Pulm Infectious Diseases (Handorf) Flashcards
Bacterial pneumonia and associated inflammation cause lung tissue to:
consolidate (firm to the touch)
How does bronchopneumonia affect lung tissue? What does this suggest?
patchy consolidation
suggests distribution from terminal bronchioles
Most common pathogen causing bronchopneumonia:
Streptococcus pneumoniae
How does lobar pneumonia affect lung tissue? What are the stages of its progression?
consolidation of a whole lobe or a large part of a lobe
congestion, red hepatization, grey hepatization, resolution
Under what conditions would you see lobar pneumonia?
virulent organism and/or compromised host
Describe the histopathology of acute pneumonia.
congested septal capillaries
extensive neutrophil exudation into alveoli
In early organizing pneumonia, what is seen microscopically?
intra-alveolar exudate streaming through pores of Kohn
In advanced organizing pneumonia, what is seen microscopically?
exudate transformed to fibromyxoid masses
macrophages and fibroblasts present
What stage does acute/early pneumonia correspond to? Advanced?
- red hepatization
2. grey hepatization
What is a classic sign of Klebsiella pneumonia in a patient?
Currant jelly sputum
blood and mucous
How does Klebsiella pneumonia appear microscopically?
Large encapsulated “boxcar” Gram-negative rods
Lung scarring after infection relates to:
severity
organism (viral more likely to scar than bac)
In acute bacterial pneumonia, what causes hypoxia?
polys in alveoli
Describe primary atypical pneumonia.
What organism is usually responsible?
acute febrile respiratory illness with patchy lung inflammation, primarily septal/interstitial
Mycoplasma pneumoniae
When death occurs in viral pneumonia, it usually does so due to:
superimposed (bacterial) infection
Pulmonary fungal infections are primarily caused by what 2 organisms?
How do these appear microscopically?
histoplasmosis (crowded into histiocytes)
blastomycosis (broad based budding yeast; “snowman”)
Who is more at risk of TB infection?
males economically disadvantaged inner city residents alcoholics drug abusers recent immigrants
Describe:
primary phase TB infections
secondary phase TB infections
progressive phase TB infections
Ghon complex; usually clinically inapparent
reactivation; apical consolidation and granuloma
associated with cavitary fibrocaseous TB, miliary TB or TB bronchopneumonia
Where are TB infections typically localized?
apices (more O)
How do TB infections spread within the lungs?
from periphery to hilum
Miliary TB is associated with:
massive hematogenous dissemination (spleen, lung, brain, etc) and MOF
TB is associated with what type of lesion?
caseating
Describe a pulmonary abscess
A local suppurative process within the lung characterized by necrosis of lung tissue
How do pulmonary abscesses present clinically?
Clinical “chronic pneumonia” with cough, fever, weight loss, copious foul smelling sputum
Causes of pulmonary abscess?
Aspiration—alcoholism, anesthesia Antecedent acute pneumonia Septic embolism Neoplasm—”postobstructive pneumonitis” Miscellaneous—direct spread from adjacent organ
Common immune suppression related pulmonary infections include:
pneumocystis, histoplasmosis, Aspergillus and tuberculosis
Histopath associated with Pneumocystis:
fluffy looking intraalveolar exudate
organisms look like “deflated soccer balls”
How does Aspergillus affect lung tissue?
angioinvasive: propensity to infarct surrounding tissues by growing into and occluding vessel lumens
may form “fungus ball”
