Ch.7 - Recognizing Pneumonia Flashcards
Segmental pneumonia:
Prototype: staph pneumonia.
Tends to be multifocal, does not have air bronchograms, and can be associated with volume loss because the bronchi are also filled with inflammatory exudate.
Interstitial pneumonia:
Prototype: Viral pneumonia, or PCP.
Tends to involve the airway walls and alveolar septa and may produce, especially early in the course, a fine, reticular pattern in the lungs.
Later in the course, it produces airspace disease.
Round pneumonia:
Prototype (hemophilus):
Usually occurs in children in the lower lobes posteriorly and can resemble a mass, the clue being that masses in children are uncommon.
Cavitary pneumonia:
Prototype: TB.
Has lucent cavities produced by lung necrosis as its hallmark.
Post-primary TB usually involves the upper lobes.
It can spread via a TRANSBRONCHIAL route that can infect the opposite lower lobe or another lobe in the same lung.
Aspiration:
- Can be bland and clear quickly.
- Can be infected and take months to clear.
- May form a chemical pneumonitis which can take weeks to clear.
Pneumonia can be localized by:
Using the silhouette sign + the spine sign as aids.
Pneumonias frequently resolve by:
Breaking up so that they contain patchy areas of newly aerated lung within the confines of the previous pneumonia –> VACUOLIZATION.
When pneumonias may contain air bronchograms?
If the BRONCHI THEMSELVES are NOT filled with inflammatory exudate or fluid.
Air bronchograms are much more likely to be visible when?
The pneumonia involves the CENTRAL portion of the lung near the hilum.
Near the periphery, the bronchi are too SMALL to be visible.
Is an air bronchogram specific for pneumonia?
NO - Anything of fluid or soft tissue density that replaces the normal gas in the airspaces may also produce this sign.
Except for the presence of air bronchograms, airspace pneumonia is usually …?
Homogenous in density.
In some types of pneumonia (ie bronchopneumonia), the BRONCHI, as well as the airspaces, contain inflammatory exudate. This can lead to what?
ATELECTASIS associated with the pneumonia.
To sum up, 6 key sings of pneumonia:
- More OPAQUE than surrounding normal lung.
- Airspace disease –> Margins may be fluffy + indistinct except whee they abut a pleural surface like the interlobar fissures where the margins will be sharp.
- Interstitial pneumonias –> Prominence of interstitial tissues of the lung in the affected area. Disease may spread to ALVEOLI and resemble airspace disease.
- Pneumonias tends to be homogenous in density.
- Lobar pneumonias may contain air bronchograms.
- Segmental pneumonias may be associated with ATELECTASIS in the affected portion of the lung.
5 patterns of appearance of pneumonias:
- Lobar.
- Segmental.
- Interstitial.
- Round.
- Cavitary.
Lobar pneumonias almost always produce … and almost always contain … .
A silhouette sign.
Air bronchograms.
The prototypical bronchopneumonia is caused by?
S.aureus. Many Gram(-) bacteria, such as P.aeruginosa, can produce the same picture.
Patterns that might suggest a causative organism - TB?
Upper lobe cavitary pneumonia with spread to the OPPOSITE LOWER LOBE.
Patterns that might suggest a causative organism - K.pneumoniae?
Upper lobe lobar pneumonia with BULGING INTERLOBAR fissure.
Patterns that might suggest a causative organism - P.aeruginosa or anaerobes?
LOWER lobe CAVITARY pneumonia.
Patterns that might suggest a causative organism - P.jiroveci?
Perihilar interstitial disease OR perihilar airspace disease.
Patterns that might suggest a causative organism - Coccidioides, TB?
Thin-walled upper lobe cavity.
Patterns that might suggest a causative organism - Strep, staph, TB?
Airspace disease with effusion.