Concept B: Tb

Front 1

What is TB caused by?

Back 1

-myobacterium tuberculosis (gram-positive, acid-fast bacillus)

Front 2

Where does TB occur?

Back 2

-lungs
-larynx
-kidneys
-bones
-adrenal glands
-lymph nodes
-meninges

Front 3

Where are the highest incidence rates of TB?

Back 3

-developing countries of Africa and Asia
-incidence of TB in the US are occurring in foreign born persons, and ethnic minorities

Front 4

How is TB spread?

Back 4

-spread from person to person via airborne droplets
-more commonly spread by repeated close contact with the infected person
-not highly infectious and requires close, frequent, or prolonged exposure
-cannot be spread by hands, books, glasses, or dishes

Front 5

Describe the pathophysiology:

Back 5

-once inhaled, the small nuclei lodge in the alveoli
-m. tuberculosis replicates slowly and spreads via lymphatic system
-after cellular immune system is activated, a characteristic granuloma is formed from alveolar macrophages; this contains the bacteria and prevents further replication
-at this point, the person has TB infx, which can be detected by using a mantoux test (2-10 weeks to develop a pos rxn)
-granuloma is usually not viable and usually remains contained and active dz may never occur (and cannot spread the infx)
-if immune defense mechanisms are not effective, control of organism is not contained, active primary disease results

Front 6

True or False:
TB infection occurs when the bacteria are inhaled but there is an effective immune response an the bacteria become inactive.

Back 6

-True

Front 7

True or False:
TB infection in a person who does not have the active TB disease is not considered a case of TB and is often referred to as latent TB infection.

Back 7

-True

Front 8

True or False:
TB disease is defined as active bacteria that multiply and cause clinically active disease.

Back 8

-True

Front 9

Describe s & s of TB:

Back 9

-early stages of TB, usually free of symptoms
-people with LTBI have a pos skin test by are asymptomatic
-active TB: fatigue, malaise, anorexia, unexplained wt loss, low-grade fevers, night sweats, dyspnea
-characteristic manifestations: cough that becomes frequent and produces white, frothy sputum
-hemoptysis is NOT common
-acute symptoms: high fever, chills, generalized flu-like symptoms, pleuritic pain, productive cough

Front 10

Describe the mantoux test:

Back 10

-best way to diagnose latent TB infx
-induration (not redness) at the injection site 48-72 hr
-positive test means the person has been exposed to TB and has developed antibodies (at least 2-12 weeks after initial exposure)
-after a pos test, no other mantoux tests should be performed (always will be positive)
-in immune compromised, induration less than or equal to 5 mm is considered pos

Front 11

True or False:
CXR is a way to make a positive diagnosis.

Back 11

-False; b/c other dx can mimic the x-ray appearance

Front 12

How is diagnosis of TB made?

Back 12

-requires initial testing involving microscopic examination of stain sputum smears for acid-fast bacilli, confirming tubercle bacilli
-3 consecutive sputum specimens collected on different days are obtained and sent for smear and culture
-can take up to 8 weeks
-collected from gastric washing, CSF, or fluid from an effusion or abscess
-rapid diagnostic test called QFT is available; it does not replace smears and cultures but offers a faster diagnosis (within hours)

Front 13

Describe treatment of TB:

Back 13

-generally outpatient
-drug therapy for active dz: managed aggressively; 6 month regimen; INH, rifampin, pyrazinamide (PZA), and ethambutol; liver values must be monitored

-drug therapy for LTBI: can be used to prevent infx from developing active dz (INH; SID for 6-9mth)

Front 14

Describe the BCG vaccine:

Back 14

-attenuated strain of mycobacterium bovis
-found to decrease incidence in infants and children but not in adults
-results in a positive reaction

Front 15

Those with a positive tuberculin skin test should have a CXR to assess for the presence of TB

Back 15

-blah