Baker/Parks: Infectious Diseases of the Lung

Question 1

Self-limited inflammation of the large* airways of the lung that is characterized by cough without pneumonia
Usually no fever
“Chest cold”
VERY common

Answer 1

Acute bronchitis

Question 2

What usually causes acute bronchitis?

Answer 2

viruses
infleunza A and B
parainfluenza virus
RSV
coronavirus
adenovirus

Question 3

How long must the cough last for it to be acute bronchitis?

Answer 3

more than 5 days

**typically lasts 10-20 days, and sometimes longer than 4 weeks

Question 4

What will you find on pulmonary exam with a patient with acute bronchitis? What will you find on CXR?

Answer 4

usually normal pulmonary exam, maybe some wheezing

CXR usually normal - not indicated, may see some non-specific bronchial wall thickening

Question 5

Acute bronchitis is made worse by (blank)

Answer 5

smoking

Question 6

Should antibiotics be used for acute bronchitis?

Answer 6

NO!!!

**usually viral

Question 7

T/F: Pneumonia can be caused by bacteria, viruses, and fungus
It causes significant morbidity and mortality

Answer 7

True

**9th leading cause of death in the US

Question 8

What causes community acquired pneumonia?

Answer 8

bacteria or viruses or both!!

**Think Strep pneumo, H flu, Moraxella catarrhalis, Staph aureus

Question 9

Predisposing conditions for community acquired pneumonia?

Answer 9

extremes of age
presence of chronic conditions
immune deficiencies

Question 10

Compare lobar pneumonia to bronchopneumonia in terms of degree and pattern of consolidation

Answer 10

lobar pneumonia - large portion or whole lobe consolidation

bronchopneumonia - patchy consolidation

Question 11

Four stages of community acquired lobar pneumonia?

Answer 11

1. congestion
2. red hepatization
3. gray hepatization
4. resolution

Question 12

Reaction to inflammation if consolidation extends to the pleura

Answer 12

pleuritis

Question 13

While there may be complete clearance of infection from the pleura, fibrin may organize and leave (blank)

Answer 13

permanent scarring

Question 14

Patchy
Often mutilobar
Sometimes bilateral
Lower lobe predominance
Similar mechanism
Suppurative, neutrophil rich exudate in bronchi, bronchioles and alveolar spaces

Answer 14

bronchopneumonia

Question 15

Clinical features of community acquired pneumonia

Answer 15

abrupt onset with fever and chills
cough with mucopurulent sputum
may be some pleuritic chest pain
crackles on auscultation, dullness to percussion

Question 16

Complications of community acquired pneumonia?

Answer 16

pulmonary abscess
infected pleural effusion –> empyema
bacterial dissemination

Question 17

How to treat community acquired pneumonia?

Answer 17

antibiotics!!!
vaccinate!
thoracentesis for pleural effusion/empyema

Question 18

Acute, febrile respiratory condition with patchy inflammatory changes in the lungs.
Generally confined to the alveolar septa and pulmonary interstitium
Moderate amount of sputum
No physical findings of consolidation
Only moderately elevated WBC
Lack of alveolar exudate

Answer 18

Atypical pneumonia

Question 19

What usually causes atypical pneumonia

Answer 19

**most commonly Mycoplasma pneumoniae
also Chlamydia pneumoniae
Influenza A/B, RSV, etc

Question 20

What distinguishes atypical pneumonia from acute bronchitis?

Answer 20

site of infection!

bronchitis: bronchial wall
atypical pneumonia: alveolar septum and interstititum

Question 21

In atypical pneumonia, where will you see infiltration of lymphocytes and monocytes?

Answer 21

in the interstitial space!

**around the edges of alveoli

Question 22

Common in patients with
Severe underlying disease
Immunosuppression
Prolonged antibiotic therapy (resistance)
Invasive intravascular access
Mechanical ventilation – VERY high risk
Potentially life threatening

Answer 22

Hospital acquired pneumonia

Question 23

What bugs cause hospital acquired pneumonia?

Answer 23

gram negative rods!
pseudomonas aeruginosa, enterobacteriaceae, Klebsiella
Also staph aureus

Question 24

Inhalation of gastric contents
Debilitated patients
Stroke, intoxication or other causes of altered mental status
Occurs while unconscious or during vomiting
Common in alcoholics

Answer 24

Aspiration pneumonia

Question 25

How is aspiration pneumonia different from aspiration (chemical) pneumonitis?

Answer 25

multiple organisms are aspirated these pts get very sick very quickly possible lung abscess and ARDS as complications

Question 26

Suppurative destruction of the lung parenchyma within a central area of cavitation, liquefactive necrosis

Answer 26

lung abscess

Question 27

How do lung abscesses get to the lung?

Answer 27

``` aspiration post-pneumonic septic emboli from distant infections obstructive (neoplastic conditions) trauma, infected adjacent organs, hematogenous seeding (bacteremia) ```

Question 28

How will people with lung abscesses present?

Answer 28

cough fever copious foul-smelling purulent sputum clubbing

Question 29

Typically localized lesion | Granulomatous inflammatory reaction

Answer 29

Chronic pneumonia

Question 30

What usually causes chronic pneumonia?

Answer 30

mycobacterium TB | fungi: histoplasma, blastomyces, coccidioides

Question 31

Clinical presentation and morphology are very similar to TB Intracelluar parasite of macrophages Self-limited and latent 1o infection Chronic progressive 2o disease Fever, night sweats, cough Localized extrapulmonary involvement Wide dissemination in immunocompromised patients

Answer 31

Histoplasmosis

Question 32

This disease presents like TB, with granuloma formation with caseation necrosis. Granulomas can become fibrotic and calcify.

Answer 32

Histoplasmosis

Question 33

How do you distinguish histoplasmosis from TB?

Answer 33

yeast on tissue exam culture antibody testing

Question 34

Macrophages have limited ability to ingest and kill this dimorphic fungus Calls in neutrophils, which leads to suppurative granulomas Causes pulmonary, disseminated, and primary cutaneous infections

Answer 34

Blastomycosis

Question 35

How does blastomycosis infect the skin?

Answer 35

when the fungus is directly innoculated to the skin **can be mistaken for squamous cell cancer due to epithelial hyperplasia

Question 36

``` San Joaquin Valley Fever Most in endemic areas have been infected Most primary infections are asymptomatic 10% have lung lesions Fever, cough, pleuritic chest pain Erythema nodosum or Erythema multiformae Granulomatous or pyogenic (suppurative) or both Depends on if spherules remain intact Rupture and release of endospores results in a pyogenic reaction Rarely ( ```

Answer 36

Coccidioidomycosis

Question 37

Ubiquitous mold that can cause allergies*, invasive lung disease in immunocompromised host, and pulmonary lesions

Answer 37

Aspergillus fumigatus

Question 38

Risk factors for Mycobacterium TB infection?

Answer 38

poverty crowding chronic disease

Question 39

If you are infected with Mycobacterium TB, do you have disease manifestations?

Answer 39

not always | Primary TB is typically asymptomatic, but it can remain dormant and reactivate when immunity is down

Question 40

What type of cell-mediated reaction does Mycobacterium TB cause? What do you look for when administering the PPD skin test?

Answer 40

type 4 delayed sensitivity reaction; | look for palpable induration

Question 41

A lesion seen in the lung that is caused by tuberculosis | The lesions consist of a calcified focus of infection and an associated lymph node.

Answer 41

Ghon complex **Ghon focus is the calcified region of infection

Question 42

What will be seen in both the lung and lymph node in a Gohn complex in a patient with TB?

Answer 42

caseous necrosis

Question 43

For granulomas to develop in TB, what factor is necessary? This explains why Crohn's disease and RA can cause reactivation of TB

Answer 43

TNF is key!!

Question 44

This factor activates macrophages and can be used in an assay to test for latent TB

Answer 44

IFN gamma

Question 45

Secondary (mostly) Reactivation TB Usually years after Primary Infection when host resistance is down Can be from an exogenous source Classic location of lesions is at the apex of the lung Pre-existing hypersensitivity activates and walls off the infection --> caseous necrosis Erosion into airways leads to coughing up TB laced sputum Erosion into blood vessels leads to hemoptysis

Answer 45

Secondary (reactivation) TB

Question 46

How will patients with reactivation TB present?

Answer 46

malaise, anorexia, weight loss --> CONSUMPTION fever that is remittant night sweats hemoptysis and pleuritic chest pain may be present

Question 47

What can be done to diagnose TB? What MUST be done?

Answer 47

``` clinical picture culture acid fast stain of sputum or BAL fluid PCR (nucleic acid testing) for Tb DNA TNF assay ``` **must identify tubercle bacilli

Question 48

TB mixed with this immunodeficiency is a bad bad thing

Answer 48

HIV * *with HIV, you may get false negative sputum or PPD test * *you have higher bacterial loads, but decreased T cell activity, so you get cavitation and erosion :(