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Respiratory III. Dr Basu MD. Part I. Bacterial Pneumonia Community-Acquired Atypical Pneumonia Lung Abscess. Part II. Tuberculosis . Part I. Bacterial Pneumonia : general features. Definition of Pneumonia: Consolidation of lung Inflammation by infective agents.
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Respiratory III Dr Basu MD
Part I • Bacterial Pneumonia • Community-Acquired Atypical Pneumonia • Lung Abscess
Part II • Tuberculosis
Bacterial Pneumonia : general features • Definition of Pneumonia: • Consolidation of lung • Inflammation by infective agents. • Morphological types of Bacterial pneumonia: • Lobar pneumonia • Bronchopneumonia
Lobar pneumonia: acute pneumonia • Agent: Streptococcus pneumoniae, or pneumococcus ( diplococcic), kelbsiella. • Age : elderly, malnourished, debilitated person. • Features: • involve the entire lobe • Formation of intra alveolar exudates ( plenty ).
Bacterial Pneumonia Streptococcus pneumoniae, or pneumococcus
Lobar pneumonia • 4 morphological stages (seen if no antibiotic is used): • Congestion. • Red hepatization (consistency like liver, red due to RBC). • Gray hepatization ( consistency like liver. Gray due to exudates in alveolus). • Complete Resolution ( complete restoration of normal histology of lung).
This is a : Lobar pneumonia: locate the area
Streptococcus Pneumoniae Pneumonia An entire love is involved. All Neutrophils in alveolous.
Broncho-pneumonia. • Patchy • Age: extreme age group ( very old and child) • Organism: Staphylococcous aureas, H. influenzae, K.Pneumoniae, streptocossous pyogens. • Infection spread from bronchi to adjacent alveoli.
Broncho-pneumonia Patchy bronchopneumonia with areas of tan-yellow consolidation.
Bronchopneumonia: Patchy area of alveoli that are filled with PMNs AND EXTEDED INTO ADJACENT BRONCHI.
Complication of pneumonia • Abscess formation. • Pleural empyema • Sepsis→ ARDS • Fibrous pleural scar, Organized pneumonia. Alveolar fibrosis: Organized pneumonia ( lung become solid)
Clinical course • High fever • Chest pain • Cough productive of mucopurulent sputum ( rust color ..if blood present)
Community-Acquired Atypical Pneumonias • Other name:Interstitial pneumonia. • Age: children and young adult. • Clinical Presentation is different from typical bacterial pneumonia: • Cough with no or mild to moderate sputum production. • No physical finding of consolidation.
Community-Acquired Atypical Pneumonias • Agents: • Chlamydia, Mycoplasma, virus • Viruses: • Respiratory syncytial virus, • parainfluenza virus (children); • influenza A and B (adults); • adenovirus (military recruits); • SARS* virus
Common morphology of all Acquired Atypical Pneumonias • The interstitium in the alveolar wall is the main location of inflammation ( lymphocytes and plasma cells) with or without an intra-alveolar exudate.
Mycoplasma pneumonia (most common form of ATYPICAL PNEUMONIA) • Cause: Mycoplasma infection. • Lab: Elevation of titers of cold agglutinins (IgM) in Mycoplasmal infection (in 50% of cases). • PCR for mycoplasma DNA is available.
lymphocytes and plasma cells in interstitial area and no exudates in the alveolar space Mycoplasma pneumonia
Lung Abscess • Definition: localized collection of Neutrophils and necrotic lung tissue. • Cause: • Bronchiectasis • Aspiration of gastric content • Bacterial pneumonia- septic emboli. • Risk group: • Loss of consciousness ( drug, alcohol) • General anesthesia • Bad oral/dental hygiene
Lung Abscess • Anaerobic / Aerobic bacteria : etiology is oral cavity disease. • Aerobic organisms frequently isolated: • Staphylococcous aureus, β hemolytic streptococci = Pneumonia. • Pseudomonas, Kelbsiella = Pneumonia.
Morphology of Lung Abscess • Location: • Aspiration abscess: • Right > left lung. • Pneumonia or bronchiectasis abscesses: • Basal. • X- ray : air fluid level
Lung Abscess : x ray : ‘air fluid level’ Lung abscess: liquefactive necrosis
Clinical course of Lung Abscess • Cough copious amounts of foul-smelling, purulent sputum. • Striking fever.
Tuberculosis • Definition of tuberculosis: • Communicable Granulomatous disease caused by Mycobacterium Tuberculosis. • [M. avium-intracellulare 10-30% of patients with AIDS]
TuberculosisEpidemiology • TB in the US is a disease of: • The elderly. • The urban poor. • The immuno-suppressed (AIDS).
TuberculosisEpidemiology • Certain disease states increase the risk. • Diabetes mellitus, silicosis, • Malnutrition or Alcoholism. • Immunouppression (HIV).
Type of tuberculosis • Primary • Lung • Lymph nodes (cervical) • GIT • Secondary
Pathogenesis of granuloma formation APC activated CD4 cells through MHC II and TCR complex CD4 APC Activated CD4 cell produce INF-gamma Modify (activate) the macrophage = epitheloid cells Collection of many epitheloid cells= Granuloma Activated macrophage kill bacteria by NO Caseation necrosis
Primary tuberculosis • Definition of primary tuberculosis: • The disease that develop in a previously unexposed (unsensitized) persons. • Morphology: Ghon complex • Focus of primary TB: Lung, Intestine, lympnnodes (Cervical LN).
The Ghon complex: subpleural granuloma + marked hilar lymphadenopathy. Most often in children. .
Primary Tuberculosis: Caseating granuloma with Langhans giant cells: this may calcify.
Implications of Primary Tuberculosis • It may resolve • It may progress to progressive primary tuberculosis. • Some bacilli harbor in the apex of lung for survival (due to high Oxygen level).
Secondary TB • DEF: disease that arises in a previously sensitized host . • Type: • Reactivation of dormant primary lesions. • Exogenous re-infection.
Secondary Tuberculosis (location) • Location of lesions: classically localized to the apex of one or both upper lobes.
Pattern of Secondary Tuberculosis Early lesion Small focus of consolidation Near the apical pleura
Progressive pulmonary tuberculosis • Seen in the elderly and immunosuppressed. Both lung involved with cavitary lesion. • This may progress to spread to various organs.
Progression of Sec. progressive TB Erosion of Bronchus, lymphatic or blood vessels by granuloma Release of caseation in bronchus Lymphatic spread: pulmonary miliary TB Spread by Blood vessels: systemic miliary TB and hemoptysis Seeding to trachea and bronchus
Miliary pulmonary tuberculosisCaseating granuloma : size of Millet seeds.
Clinical Course of Tuberculosis • Low grade fever (remitting). • Night sweats. • Malaise. • Anorexia. • Weight loss.
Clinical Course of Tuberculosis • Diagnosis: • Acid-fast smears and culture of the sputum. • PCR amplification of M. tuberculosis.
TuberculosisMantoux skin testing • False negative (skin test anergy) maybe produced by: • Sarcoidosis. • Immunosuppression. • Overwhelming active tuberculosis. • Hodgkin disease. • False positive results atypical mycobacterium.
Nontuberculous Mycobacterial Disease • Stains implicated in the US are: • M. avium-intracellulare. • M. Kansasii. • M. abscessus. • Can mimic typical tuberculosis in presentation upper lobe cavitary disease.