Pulmonary I Flashcards
Chronic Inflammation
Acute Inflammation
Polymorphonuclear cell (PMN) - Acute inflammation
Neutrophils
Mononuclear Cells - Chronic Inflammation
What is a granuloma composed of?
Th1 cells, B cells on outside, Multinucleated giant cells surrounding necrotic core and persistent antigens
Granulomatous inflammation
Granulomatous inflammation
Normal Alveolar Tissue
Normal lung histology
Normal lung histo
Normal Lung
Acute Bronchopneumonia
Patchy infiltrates
Typical organisms: Streptococcus pneumoniae, Staphylococcus aureus, Pseudomonas aeruginosa, Hemophilus influenzae, and Klebsiella pneumoniae (among others)
Acute Bronchopneumonia (lobular)
Areas of tan-yellow consolidation, firmer and more raised than surrounding lung
Remaining lung is dark due to pulmonary congestion
Acute bronchopneumonia
Higher magnification, pattern of patchy distribution seen
Consolidated areas closely match pattern of lung lobules (“lobular pneumonia”)
Bronchopneumonia is classically hospital acquired.
Typical organisms: S. aureus, Klebsiella, E. coli, Pseudomonas
Acute Bronchopneumonia
Acute Bronchopneumonia Histology
Acute lobar pneumonia
More extensive than bronchopneumonia, all of one lobe is consolidated
Lobar pneumonia + fibrinous pleuritis
If there’s exudate on the surface, may become empyema
Lobar pneumonia + fibrinous pleuritis
May result in empyema (collection of pus in pleural space)
Lobar pneumonia + Gray-white hepatization of lower lobe
Filled with leukocytes
Lobar pneumonia + gray-white hepatization
Acute pneumonia
Acute Bronchopneumonia
Lobar pneumonia
Bronchopneumonia
Lobar pneumonia
Lobar pneumonia
Acute lobar pneumonia
Aspiration pneumonia
Usually mixed infection & right airways more vertical, so more common in R. lung
Contains multinucleated giant cells
Contains neutrophilic exudate and dark blue bacterial colonies suggests aspiration or hematogenous spread of infection to lung. Aspirated material from oral-pharyngeal region has bacterial flora. Hematogenous spread of infection to lungs could occur from septicemia or infective endocarditis involving right side of heart
Aspiration pneumonia
Aspiration Pneumonia
Aspiration Pneumonia
2 lung abscesses (one in upper, one in lower lobe)
Adjacent areas of tan consolidation w/ bronchopneumonia
Abscess = complication of severe pneumonia, most typically from virulent organisms (S. aureus)
Usually a complication of aspiration, more frequent in R. posterior lung
Lung Abscess + bronchopneumonia
Several abscesses w/ irregular, rough-surfaced walls seen w/in areas of tan consolidation
If large enough, abscesses will contain liquefied necrotic material & purulent exudate that often results in air-fluid level by chest radiograph in abscess
Lung Abscess
Purulent exudate has drained following sectioning to reveal abscess cavities
Abscesses can be source for septicemia and difficult to treat
Lung Abscess
Lung Abscess
More virulent bacteria and/or more severe pneumonias can be assoc. w/ destruction of lung tissue & hemorrhage
Alveolar walls no longer visible because early abscess formation (also hemorrhage)
Timeline of Tuberculosis
Ghon Complex
Small tan-yellow sub-pleural granuloma in mid-lung field on right. In hilum, small yellow-tan granuloma in hilar lymph node next to bronchus (Gohn Complex) - characteristic of primary TB. In most people, granulomatous disease doesn’t progress. Over time, decreases in size & can calcify, leaving focal calcified spot on chest radiograph, suggesting remote granulomatous disease.
Gohn Complex
Closer Gohn Complex. Primary TB is pattern seen with initial infection w/ TB in kids. Reactivation (secondary) TB more common in adults.
Secondary (reactivation) tuberculosis
Most commonly involves apex of lungs (contain higher O2 content, and mycobacterium is aerobic)
Granulomas have areas of caseous necrosis. This is very extensive granulomatous disease. This pattern of mutliple caseating granlumonas primarily in upper lobes most characteristic of secondary (reactivation) TB. However, fungal granulomas (histoplasmosis, crytococcosis, coccidioidomycosis) can mimic pattern.
Secondary (Reactivation) Tuberculosis
When there is extensive caseation & granulomas involve larger bronchus, it’s possible for much of soft, necrotic center to drain out and leave behind a cavity. Cavitation is typical for large granulomas with TB. Cavitation more common in upper lobes.
Miliary TB
Miliary TB
Miliary TB
When immune response poor or overwhelmed by extensive infection, can see “miliary” pattern because there are many small tan granulomas 2-4 mm scattered throughout lung parenchyma. Called miliary because looks like small millet seeds.
Miliary TB
Miliary TB
At closer range, miliary pattern seen throughout lung. Dissemination of infectious agent (M. tuberculosis, fungi) may produce a similar pattern in other organs
Miliary TB
Low power magnification, multiple granulomas.
Langhans-type giant cell in granulomatous inflammation
At high magnification, granuloma demonstrates that eptihelioid macrophages elongated with long, pale nuclei and pink cytoplasm. Macrophages organize into committees called giant cells. Typical giant cell for infection = Langhan’s cell and has nuclei lined up along one edge of cell (Horseshoe). Process of granulomatous inflammation takes place over months to years.
Granulomas are composed of transformed macrophages (epithelioid cells) along with lymphocytes, occasional PMNs, Plasma cells, and fibroblasts.
Epithelioid response in granuloma
Caseous necrosis in TB
Edge of granuloma shown here at high magnification. At upper right is amorphous pink caseous material composed of necrotic elements of granuloma as well as infectious organisms. Area ringed by inflammatory component with epithelioid cells, lymphocytes, and fibroblasts.
Acid-Fast Bacilli on Ziehl-Neilson Stain
In order to find the mycobacteria in a tissue section, a stain for acid fast bacilli is done (AFB). The mycobacteria stain as red rods (seen here).
Gold standard is a culture, but that could take weeks.
Fungal abscess
Here is a fungal granuloma. Note the sharply demarcated borders to this granuloma, which give it a discrete, spherical appearance both grossly and radiographically.
Fungal Hyphae of Aspergillus
Hyphae = mold form with filament structures, branch at 45 degree angles (but not the only fungus that does so)
Has propensity to invade blood vessels
What is a dimorphic fungus?
Grows usually as mold in environment, but as yeast in the body (often due to bird/bat feces)
2 examples: Coccidioidomycosis (More common in SW) and Histoplasmosis (more common in Midwest)
Coccidioides immitis spherules
Well-formed granuloma has large Langhans giant cell in center. Two small spherules of Coccidiodes immitis are seen in the giant cell.
Coccidioides immitis spherules
At high magnification, thick wall of C. immitis spherule is seen in giant cell in center of image. Spherule contains endospores. In nature C. immitis exists in hyphal form with characteristic alternating arthrospores.
Coccidioides immitis spherules high magnification
Histoplasma granuloma (calcified)
Histoplasmosis within macrophages
What are the differences between acute and chronic inflammation?
- Duration, inflammatory cells, vascular changes, Edema, Fibrosis, Systemic manifestation?
What is lobar pneumonia? How does it present? What organisms cause it?
Large, confluent areas of consolidation (i.e. entire lobes)
Much less common pattern than bronchopneumonia
Organisms: Streptococcus pneumoniae (pneumococcus) and Klebsiella
What is the pathophysiology of lobar pneumonia due to pneumococcus?
Inhalation -> Edema -> Red hepatization -> Grey hepatization -> Resolution
What is aspiration pneumonia characterized by?
Fairly localized inflammation centered around airways and/or small foci within alveolar tissue
Presence of foreign material in association with foreign body giant cell reaction
Describe the progression of TB
