THE LUNG

By Dr Raana Akhtar

PULMONARY INFECTIONS

• URTI• PNEUMONIA Impaired local defence mechanisms. - loss of cough reflex ,defective mucociliary

action,secretions in airways,interference with phagocytosis&pulmonary edema.

Decreased resistance of the host. Chronic diseases,immunologic deficiency,

immunosuppressive agents and leucopenia.

PNEUMONIA

• COMMUNITY ACQUIRED ACUTE PNEUMONIA• COMMUNITY ACQUIRED ATYPICAL PNEUMONIA• HOSPITAL ACQUIRED PNEUMONIA• ASPIRATION PNEUMONIA• CHRONIC PNEUMONIA• NECROTIZING PNEUMONIA &LUNG ABSCESS• PNEUMONIA IN IMMUNOCOMPROMISED HOST

COMMUNITY-ACQUIRED ACUTE PNEUMONIAS

• Streptococcus pnemoniae- gram positive• Haemophilus influenzae-gram negative• Moraxella catarrhalis• Staphlococcus aureus• Klebsiella pneumonia• Pseudomonas aeruginosa• Legionella pneumophila

PNEUMONIA

• MORPHOLOGY• Lobar pneumonia• Bronchopneumonia• Four Stages Of Inflammatory Response CONGESTION RED HEPATIZATION GREY HEPATIZATION RESOLUTION PLEURITIS

SYMPTOMS OF PNEUMONIAS

COMPLICATIONS OF PNEUMONIA

• ABSCESS FORMATION • EMPYEMA• BACTEREMIC DISSEMINATION: Metastatic abscesses,endocarditis,meningitis

and suppurative arthritis.

BRONCHOPNEUMONIA

BRONCHOPNEUMONIA

BRONCHOPNEUMONIA

BRONCHOPNEUMONIA

LOBAR PNEUMONIA

LOBAR PNEUMONIA

COMMUNITY-ACQUIRED ATYPICAL PNEUMONIA

• Mycoplasma pneumoniae• Chlamydia sppc• Coxiella burnetti• Viruses: Respiratory Syncytial virus Parainfluenza virus Influenza A&B Adenovirus SARS virus

COMMUNITY-ACQUIRED ATYPICAL PNEUMONIA

• PATHOGENESIS Attachment of the organism to URT epithelium Necrosis of cells and an Inflammatory response Extends to alveoli,interstitial inflammation Damage to epithelium Inhibit mucociliary clearance Secondary becterial infections

COMMUNITY-ACQUIRED ATYPICAL PNEUMONIA

• Morphology• Patchy or lobar• Unilateral or bilateral• Redblue and congested• Interstitial inflammation within the walls of alveoli• Alveolar septa widened and edematous• Mononuclear infammatory infiltrate of

lymphocytes,macrophages and plasma cells• Intra-alveolar proteinaceous material&cellular exudate

Viral pneumonia with interstitial lymphocytic infiltrate.s

HOSPITAL- ACQUIRED PNEUMONIA

• Enterobacteriaceae• Pseudomonas• S.aureus

ASPIRATION PNEUMONIA

• Unconscious patients• Repeated vomiting• Partly chemical pneumonia(gastric acid)• Bacterial pneumonia(oral flora)• Aerobes and anaerobes• Necrotizing pneumonia• Fulminating clinical course• Lung abscess is a common complication

ASPIRATION PNEUMONIA

ASPIRATION PNEUMONIA

LUNG ABSCESS

• LOCAL SUPPURATIVE PROCESS WITHIN THE LUNG characterized by NECROSIS OF LUNG TISSUE.

• Etiology & Pathogenesis• Streptococci, S.aureus,gram negative

organisms.anaerobic organisms in oral cavity Bacteroides,Fusobacterium and Peptococcus

species in 60% cases.

LUNG ABSCESS

• Aspiration of infective material• Post-pneumonic abscess formatio• Septic embolism• Neoplasia(post-obstructive)• Miscellaneous: spread of infection from neighboring organ, hematogenous seeding • Primary Cryptogenic Lung abscesses

LUNG ABSCESS

• MORPHOLOGY• Few mm to large cavities of 5 to6 cm• Single ,on right side due to aspiration• Multiple,basal due to pneumonia,septic emboli • Suppurative debri in abscess cavity• Continued infection,large greenblack multiloculated cavities

with poorly demarcated margins(gangrene of the lung)• SUPPURATIVE DESTRUCTION OF LUNG PARENCHYMA with

CENTRAL AREA OF CAVITATION• Fibrous wall in chronic cases

LUNG ABSCESS

LUNG ABSCESS

CHRONIC PNEUMONIAS

• Inflammatory reaction is granulomatous caused by

• Bacteria (M.tuberculosis)• Fungi(Histoplasma capsulatum, Blastomyces

dermatitidis, Coccidiodes immitis)

Histoplasmosis

• Histoplasma capsulatum infectionAcquired by inhalation of dust particles from soil

contaminated with bird or bat dropings containing spores

Intracellular parasite of macrophagesApical coin lesions on X-ray chestCough, fever &night sweatsExtrapulmonary localized lesion in

mediastinum,adrenals,liver and meninges

Histoplasmosis

• Macrophages (TNF)• Helper T-cells(INF gamma)• Morphology Epitheloid cell granulomata with caseous necrosis Large areas of consolidation may liquify to form cavitiesLesions undergo fibrosis and concentric calcification(tree-bark

appearance)3 to 5 micron meter thin walled yeast may persist in tissues for

years.Fulminating Disseminated Histoplasmosis. Macrophages filled

with fungal yeast.

BLASTOMYCOSIS

• Blastomyces dermatitidis• Pulmonary,Disseminted& Primary cutaneousConsolidation ,multilobar infiltrates,perihilar

infiltrates or miliary infiltrates.Suppurative granulomas5 to15-micron meter yeast cells

Coccidioidomycosis

• Inhalation of spores of Coccidioides immitis• Lung lesions in 10%. • Granulomatous lesions• Nonbudding sperules filled with small

endospores within macrophages and giant cells

Chronic abscessing inflammation

TB LUNG

Pulmonary disease in HIV infection

Pneumocystis carinii jirovesi