Fouty- Latent TB infections Flashcards
acid fast bacilli (mycobacteria)
Robert ____ developed Tuberculin in 1890
Koch
_____ testing of cows and pasteurization of milk eliminated bovine transmission of TB
tuberculin
precipitated protein fraction from a single strain of human tubercle bacillus; purified and potent; non-sensitizing
PPD test
high strength PPD increases _____ positive rate
false
main symptoms of active TB
coughing and night sweats
if patient has a reaction to PPD test, what does it mean
they have been exposed to tuberculosis before
Tools required for chemoprophylaxis of TB
skin test
chest x-ray
meds
unable to control initial infection
controlled infection to some degree
what factors of TB bacilli contribute to primary infection
amount and how strong (virulence)
____ indicates they have activated adaptive immune response and have T cells that will react to the proteins in PPD
+ PPD
travels to tissue and lymph nodes and dissemination
continued replication in non active monocytes
onset of cell-mediated immunity and delayed type hypersensitivity
MTB
location of primary calcified foci
lower lobes
location of re-infection tuberculosis
upper lobes
cavitary TB location
upper and lower lobes
______ occurs while CMI/DTH controls initial infection
dissemination
____disease progresses while primary foci is controlled
distal
infection
logarithmic growth
cell mediated immune response
primary complex controlled (dormant)
bacillemia
active TB
TB alive but controlled (through granulomas)
dormant
what can cause reactivation of TB in patient
medications for Crohn’s, HIV, cancer (suppresses immune system)
breakdown of _____ due to decreased immune response and cavitary pulmonary TB in upper lobes forms
granulomas
cavitary TB (reactivation)
most common reactivation spot for TB
RUL
how to control TB
find infected patients and treat them and isolate them
HIV infected or at risk
close contacts of newly diagnosed tuberculosis
fibrotic lesions on CXR c/w old healed TB
what is considered + PPD test
> /= 5mm induration
what is considered a + PPD test
> /= 10 mm induration
low risk groups
what is considered a + PPD test
> /= 15 mm
_____ groups should not be skin tested
low risk groups
Does the skin test represent a true Tuberculosis Infection?
Infected without clinical symptoms and with negative cultures
latent disease
What is the risk of progressing to Tuberculosis Disease?
Infected with clinical symptoms with positive cultures
active disease
no treatment (low risk, <15 mm)
along with IBD and Rheumatoid arthritis; increase likelihood of what
increase likelihood that TB infection will become TB disease
2 things to consider when asking “does the skin test represent a true TB infection”
size of induration
risk of exposure
treatment (high risk due to exposure; >5 mm)
treat (high risk of exposure; >5 and 10 mm) she’s a recent converter
when is the risk of developing TB disease after infection with MTB the highest
within the first 2 years after infection
Highest TB outbreak ever reported in the world
Prevalence was so high everyone was infected
Bethel, Alaska
____ decreased progression to TB disease
Isoniazid (INH)
goal when there is a +PPD test:
decrease risk of developing TB disease
treatment (came from high prevalence country and >10 mm)
_____ have the same rate of progression to TB disease as that of their native country for the first 5 years
immigrants
high-risk _____ treated with chemoprophylaxis if in US less than 5 years
immigrants
treat (exposure and >10mm; but low risk of developing TB disease)
after 5 years, the TB disease rate of immigrants is similar to TB infected US citizens which is what
within 2 years
age with an increased risk for INH-induced hepatitis
50-64
risk of INH-induced hepatitis increases with _____ therapy
longer
Immigrants from high-risk countries treated if in US less than ____ years.
5
Immigrants from high-risk countries in US greater than _____ years are only treated if another risk is present
5
treat or not
treat
A lot of _____ in patients with previous TB infection went on to develop active TB even though they were culture negative at time you screened them
scarring
calcified granuloma (Ghon focus)
granuloma + ipsilateral calcified lymph node
Ranke Complex
RUL (treat)
treat patient with _____ lesions to decrease progression to TB disease
fibrotic
- no treatment
- treat
- treat
what to do if children have been exposed but PPD test is pending
treat until get results back
treat (regardless of BCG status)
Most non-infected people vaccinated with BCG are PPD ____
negative
attenuated but live strain of M.bovis
used to prevent TB disease in developing countries
BCG vaccine
used in the US
determines if person has been exposed to TB
measures ____ release from sensitized T cells in patient’s blood
IFNgamma (assay)
If the T cells have never seen TB antigens before they won’t release _____
IFNgamma
does a negative PPD or IFNgamma assay rule out TB
NO
goal of PPD and IFNgamma assay
to identify patients infected w/ mycobacterium tuberculosis
inhale it and itrs trouble from the beginning (active TB)
initial infection replicates and replicates
no granulomas, no control (no activation of adaptive immune response)
happens in children and immunocompromised patients
die 2 months later
primary disease
granulomas present but no active TB disease
latent TB infection
re-activation of TB due to immune system being repressed
TB disease
important test to determine if someone has TB
chest x-ray
don’t test low risk individuals unless what
they are going into high-risk environment
if TB infected (+PPD or IFNgamma), make sure they do not have TB disease (active disease) by
asking about sx’s
CXR
sputum
The worst thing you can do is treat a patient for TB Infection if they have _____
TB disease (active disease)
treat for TB infection
approved treatment regimens for TB infection
Isoniazid + Rifampin for 3 months
Don’t repeat ____ if they already have +PPD test
skin test
only do CXR if patient has what
symptoms
