TB Flashcards
what are the top five countries with TB?
Ethiopia, India, Viet Nam, the Philippines, and El Salvador
How is TB transmitted? **
transmitted through Inhaled airborne droplets containing viable organisms
(ppl w active disease, talks coughs, sneezes)
how does the immune system react when TB first comes into the body?
lymph nodes wall it off, creating caseating granulomas and calcified areas (long term inflammation)
what does “caseating” look like? what is this appearance suggestive of?
cheesy material in middle suggesting destruction
of tissue on pathology
___% of people will not be successful at “walling off” the TB. it will go from primary TB to become ___________TB
5%; PROGRESSIVE PRIMARY
___% of people have latent TB after primary. What is latent TB?
95%; wall off bacilli and don’t get active infection
____% of latent TB pts will have reactivated TB
10% (pt has had TB for >2 yrs)
what populations are at risk for TB?
poorer populations, less developed countries, homeless, those on dialysis (for some reason… dont know why). etc.
calcified TB in lungs can be seen with what kind of imaging?
Chest Xray
primary TB presents how?
usually clinically silent with normal CXR
Calcified granuloma is called _______
Calcified granuloma and calcified hilar lymph node is called ____________. which of these is the more common one?
Calcified granuloma called Ghon complex (common)
Calcified granuloma and calcified hilar lymph node termed Ranke complex (not commonly seen)
what is the time period requirement between latent and reactivation?
Reactivation:
had TB for > 2 years, was latent and now active again
Clinical presentation: 3 symptom types for TB. which is the most common
pulmonary (most common), extrapulmonary and disseminated
clinical presentation- pulmonary: where is it found and what are the two characteristic presentations?
-likes O2, so its found in upper lobes
Primary or latent TB: asymptomatic
Reactivated or progressive primary: Slowly progressive malaise, anorexia, weight loss, fever, and drenching night sweats)
ALSO chronic cough: Dry, then productive then bloody
dyspnea is LATE symptom
extrapulmonary vs disseminated: where they are found and what are their clinical presentations?
Extrapulmonary: Spread through lymph or blood
Does not occur in primary – usually means reactivation TB
Disseminated (TB all throughout the body) in immunocomprimised
how does a pulmonary TB patient look on physical exam? what is the classic symptom?
Chronically ill and malnourished (b/c chronic infection is a huge metabolic demand)
Classic post-tussive rales: Crackles heard after cough (usually these are cleared with cough)
most common extrapulmonary presentation? what GU presentation? what is miliary TB?
lymphadenitis
GU TB – sterile pyuria (WBCs in urine from TB)
Miliary TB – Spread through other parts of lung through blood and not direct extension. looks like little yellow seeds or a shot-gun pattern
____ Dx is key for TB
Early diagnosis key
what is considered to make someone a high index of suspicion for TB?
bloody cough
Chest Xray for primary progressive TB will show what?
- homogenous infiltrates
- hilar and paratracheal lymph node enlargements
- segmental atelectasis
Chest Xray for reactivation TB shows what?
-Fibrocavitary apical dz
posterior segment of upper lobes or superior segments of lower lobes (O2 highest here)
what are cavitations?
looks like walled off bubbles in primary progressive and reactivation TB
how do you take cultures for TB?
Three early a.m. sputums, gastric aspiration (sputum swallowed during night) or bronchial washings
Positive culture takes_________ to grow and get sensitivity
6-8wks (very slow growing)
how do you Dx TB?
culture (three early am sputums most likely)
what is the prevention for primary TB? what type of vaccine is this?
BCG vaccine (not used in the US tho)
PPD Measures what type of hypersensitivity ?
delayed- cell mediated (type IV)
PPD tests Identifies those _______ _______ but does not tell if _______ or _______
likely infected, but does not tell if active or latent
how do you tell if a PPD is positive? how long does it take for someone to show positive result after infection?
by induration (not just erythema) 2-12 weeks.
5mm PPD is positive for what populations? (4)
1) . HIV-positive persons
2) . Recent contacts of TB case
3) . Persons with fibrotic changes on CXR chest radiograph consistent with old healed TB
4) . immunosuppressed patients
10mm PPD is positive in what populations? (7)
1). Recent arrivals from high-prevalence countries
2). Injection drug users
3). Healthcare workers
4). Mycobacteriology laboratory personnel
5). Persons with clinical conditions that place them at high risk
6). Children < 4 years of age, or children and adolescents
exposed to adults in high-risk categories
7). Recent converters (those with an increase of 10 mm or more in size of TST reaction within a 2-year period)
15mm is positive for PPD in what populations?
everyone else!
what is a “recent converter” when we talk about TB patients?
people whose past PPD tests were negative but then had a positive result
why do a 2 step PPD?
2 step PPD to be sure that a first negative response is not due to a waning immune response in someone infected long ago
2 step PPD, if the first test is negative, check ____ week(s) later, and what if the second is … positive? negative?
If the first one is negative, check a second one a week later; if second one is:
POS, then Pt was previously exposed, and response was enhanced from the boost
NEG, then Pt is very anergic or not exposed
Quantiferon Gold measures what?
it is a blood test that measures patient’s immune reactivity to TB bacterium
what is the only thing that can definitively Dx TB?
culture
do we treat TB if theres no definitive Dx but there is a high suspicion?
YES!
what is the best place to find the newest treatment goals for TB?
CDC - the latest is 2016
principle of TB txt : administer ____ drugs for ____ to _____months.
Administer multiple, susceptible drugs, generally for 6-9 mo
how do you ensure adherence to TB treatment? why is this important?
DOT – Directly observed therapy, decrease MDR-TB (Multi drug resistance)
what is the general treatment regiment for those with high index of suspicion of TB?
you start them on 4 drug cocktail for 8weeks on meds then get culture then change to fewer, more specific drugs (more specific drugs based on the sensitivity and specificity). (6-9mmonths after that)
if there is multi-drug resistance for TB? what do you do?
consult an ID expert!
how is treatment different for HIV positive TB patients?
need longer therapy regiment b/c the immune system doesnt work well
Also, still use DOT and ID.
Treatment monitoring to TB: patients need what to be deemed “no longer infective”? How frequent are checkups following this? What if they are at risk?
3 negative a.m. sputums
See monthly, if at risk, check hepatic panel for drug toxicity
what ADRs are you worried about with TB treatment?
toxicities - liver and neuropathy
complications with TB txt: destruction of the lung in TB is from _______ _______ and not ________ .
Destruction of lung is from immune reaction and not bacilli.
what patient education is important for TB treatment?
Noncompliance a major problem
Education increases compliance
Case manager helps improve compliance
DOT
mortality with DOT is < __% , what is the significance of this?
<5%, means drug therapy works if patients stick with it!
dont forget to report active TB to who?
Board of Health!
Positive PPD, no symptoms, normal CXR … what it the Dx?
latent TB
what do you consider when trying to decide whether to treat latent TB or not?
Balance risk of disease against risk of liver and nerve toxicity from treatment drugs
(younger patients are less likely to have ADRs from drugs so they are more likely to take treatment)
which drug is the shortest duration for TB and how long is this? what is another major benefit of it?
Isoniazid is shortest txt- 6 months and least likely to cause hepatotoxicity
characteristics of mycobacterium tuberculosus? (4)
rod shaped
outer waxy capsule
acid-fast bacilli
aerobe
what is primary TB?
AFB grows slowly in alveoli, usually CLINICALLY SILENT with normal CXR
**everyone starts with this TB
Ghon complex is in what stage of TB? what is it?
primary TB
calcified granuloma, commonly seen
what does quantiferon test distinguish between?
vaccine and TB infection
