TB Flashcards
progression to lung pneumonitis
- inhaled
- macrophages eat–> blood
- lung pneumonitis, lymph nodes, etc
what makes it “latent” TB
lung pneumonitis gets resolved
list 3 things that can activate LTBI
pregnancy
HIV or DM
taking immunomodulators
how is TST read? (3)
measure induration perpendicular to long axis
ignore redness
record in mm
induration cut off for high pretest probability vs middle vs very low
- high: 5mm
- middle: 10
- very low: 15
examples of people w/ high pretest probability (4)
- ppl w/ HIV
- close contacts
- immunocompromised/using steroids
- fibrotic change on CXR/ old TB
examples of people w/ “mid” pre-test prob (5)
- healthcare workers or long term facility ppl
- recent immigrants
- injection drugs
- younger exposed to high risk adults
- underlying illness
Having these conditions can cause false ____ with TST
general illness, steroids, immunosuppression, long duration since infection, malnutrition
false negative
Having these conditions can cause false ____ with TST
nontuberculous mycobacteria
false positive
list some P.E. findings with TB (5)
- dullness to percussion
- rales
- tubular breath sounds
- whispered pectoriloquy
- distant hollow/amphoric breath sounds
6 radiographic findings
- infiltrates in upper lobes
- Cavity formation esp at the apical area
- Hilar adenopathy
- Atelectasis
- Pleural effusion
- Miliary TB
list 5 extrapulmonary findings w/ TB seen more in kids
- meningitis
- osteomyelitis
- GI issues
- renal issues or GU tract
- scrofula– isolated infected neck node
4 diagnostic tests/procedures used for TB
- TST
- IGRA
- sputum smear
- culture
media used to culture TB
AFP culture on jensen media
when do you get sputum smear?
(+) PPD or IGRA
AND
abnormal CXR
Whole blood assay that measures immune response to M. TB antigens
IGRA
which test shows no response to non-TB mycobacteria or BCG
IGRA
4 limitations of IGRA
- LTBI has no gold standard
- not standard
- may be falsely negative in active dz
- not reliable for kids under 5
3 situations where we use IGRA
- at risk over 5yo
- confirm positive TST in BCG
- confirm TST when non-TB mycobacteria suspected
if patient has negative TST, negative IGR but you think they might have TB, can you r/o TB?
no, investigate more
list the first line agents (5)
Isoniazid (INH), Rifampin (RIF), Pyrazinamide (PZA), Ethambutol (EMB), Streptomycin (STM)
can you treat close contacts?
yes w/ prophylactic abx
medication regimen in first 2 months of tx of active TB
INH + RIF + PZA + (EMB* or STM*)
drop last two after confirming susceptibility
medication regimen for last 4 months for active TB
INH + RIF
