum

Productive, prolonged cough : duration of 3wks

chest pain

hemoptysis

fever

chills

night sweats

appetite loss

weight loss

easy fatigue

Back pain

Adenopathy++

Hematuria

Visual changes

Bone/joint pain

1. multidrug resistant

2. Resistant TB

3. Extreme Drug resistant TB

4. Coinfection

1. Examining persons who is not ill but may be infected

2. Determining how many people in group are infected

3. Examining person who has symptoms of TB

1.If pateint exposed to TB and ppd negative:

2. Think HIV

3. Length it takes after infection for infected person to develop an immune response to tubercullin

1. retest 10-12 wks after last exposure to infected person

2. 6 mo rule- can take 6 mo to show +

3. 2-10 wks

Abnormalities often seen in apical or posterior segments of upper lobe or superior segments of lower lobe

cavitations, cavities, infiltrates, calcified granulomas

-Cant confirm diagnosis of TB

Confirm Tb

Sputum collection and Smear examination

results in 4 to 14 days when liquid medium systems used

repeat for patients who:

-do not respond to therapy

-Have positive cultures despite 2 mo of therapy

-cont to do sputum until test is negative

9 mo regimen considered optimal: 270 doses

Children receive 9 mo of therapy

Can be given twice-weekly if directly observed

Adults: 300 mg qd

Children: 10-20 mg kg qd

1. baseline live funx if suggested liver dis or HIV infections, pregnany women immediate post-partum

2. monthly evauate for adherence to prescribed reginmen, signs of active TB, signs of hepatitis

3. ENSURE adherence!

1. Assign responsibilty

2. Systematic regular review

3. plans to address barriers to adherence

healthcare worker watches pt swallow each pill

-promote adherence

-prevents relapse

Isoniazide

rifamprin

pyrazinamide

ethambutol (EMB) or streotomycin

Takes longer than Pulm Tb

Treat for a minimum of 12 mo

pt coughing

undergoing cough-producinig procedures

have + sputum smears

are on therapy- or started

have poor clinical response to therapy

-On adequate therapy

-Have significant response to therapy

-have had 3 consecutive negative sputum smear results

Cont exposure to untreated/ineffectively treated infected person

Exposed to multidrug resistant TB

Place where high % of MDR pts have been found

Tuberculine skin testing no CI for BCG vaccinated persons