Pathology of pulmonary infection Oct20 M1 Flashcards
4 categories of pulmonary infections
diffuse parenchymal (lobar) patchy parenchymal (bronchopneumonia) interstitial nodular (granulomatous)
location of lobar (airspace) pneumonia
lower lobe, peripherally
mechanism of diffuse parenchymal (lobar) infection
aspirate organism, grows near resp bronchiole, acute inflammation causes outouring of fluid in airspace
mechanism of diffuse parenchymal (lobar) infection: what happens after outpouring of fluid in airspace
fluid flows between alveoli, bacteria displaces, fluid in airways increases, consolidation of the lung. cells replace fluid with time
lobar (airspace or diffuse parenchymal) pneumonia prognosis and why
can heal completely (no necrosis, lung itself not injured)
bronchopneumonia (patchy disease) location
at primary site of infection and can affect both lungs and the bronchi
bronchopneumonia (patchy disease) pathogenesis (where starts, etc.)
start at terminal bronchiole, pluggs airways, distant atelectasis, collapsed areas are surrounded by congestion, collapse and emphysema
bronchopneumonia (patchy disease) how resolves
- resolution of exudate solves problem
- may have fibrosis (if organisation occurs)
- may cause abcesses (necrosis) if aggressive
empyema def
greenish pus lining pleural surface (neutrophilic)
when can see empyema
as complication of bronchopneumonia
interstitial pneumonia location
mostly basal and peripheral
what is affected in interstitial pneumonia
interstitium but may also affect airspace
least severe interstitial pneumonia findings
diffuse parenchymal interstitium inflammation with normal airspaces
mild interstitial pneumonia findings
lymphocyte infiltrate in parenchymal IS. normal septum but mild thickening in IS
diffuse alveolar damage in interstitial pneumonia def
inflammation, tissue necrosis, esoinophilic exudate (proteins, neutrophils, necrotic tissue, hyaline membranes), fluid can leak to adjacent capillaries, consolidation of alveolar space
what causes diffuse alveolar damage
measles pneumonia
what causes diffuse parenchymal (lobar) pneumonia
viruses, bacteria, fungi
what causes bronchopneumonia (patchy disease)
toxins, bacteria and viruses
what causes interstitial pneumonia
infectious agents, viruses (cytomegalovirus)
nodular (granulomatous) pulmonary infection example
TB
initial TB
inflammation with neutrophils and fibrinous exudate
TB as advances
necrosis center surrounded by epitheloid histiocytes
advanced TB findings
expanding necrosis, walled off by fibrosis, multinucleated giant cells + lymphocyte + fibrosis in healing granuloma
healed TB finding
Ghon focus (caseous), necrosis completely surrounded by fibrosis
TB lung region affected
parenchyma of middle-lobe
TB: what happens after mycobacteria reaches parenchyma
mycobacteria drains to lymph nodes and triggers inflamm there
what happens in lymph nodes when see TB
T cells activate macrophages
most frequent site for secondary TB (TB reactivation) and why
apex bc TB survives more there
what secondary TB may look like on CXR
cavitation in upper lobe (grey space)
miliary TB def
diff nodules spread of TB in the lung
miliary TB how happens
TB spreads to other places in the lung using the pulmonary vasculature
when see miliary TB
cancer therapy, immunosuppression
