Pneumonia & Suppurative Lung Diseases
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Transcript of Pneumonia & Suppurative Lung Diseases
Dr TTW (2009) 1
PNEUMONIA & SUPPURATIVE LUNG DISEASES
Dr. Thin Thin Win @ Safiya Yunus
Department of Pathology, PPSP
Dr TTW (2009) 2
PNEUMONIA
Definition
Inflammation of the lung parenchyma (alveoli) resulting consolidation or hardening of lung parenchyma
Dr TTW (2009) 3
Etiology
Caused by varieties of infectious agent such as bacteria, viruses, fungi, mycoplasma etc:…
Mostly bacterial pneumonia - (Pneumococci, Klebsiella pneumoniae, Staphylococci, Streptococci, H.influenzae, Pseudomonas aeruginosa) – Community acquired acute pneumonia
Dr TTW (2009) 4
Etiology
Result whenever pulmonary defense mechanism are impaired or resistance of host is lowered
Pulmonary defense mechanism –
1. cough reflex
2. mucociliary apparatus
3. phagocytic alveolar macrophages
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Clearing mechanism can be interfered with many factors:
1. Loss or suppression of cough reflex - aspiration of gastric contents in coma, anesthesia, neuromuscular disorders, drugs, chest pain – aspiration pneumonia
2. Injury to mucociliary apparatus – cigarette smoking, inhalation of hot or corrosive gases, viral infection, genetic disorders
Dr TTW (2009) 6
Clearing mechanism can be interfered with many factors:
3. Interfered phagocytic/ bactericidal action of alveolar macrophages
– alcohol, smoking, anoxia, O2 intoxication
4. Pulmonary congestion & edema
5. Accumulation of secretions
– cystic fibrosis & bronchial obstruction
Dr TTW (2009) 7
Aetiology & antomical pattern of pneumonia
Community acquired acute pneumonia
Community acquired atypical pneumonia
Aetiology Bacteria Virus
Mycoplasma
Clamydia
Anatomical involvement
Lobar pneumonia
Bronchopneumonia
Interstitial pneumonia
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Lobar pneumonia
Consolidation of a large portion of a lobe or an entire lobe
(whereas patchy consolidation in bronchopneumonia)
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Lobar pneumonia Bronchopneumonia
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A closer view of the lobar pneumonia demonstrates the distinct difference between the upper lobe and the consolidated lower lobe.
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Uniformly consolidated lower lobe in lobar pneumonia ( gray hepatization) – lower lobe become airless, liver like texture, gray white
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4 stages of inflammatory response in lobar pneumonia
Congestion Red hepatization Gray hepatization Resolution
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Stage of congestion
Lung – heavy, boggy, red Vascular engorgement Intra-alveolar fluid with few neutrophils & often
numerous bacteria
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Stage of red hepatization
Massive confluent exudation with red cells, neutrophils and fibrin filling the alveolar spaces
Gross – lobe appear distinctly red, firm & airless with liver-like consistency
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Stage of red hepatization
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Stages of gray hepatization
Progressive disintegration of red cells Macrophages replace PMN with fibrin
deposition Persistence of fibrinosuppurative
exudates Gross – grayish brown, dry surface
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Stages of gray hepatization
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Stage of resolution
Consolidated exudates within alveolar spaces undergoes progressive enzymatic digestion to produce a granular, semi fluid debris
Resorbed & ingested by macrophages, coughed up or organized by fibroblasts growing into it
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Stage of resolution (by organization)
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Bronchopneumonia
Patchy consolidation of lung May be one lobe or multilobar Frequently bilateral & basal
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Bronchopneumonia
Gross Lesions - 3 to 4 cm in diameter Slightly elevated, dry, granular, gray-red to
yellow Poorly delimited at margin
Histology Suppurative, neutrophil-rich exudates that fills
bronchi, bronchioles and adjacent alveolar spaces
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At higher magnification, the pattern of patchy distribution of a bronchopneumonia is seen.
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Bronchopneumonia
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Community acquired atypical pneumonia (Viral and Mycoplasma Pneumonia)Interstitial pneumonia
Morphology
Patchy or whole lobe Bilateral or unilateral Red-blue, congested & subcrepitant Pleuritis or pleural effusion is infrequent
Dr TTW (2009) 25
Community acquired atypical pneumonia (Viral and Mycoplasma Pneumonia)
Histology Inflammatory reaction in interstitial
tissue, virtually within the walls of alveoli Alveolar septa – widened, edematous
with mononuclear infiltrates of L, H, P & N in acute cases
Alveoli – free of exudates Pink hyaline membrane in alveolar walls
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Chronic Pneumonia
Localized lesion in Immunocompetent patient
Granulomatous inflammation → Mycobacterium tuberculosis, Fungal infection (Histoplasmosis, Blastomycosis, Coccidioidomycosis, Aspergillosis)
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Complication of pneumonia
1. Abscess formation
- due to tissue destruction & necrosis
2. Pleuritis, Pleural effusion, Empyema
- spread of infection to pleura cavity
causing intra-pleural fibrinosuppurative
reaction
Dr TTW (2009) 28
Complication of pneumonia
3. Organization of exudates
- convert portion of lung into solid tissue with fibrous scar
4. Bacterial dissemination
- to heart valves, pericardium, brain, kidneys, spleen, joints resulting metastatic abscesses, endocarditis, meningitis, suppurative arthritis
5. Septicemia
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Clinical features
Abrupt onset of high fever with chills Productive cough Mucopurulent sputum Pleuritic pain & friction rub Radiologic appearance
- well circumscribed radio-opacity in LP
- focal opacities in BP
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SUPPURATIVE LUNG DISEASES
Bronchiectasis Lung abscess Empyema
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BRONCHIECTASIS
Definition Disease characterized by permanent
dilatation of bronchi & bronchioles caused by destruction of the muscle & elastic tissue, resulting from or associated with chronic necrotizing infection
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Etiology
Obstruction & infection – major cause
- obstruction (mucus, tumor, FB) → impaired normal clearing mechanism → pooling of secretion distal to obstruction → inflammation of airways
Severe infection → necrotizing fibrosis and eventually dilatation of airways
Dr TTW (2009) 33
Etiology
Congenital or hereditary
- cystic fibrosis
- intralobular sequestration of the lung
- immunodeficiency state
- primary ciliary dyskinesia
- Kartagener syndrome
Dr TTW (2009) 34
Morphology
Lower lobes, bilaterally Vertical air passages Most severe in more distal bronchi &
bronchioles
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Gross
Airways – dilated, up to 4 times Long, tube-like enlargement of airways
→ cylindrical bronchiectasis Fusiform or saccular distension →
saccular bronchiectasis Dilated airways can be followed directly
out to pleural surfaces On C.S → cysts filled with
mucopurulent secretions
Dr TTW (2009) 36
Bronchiectasis
Bronchial tubes are extremely dilated with thicken, fibrotic wall. Adjacent lung is almost completely destroyed
Dr TTW (2009) 37Focal area of dilated bronchi with bronchiectasis.
Dr TTW (2009) 38
Histology
Full-blown, active case → intense acute & chronic inflammatory exudation within the walls of bronchi & bronchioles
Desquamation of lining epithelium Extensive areas of necrotizing
ulceration
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Clinical course
Cor pulmonale Lung abscess Metastatic brain abscesses Amyloidosis
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LUNG ABSCESS
Definition
A local suppurative process within the lung, characterized by necrosis of lung tissue
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Etiology & Pathogenesis
Oropharyngeal surgical procedures, sinobronchial infection, dental sepsis, bronchitis
Aerobic & anaerobic streptococci , Staphylococcus aureus, GN organisms
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Mechanisms
Aspiration of infective material in acute alcoholism, coma, anesthesia, sinusitis, gingivodental sepsis, debilitation - cough reflexes depressed
Antecedent primary bacterial infection - post-pneumonic abscess, fungal infection, bronchiectasis
Septic embolism Neoplasia Miscellaneous
Dr TTW (2009) 43
Morphology
Size -few mm to large cavities of 5-6 cm Single or multiple Abscess due to aspiration → more
common on right ( more vertical right main bronchus ) and more single
Abscess from pneumonia or bronchiectasis → usually multiple, basal, diffusely scattered
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Morphology
Cavity filled with suppurative debris If communication with air passage →
partially drain → air-containing cavity Continued infection → large, fetid,
green-black, multilocular cavities (gangrene of the lung)
Suppurative destruction of lung parenchyma within central area of cavitation
Dr TTW (2009) 45
Seen here are two lung abscesses, one in the upper lobe and one in the lower lobe of this left lung.
Dr TTW (2009) 46abscessing bronchopneumonia in which several abscesses with irregular, rough-surfaced walls are seen within areas of tan consolidation.
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• Old pulmonary abscess cavity. • Multiloculated with delicate strands of fibrous tissue crossing the space. • No evidence of acute inflammation in the wall • Fairly normal surrounding lung.
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Course
Most resolve with antimicrobial therapy Extension of infection into pleural cavity
→ empyema Hemorrhage Septic emboli → brain abscess,
meningitis Secondary amyloidosis
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EMPYEMA
Collection of pus in pleural cavity Suppurative pleuritis Presence of purulent pleural exudates Characterized by loculated, yellow-
green, creamy pus composed of neutrophils admixed with other leukocytes
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Etiology
Contiguous spread of organisms from intrapulmonary infection
Lymphatic dissemination Haematogenous dissemination Direct extension of infection below
diaphragm (subdiaphragmatic or liver abscess) especially on right side
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Clinical course
May resolve by antibiotics
Obliterate pleural space or envelope the lungs → embarrass pulmonary expansion
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