TB Flashcards
Characteristics of mycobacterium Tb
acid fast rod aerobic slow growing intracellular
special stain for mycobacterium Tb
Ziehl Neilsen stain
when do you see mycobacterium avium
in AIDS patients when CD4 count drops below 50
Explain the path of infection of Tb
Tb is inhaled
implants in alveoli and is taken up by macrophages where it grows slowly
what happens when the macrophage infected with Tb dies
lymphohematogenous spread
What is a Gohn Complex, where is it located
Gohn complex is a calcified granuloma that occurs in a primary Tb infection.
Often located in the lower lobes.
what are te signs on CXR of a primary infection
Gohn Complex
hilar LAD
What is a Simon Foci
Graunloma in the apical and posterior part of the lungs that is the result of Tb spreading to the lungs from another organ.
Site of secondary reactivation
What are the potential outcomes of a primary pulmonary Tb infection
Host wins, time bomb, host loses
what happens if the host wins
Tb is sucesffully contained in a granuloma with little or no caseastion, and the calcification may be seen on CXR
what happens in the case of a time bomb
there is a 10% risk of reactivation, this lesion has caseation with dormant Tb.
what happens if the host loses
hematogenous spread called miliary Tb, it can spread to CNS, LN, GI, and kidney
what is Pott’s disease
When Tb spreads to the SC
what is reactivation? what is is normally preceded by, what normally reactivates
Reactivation is when a site of infection reactivates and starts to spread
this is normally preceded by a decrease in immune function.
Foci that often reactivate are apical or extrapulmonary
Pulmonary signs of a Tb infection
Rales
Consolidation
chest asymetry
Non pulmonary signs of a Tb infection
Hepato/splenomegaly
LAD
Symptoms of a Tb infection
weight loss, night sweats, hemoptysis
Fatigue, chills, myalgia, productive cough, and chest pain
Diagnosis of Tb- culture and staining
staining of Tb with Ziehl Neilsen stain after being grown on Lowenstein Johnson medium
what body fluids will contain Tb
gastric lavage, lung biopsy- PCR
mantoux ppD test
Type IV hypersensitiviy rxn
immunocompromised or pts that have a previous Tb incfection anything over 5 mm is +
at risk populations- anything over 10 mm is positive
general population- anything over 15 mm is positive
Tb tx
isoniazid
Rifampicin
emthambutol
pyrazinamide
when are you no longer infectious
must meet all 3
2-3 weeks of tx
a positive response to tx
3 consecutive negative sputum smears
