Bacterial and Fungal Pneumonias; Tuberculosis

Question 1

What is the number one leading cause of death from infectious disease?

Answer 1

complicates the course of 1/20 hospital patients

Question 2

How do smoking and alcoholism predispose to pneumonia?

Answer 2

Smoking - paralyzes cilia, also predisposes to COPD

Alcoholism - malnutrition, depressed level of consciousness, and poor ciiary function

Question 3

What pneumonias are transmitted by inhalation of airborne organisms?

Answer 3

1. Mycoplasma
2. Tuberculosis
3. Legionella
4. Fungi

Question 4

In what situations might you get hematogenous spread which leads to pneumonia?

Answer 4

IV drug users, infected IV lines, bloodborne infections from elsewhere in the body

Question 5

How will a lobar pneumonia present via auscultation, percussion, and vocal fremitus? What classically causes this?

Answer 5

Auscultation - bronchial breath sounds
Percussion - dullness
Vocal fremitus - increased vibrations

Classically caused by S. pneumoniae, but need to keep in context the situation (nosocomial vs community acquired vs immunosuppressed)

Question 6

What will patchy or interstitial pneumonia cause on auscultation?

Answer 6

rales (crackles)

Question 7

How will pleural effusion present on tactile fremitus?

Answer 7

Decreased transmission

Question 8

Associate each of the following sputum consistencies with a microbe:

1. Rusty
2. Currant jelly
3. Creamy yellow
4. Foul odor

Answer 8

Rusty - S. pneumoniae
Currant jelly - Klebsiella pneumoniae
Creamy yellow - S. aureus
Foul odor - anaerobes

Question 9

What is the definition of a good sputum sample?

Answer 9

<10 epithelial cells and >25 PMNs per low power field

Question 10

Who is mycoplasma pneumonia common in and how does its constitutional symptoms differ from S. pneumonia (usual)?

Answer 10

Occurs in young, healthy people, especially in outbreaks at school or in military recruits in fall and winter

Mycoplasma is an atypical so it has a more insidious onset (rather than abrupt), a nonproductive cough (rather than rusty sputum), and no leukocytosis

Question 11

How does Mycoplasma appear on CXR and what is one rare but very specific finding seen in this infection?

Answer 11

CXR: Patchy bronchopneumonia, will cause rales on physical exam sometimes

Bullous myringitis - inflammation of tympanic membrane

Question 12

Who typically gets Legionella?

Answer 12

Immunosuppressed, smokers, COPD, advanced age, male, with cardiac disease
-> need some degree of immunosuppression for severe infection

Question 13

What is the primary cardiac symptom of Legionella? What treatment against it is effective?

Answer 13

Relative bradycardia
-> patient’s heart rate will only be high normal, which is lower than expected given how high their fever is

Treatment: Macrolides (think of crows on the crane)

Question 14

What bacterial pneumonia occurs in COPD and is known for a very large amount of sputum production?

Answer 14

Haemophilus influenzae

Question 15

What pneumonia is known for a lobar pneumonia causing bulging fissures because there is so much exudate? Who does it occur in?

Answer 15

Klebsiella pneumoniae

Occurs in alcoholics and diabetics

Question 16

What types of pneumonias are known for causing an air-fluid level on CXR?

Answer 16

Necrotizing pneumonias like S. aureus, P. aeruginosa, and ESPECIALLY anaerobic pulmonary infections -> cause a cavity lung abscess

Question 17

What is the treatment for anaerobic pneumonias? Is the course of the disease typically acute or chronic?

Answer 17

Long course of penicillin and clindamycin

Typically a subacute / chronic course - with h/o poor dental hygiene, malaise, and foul-smelling sputum

Question 18

What pneumonia is marked by a slowly progressive infection causing worsening CXR infiltrates and hypoxemia in HIV patients? What is the treatment?

Answer 18

Pneumocystis jirovecii pneumonia

Treatment: TMP/SMX first line, with pentamidine IV if allergic (think of the pentagon ping pong paddles)

Question 19

What does skin testing for coccidioides mean if it goes from negative to positive or positive to negative?

Answer 19

Negative to positive: new infection

Positive to negative: severe or disseminated disease

Question 20

What is the usual testing used to detect Coccidioides which may be missing the diagnosis depending on when this is done? Why might this be preferred over cell culture?

Answer 20

IgM / IgG serologies

IgM positive after 2-4 weeks, IgG becomes positive later

High IgG titers is prognostic for a very high chance of disseminated disease

Preferred over culture because the mold grown in the lab is very infectious

Question 21

What are common and more specific symptoms of primary coccidioidomycosis?

Answer 21

Fever, cough, joint aches (guy kneeling in sketchy)

Erythema nodosum - think shin lesions on wall in sketchy

Question 22

Who is at highest risk for disseminated coccidioidomycosis and where does it tend to spread?

Answer 22

Young or old, immunosuppressed, blacks, mexicans, and native americans

Can disseminate to skin (erythema nodosum) or cause fatal meningitis (think of guy leaning on immunocompromised fountain with neck brace)

Question 23

Who is at greatest risk for chronic and disseminated histoplasmosis?

Answer 23

Chronic - patients with COPD

Disseminated - Immunocompromised, can spread like miliary TB

Question 24

What are the diagnostic tests best used for diagnosis of histoplasmosis and blastomycosis?

Answer 24

Histoplasmosis - urine and serological testing (think of red and yellow stalactites in sketchy)

Blastomycosis - Culture is definitive, organism grows fast

Question 25

How are aspergillus hypersensitivity pneumonitis and allergic bronchopulmonary aspergillosis (ABPA, associated with asthma) treated? What will CXR and serology show?

Answer 25

Treat with corticosteroids, or avoidance of Aspergillus

CXR shows migratory infiltrates, serology shows elevated IgE

Question 26

In what patient populations do we see aspergilloma and invasive aspergillosis?

Answer 26

Aspergilloma - site of pre-existing cavity (i.e. old TB) -> may need surgical excision to prevent vascular invasion, but rarely treated

Invasive aspergillosis - post transplant or bone marrow irradiation in immunocompromised, very high mortality

Question 27

How are nontuberculous mycobacterial infections diagnosed definitively and why?

Answer 27

They may be just colonizers or actually pathogens

Diagnosed by at least TWO positive sputum cultures, or ONE positive culture from bronchial lavage / biopsy.

Question 28

How are different nontuberculous mycobacteria told apart, and how do they appear on CXR?

Answer 28

Told apart by growth rate and specific pigment production

CXR - nodular or cavity lesions

Question 29

What are risk factors for reactivation of latent TB?

Answer 29

Silicosis, HIV, substance abuse, corticosteroids / immunosuppressives, organ transplant, inflammatory bowl diseases, diabetes, etc

Question 30

If a TB treatment regimen is failing, what should you do?

Answer 30

Add on at least TWO more medications, never just one, since resistance is likely

Question 31

What is required for positive diagnosis of TB via sputum sampling?

Answer 31

At least three sputum samples taken 8 hours apart, with at least one being a morning sample

Three positives required, negative does not exclude TB

-> use these for culture in broth, 4-14 days

Question 32

Where should the PPD skin test be injected?

Answer 32

INTRAdermally (not subdermally), can see 2-8 weeks after infection

Question 33

What is the rule used to interpret a positive PPD test?

Answer 33

5/10/15 mm rules

5 or more: positive if HIV, CXR consistent with TB, any immunosuppression, or recent TB contacts

10mm or more: recent travel from high prevalence area, IV drug use, lab personnel, age <5 (common in young children), BCG vaccine falls here

15mm or more: positive even with no other known factors

Question 34

How do the lymphocyte tests for TB work?

Answer 34

3 tubes or plates are run

Plate / Tube 1: lymphocytes alone (proliferation = background noise, nil

Plate / Tube 2: Lymphocytes + TB antigen

Plate / Tube 3: Lymphocytes + Known mitogen, positive control

Response is equal to plate 2 minus plate 1 (background noise). Certain threshold = sensitization vs TB = infection