TB, Histo, Cocci Flashcards
How is TB transmitted?
Airborne droplet nuclei
Can you get TB from a homeless person coughing when they walk past you?
Not likely. Usually requires prolonged exposure, like someone you live with.
How long after TB exposure will the PPD skin test be positive?
6-8 weeks
A latent TB infection involves macrophages surrounding the tubercle bacilli and creating a barrier shell called a ________
Granuloma
What can cause latent TB to reactivate
An immunocompromised state
After exposure, how many peopel develop active disease?
5%
How many peopel with latent TB have a reactivation?
5%
Can a chest X ray confirm TB diagnosis?
No, need diagnostic microbiology
What is the number one killer of HIV patients?
TB
What are the symptoms of TB?
Fever
Cough (3 wks) may or may not be productive/bloody
Chest pain
VAGUE SYMPTOMS
What is the classic finding of TB on physical exam?
Posttussive Crackles
****
How do you inject the Mantoux tuberculin skin test?
Given in forearm intradermal*
Create wheal with 0.1 mL PPD
How long after injecting PPD do you read the TST?
48-72 hrs
When reading a TST, what do you measure?
Induration, not redness
If a patient comes in and says they were hanging out with someone with active TB one week ago, and they want to know if they caught it, should you do a TST?
No, becasue it wont be positive for 6-8 weeks following exposure
A TST skin test is considered positive at 5mm of induration for what 5 groups of peopel?
- HIV +
- Recent contacts of those with active TB
- Evidence of TB on CXR
- Immunosuppressed (Chronic steroids)
- Organ transplant patients
A TST test is considered positive at 10mm for what 7 groups of peopel?
- Recent immigrants from countries with lots of TB
- IV drug users
- Mycobacterial lab personnel
- Residents/employees of high risk settings (healthcare workers, inmates, correction officers etc)
- High risk medical conditions
- Children under 4
- Youth who are exposed to high risk adults
A TST skin test is considered positive at _____mm for anyone without risk factors for TB
15
Why do healthcare workers neeed a 2 step TB test for their initial test?
1st test: negative
2nd test 1-3 weeks later: positive, TB infection present (creates “boosted” response and is likely due to past exposure)
I have nooooooooo clue what this means
What is the name of the TB vaccine that may create false positive TSTs
BCG (bacillus Calmette-Guerin)
What is the name of the interferon Gamma Release Assays (Blood tests) for TB testing
QuantiFeron TB Gold
T-SPOT TB
When would be good situations to do the more expensive TB blood test instead of the skin test?
- concerns that patient won’t return for the reading
- received BCG vaccine
Will the TB blood test differentiate between active/latent TB
No
What will you see on CXR of primary active TB?
NORMAL**
OR
Hilar lymphadenopathy*****
Cavities
Miliary pattern**
Pleural effusions/infiltrates
Will a CXR tell you if the pt has active or latent TB
No
What are you likely to see on CXR of latent TB
Dense nodules or lesions with possible calcification
What will you see on CXR of someone with a reactivation of latent TB
Cavities
Infiltrates
Adenopathy
Where in the lung fields do TB abnormalities appear?
Apical/posterior upper lobes
Superior areas of lower lobe
What does a Ranke complex indicate?
Healed primary TB
What does a Ranke Complex consist of?
- Ghon Lesion(Focus): calcified granuloma (tuberuloma)
2. Calcified hilar lymph node
How much sputum do you need to get to do TB sputum tests?
3 specimens 8-24 hours apart
At least 1 in the morning
What are the 3 TB tests you can do on sputum?
Smear
Cytology
Culture
What does a sputum smear look for and how long does it take?
Looks for acid-fast bacilli
Easy and fast results
What kind of Cytology test is done on sputum to look for TB?
Nuclei Acid amplification test (NAA)
Takes 48 hours
What is the only thing that will CONFIRM a diagnosis of TB?
Sputum culture
***
Sputum smear and cytology will support your dx, but can’t confirm it
What should you do if the AFB and NAA sputum tests are positive, but you don’t have the sputum culture results back yet?
TB disease is presumed, Pt is quarantined, and treatment is initiated immediately
If the sputum culture comes back positive, what do you need to do next?
Drug susceptibility treatment
If you do a biopsy to confirm TB, what is the hallmark finding?
Necrotizing (Caseating) Granulomas
If the sputum culture comes back negative, but you really think they have TB, what should you do?
Start treatment anyways and “monitor response”
What is the Xpert MTB/RIF Assay?
Its the automated NAA test using disposable cartilages that checks for:
TB
Rifampin Resistance
How long does the XPert MTB/RIF Assay test take?
2 hours
Where is the patient when you are treating them for active TB?
Isolated in a negative pressure inpatient hospital room
Taking their meds under DIRECT OBSERVED TREATMENT
What are the 4 drugs you use to treat active TB
Rifampin
Isoniazid
Pyrazinamide
Ethambutol
What are the 2 side effects of Rifampin?
Orange secretions
Skin sensitivity
What are the side effects of Isoniazid?
Hepatotoxicity: must monitor LFTs
Peripheral neuropathy (Vit B6 helps)
Fatal hepatitis (pregnant women at high risk)
What are the side effects of pyrazinamide?
Hepatotoxicity
Hyperuricemia
What are the side effects of ethambutol?
Optic neuritis: test visual acuity and color vision
What happens during the Initial (Intensive) Phase?
4 meds daily x 2 months
Then repeat the CXR, AFB smear and culture to see how they’re doing
What happens in the Continuation phase of active TB and how long does it last?
Rifampin and Isoniazid daily OR twice a week x 4 months
How does TB treatment change if the patient is HIV+
Extended by 9-12 months
Which of the 4 TB drugs do you not give to pregnant women?
Pyrazinamide
Which TB drug do you not give to babies and children?
Ethambutol 👁
Don’t want them to go blind
What conditions must be met to be considered not contagious anymore after starting TB treatment?
2 weeks of treatment regimen
3 negative sputum smears
Symptoms improve
(So yes you could potentially come out of quarantine and go home before the culture even comes back)
What are the rules for going home while you’re still contagious if you have TB?
DOT has to come watch you take your meds every day
No children under 5 in the home
No immunocompromised ppl in the home
Can only leave the house to go to the doctor
Strict follow up
TB treatment is based on (duration of treatment/number of doses)
Number of doses
How many doses of TB meds are taken during the Initial phase of TB treatment?
56 doses
Everyday for 8 weeks
How many doses of TB meds are taken in the Continuation phase?
Continuation phase 18 weeks:
126 doses (daily) Or
36 doses (twice weekly)
Which drug do you give to treat Latent TB in pregnant women and kids 2-11?
Isoniazid
300mg daily x 9 months
Or 900mg twice a week x 9 months
(I don;t know if the doses/length of treatment are important)
What is the brand new preferred treatment of latent TB in adults and children 12 and up?
Isoniazid + Rifapentine
12 weekly doses under DOT
*****
(The once weekly dose x 12 weeks seems important to know)
Is DOT necessary for the treatment of latent TB?
Yes
Can you give the fancy new Isoniazid+Rifapentine therapy to pregnant women with latent TB?
No
Can you give the fancy new Isoniazid+Rifapentine drug to HIV+ people for treating latent TB?
Yes
What should you give to treat latent TB if your patient can’t take Isoniazid?
Rifampin
Daily x 4 months
Who needs to be tested for TB?
People with high risk of exposure (IVDU, etc)
People with high risk for developing disease once infected (HIV)
Healthcare workers
MDR-TB does not respond to which drugs?
Isoniazid
Rifampin
XDR-TB is resistant to even more drugs than MDR-TB, including fluoroquinolones. How do you treat it?
Surgery to remove necrotic tissue
We don’t give the BCG vaccine in America except to these 2 groups of people:
Children w/ negative TST and continuous exposure (like mom or dad has TB)
Healthcare workers with HIGH risk of MDR-TB (like Doctors Without Borders stuff)
You get Histoplasmosis from_____________
Soil contaminated with bird or bat shit
🦜🦇💩
What part of the country do you find Histoplasmosis?
Ohio and Mississippi River valleys
What kind of activities puts someone at high risk for Histoplasmosis?
Spelunking lmao **
Chicken coops
Construction, gardening, roofing, installing AC units (?)
What are the 4 presentations of histoplasmosis?
Asymptomatic Primary Histoplasmosis (90%)
Acute Symptomatic Histoplasmosis
Progressive Disseminated Histoplasmosis
Chronic Pulmonary Histoplasmosis
Do most people with histoplasmosis get symptoms?
No
How do you treat symptomatic histoplasmosis?
You usually don’t.
Self -limited
How do you treat asymptomatic histoplasmosis?
No treatment ***
What kind of patient will develop Progressive Disseminated Histoplasmosis?
AIDS patients
What kind of patient will develop Chronic Pulmonary Histoplasmosis?
Old peopel with COPD
Let’s face it their lungs were already circling the drain
How do you test for Histoplasmosis?
Enzyme immunoassay of Urine** or serum
(She had the urine part underlined)
There were two other tests on the slide: immunodiffusion and complement fixation. Seems unimportant though
What disease can Histoplasmosis mimic on CXR?
TB
What does histoplasmosis look like on CXR?
Hilar adenopathy
Patchy/nodular infiltrates in lower lobes
How do you contract Coccidiomycosis (Valley Fever)?
Inhaling spores in contaminated soil
Where do you find Coccidiomycosis?
Lower deserts of Western Hemisphere AKA Arizona
Do most people show symptoms if they have Valley Fever?
No
60% are asymptomatic
What is sub-acute valley fever?
A mild, self limited bout of vague respiratory symptoms that go away on their own and are protective from future disease
What are the symptoms of a primary infection of Cocci/Valley Fever?
Marked fatigue**
Erythema nodosum**
Erythema multiforme
Plus regular pneumonia sx
What happens with disseminated disease form of cocci/valley fever?
Goes to your lungs, bones, and brain
In HIV+, African/Filipino descent, or 3rd trimester of pregnancy
Do you usually need to treat cocci/valley fever?
No
What is her take home point of treating cocci/valley fever
Recognizing the disease and treating early is critical **
You should think of Cocci if a patient comes in with pulmonary complaints and has one or more of these:
The 3 E’s:
Erythema Nodosum
Erythema Multiforme
Eosinophilia
How do you treat Cocci in patients who are at high risk of developing disseminated disease?
-azole
Amphotericin B if pregnant
What ethnicities are hit hardest by cocci/valley fever?
African
Filipino
What two events can increase chances of cocci/valley fever exposure?
Dust storm
Earthquake
