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Clin Med exam 3
TB
49
Medical
Graduate
10/30/2010

Additional Medical Flashcards

 


 

Cards

Term
Transmission of TB
Definition

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

Term
The probability of TB being transmitted is based on:
Definition

Infectiousness of person with TB

 

Environment in which exposure occures

 

duration of exposure

 

virulence of the organism

Term
probability of becoming infected with TB if you spent 24 hours a day for 2 mo with someone with active disease
Definition
50%
Term
Chances of becoming infected spending 8 hours for 6 mo with someone infected:
Definition
50%
Term
What percent of infected persons with normal immune systems develop TB at some point of their life:
Definition
10%
Term
What is the strongest risk factor for developing TB if infected
Definition
HIV
Term
Risk of developing TB disease with HIV:
Definition
inc 7% to 10% each year with HIV
Term
Active infection
Definition

Unhealthy person

Bacilli overwhelm immune system

Bacillil break out in alveoli and spread through blood stream

 

 

Term
Latent TB
Definition

Health person

initial infection controlled by immune system

bacilli remain confined in tubercles for years

Term
Common sites of TB disease
Definition

lungs

pleura

CNS

lymphatic system

genitourinary system

Bones and joints

Disseminated (Miliary TB)

Term
Two types of drug resistance and definitions:
Definition

Primary resistance: develops in persons inititially infected with resistant organisms

 

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

Term

TB class

 no hx of exposure, negative reaction to tuberculin skin test

Definition

Class 0

 

No TB exposure, not infected,

Term

Classifying Tb

 

hx of exposure

negative reaction to TB skin test

Definition

Class 1

 

TB exposure

No evidence of infection

Term

Classification

 

 

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

Definition

Class 2

TB infection, no disease

Term

Classification

 

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

Definition

Class 3

 

TB clinically active

Term

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

Definition

Class 4

Not clinically active Tb

Term

Classification of tB

Diagnosis pending

Definition

Class 5

 

TB suspected

Term
3 ways to strengthen TB control:
Definition

1. promptly identify persons with TB

 

2. Initiate appropriate treatment

 

3. Ensure completion of therapy

Term

High risk exposure for TB

should be tested for LTBI

Definition

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

 

Term
Administering the Tuberculin skin test
Definition

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

Term
High risk for developing TB once infected
Definition

HIV

 recently infected in last 2 years

persons with certain medical conditions

persons who inject illicit drugs

hx of inadequately treated TB

Term

IGRA's IFN-y release assay

 

QFT-gold

Definition

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

 

Term

Positive Tb skin test

 

immunosupressed

 

Travelers

 

No known RF

 

Definition

5 mm - in immunosupressed pts

 

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

 

15 mm - persons with no known risk factors

Term
Other reasons a skin test would show positive
Definition

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

Term
False positive cause:
Definition

Nontuberulous mycobacteria

BCG vaccine

Term
Falso negative cause
Definition

Anergy-lack of immune response

recent TB infection

very young age

live-virus vaccine

overwhelming TB disease

Term

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

Definition
Boosting
Term

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

Definition
Two-step testing
Term
Evaluation for TB
Definition

med hx

physical examination

matoux/QFT

chest radiograph

bacteriologic or histologic exam-sputum

Term
Symptoms of pulmonary TB
Definition

Productive, prolonged cough : duration of 3wks

 

chest pain

 

hemoptysis

Term
Systemic symptoms of Tb
Definition

fever

chills

night sweats

appetite loss

weight loss

easy fatigue

Term
Extra pulmonary symptoms
Definition

Back pain

Adenopathy++

Hematuria

Visual changes

Bone/joint pain

Term
Other TB complications
Definition

1. multidrug resistant

2. Resistant TB

3. Extreme Drug resistant TB

4. Coinfection

Term
Tuberculin skin testing useful for:
Definition

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

Term

 

 

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

 

Definition

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

 

Term
Chest XRAY results:
Definition

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

Term
Cultures:
Definition

Confirm Tb

Sputum collection and Smear examination

 

results in 4 to 14 days when liquid medium systems used

Term
Drug susceptibility testing
Definition

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

 

 

Term
TX of LTBI with isonizid
Definition

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

Term
Monitoring pts:
Definition

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!

Term
Case management:
Definition

1. Assign responsibilty

2. Systematic regular review

3. plans to address barriers to adherence

Term

healthcare worker watches pt swallow each pill

-promote adherence

-prevents relapse

 

Definition
Directly observed therpy (DOT)
Term
Include 4 drugs in initial regimen
Definition

Isoniazide

rifamprin

pyrazinamide

ethambutol (EMB) or streotomycin

Term
Extrapulm TB TX:
Definition

Takes longer than Pulm Tb

 

Treat for a minimum of 12 mo

Term
Considered infectious when:
Definition

pt coughing

undergoing cough-producinig procedures

have + sputum smears

are on therapy- or started

have poor clinical response to therapy

Term
Patients are NO longer considered infectious when:
Definition

-On adequate therapy

-Have significant response to therapy

-have had 3 consecutive negative sputum smear results

Term
BCG vaccine
Definition

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

 

 

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