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Flashcards in TB Deck (34):
1

What is the pathogenesis of a TB infection?

1. inhaled bacilli are ingested by macrophages
2. bacilli replicate within macrophage, kill it, and spread hematogenously upon release

2

How is a TB infection contained by a normal immune system?

via cell-mediated macrophage and lymphocyte response; granulomas develop in involved tissues and wall off persistent mycobacterium

3

Reactivation TB occurs if:

immunity wanes in future (after granuloma formation) due to HIV, infection, steroids, immunosuppressants, cancer, etc

4

Persons likely to have been infected recently:
("external")

-close contact
-tuberculin conversion within 2 yrs
-new immigrants from areas of high TB prev
-residents/employees of prisons, NH, etc
-exposed health care workers
-HIV (+)
-IV drug users
-kids exposed to high-risk adults

5

Who should be screened for TB?

Persons likely to have been infected recently

Persons in conditions that increase risk of progression from latent to disease state

6

Medical Conditions of High Risk for TB

-Diabetes mellitus
-Silicosis (*destroys macroph)
-Prolonged corticosteriod therapy
-Other immunosuppressive therapy
-Cancer of the head and neck
-Lymphomas and Leukemias
-Organ transplant recepient
-End-stage renal disease
-Intestinal bypass or gastrectomy
-Chronic malabsorption syndromes
-Low body weight: >10% below the ideal

7

Pulmonary TB symptoms

cough
fever
night sweats
weight loss
hemoptysis

8

Pulmonary signs of TB

Cachexia
Signs of consolidation
Rales: crackles
Advanced: respiratory failure

9

Extra-pulm signs of TB

Renal- pyurea
Meningeal- fever, neck stiffness, coma
Bony- Potts Disease, neuropathies
Scrofula- cervical lymphadenitis (WTF did I misspell?)

(EXTRa PuLM = extremities (bony/neuropathy), pyurea, lymphadenitis, meningitis)

10

In (+) IGRA test, T cells of individuals infected with MTB produce ____ when exposed to...

interferon-gamma

the MTB antigen

11

What is a strength of IGRA testing?

more sensitive than TST
more specific than TST
do not have to return to clinic to get results

12

What tests can be used for detecting latent tuberculosis infection?

TST or the interferon-gamma release assay

13

In USA, most reported cases of TB have:

abnormal chest radiograph

14

What 2 signs are more common in primary TB?

Adenopathy and pleural effusion

15

What is more common in reactivation TB?

Apical disease and cavities

16

What can be seen with both reactivation and primary TB? What does this signify?

Miliary TB
ICH

17

The gold standard of TB diagnosis:

culture-isolation of MTB with sputum (preferably spontaneously expectorated)

18

The five commandments of diagnosis of
Tuberculosis:

Suspect the disease from demographics
Culture appropriate specimens
Obtain Chest X-ray
PPD skin test
Examine (symptoms and signs)

=SCOPE

19

1st line TB drugs (6)

1. Isoniazide
2. Rifampin
3. Pyrazinamide
4. Ethambutol
5. Rifabutin
6. Rifapentine

("RIPE")

20

2nd line TB drugs

1. Amikacin
2. Kanamycin
3. Capreomycin
4. Ethionamide
5. Fluoroquinolones

21

Patients are no longer considered infectious
if...

On adequate therapy with multiple agents.

Had a significant clinical response to therapy.

Had 3 consecutive negative sputum smears.

22

After TB exposure, ____% will have a positive skin test. Of these, ___% will actually develop disease, but only if...

25%
10%
immunosuppressed

23

During the first ___ years after infection, people are at a high risk of developing TB.

2

24

The containment of TB in the body is the function of:

macrophages and lymphocytes

25

When does tuberculin conversion occur? When will a skin test be (+)?

6-10 weeks after infection
2 weeks after exposure

26

Where will TB likely spread in the body?

bone
brain
lungs
kidneys

27

The incidence of TB in the US is (increasing/decreasing)

decreasing

28

The current goal of TB screening is to identify:

those at high risk of developing TB from a latent infection

29

What is the greatest known risk factor for reactivation of latent TB?

HIV

(10% risk per year of developing TB if hx of (+) skin test; 40% co-infection rate in inner city clinics)

30

Symptoms of pulmonary tuberculosis are:

nonspecific
pulmonary
systemic

31

Preventive therapy for TB is mainly targeted to...

secondary prevention (infected but latent)

32

Acceptable regimens for latent TB infections (3):

INH daily or twice weekly x9mo
INH daily or twice weekly x6mo
Rifampin daily x4mo

33

T/F: If a drug is failing in TB trx, add another abx.

F! bad for resistance

34

Regiments for active TB infections:

PZA or EB x2mo
INH or RM x6mo

(is this right? I was confused)