4 Consolidation of the lung occurs in pneumonia What is consolidation?Consolidation is exudative solidification of lung parenchyma that occurs in bacterial invasion of the lung.This is known as pneumonia.
5 Defense mechanisms of the respiratory tree: Nasal clearance: Aerosolized particles carrying micro-organisms are normally removed by sneezing & blowing OR by swallowing.Tracheobronchial clearance: Accomplished by mucociliary action. Partcicles are either swallowed or expectorated.Alveolar clearance: Phagocytosis of bacteria or solid particles by alveolar macrophages.
6 Pneumonia can occur when any of these mechanisms are damaged ORWhen host immunity is lowered.When the organism is highly virulent.
7 Factors that interfere with defense mechanisms: Loss or suppression of cough reflex: Coma, general anaesthesia, neuromuscular disorders, drugs & chest pain.Injury to mucociliary apparatus: Smoking, corrosive gases, viral diseases, genetic (immotile cilia syndrome).Impaired phagocytic clearance: Alcoholism, cigarette smoke, anoxia, oxygen intoxication.Pulmonary congestion & oedema.Accumulation of secretions: Cystic fibrosis
24 Bronchopneumonia (patchy) Extremes of age. (infancy and old age)Staph, Strep, Pneumo & H. influenzaPatchy consolidation – not limited to lobes.Suppurative inflammationUsually bilateralLower lobes common
31 Broncho – Pneumonia - Lobar Extremes of age.Secondary to other disorders.Staph, Strep, H.influenzaePatchy consolidationAround Small airwayNot limited by anatomic boundaries.Usually bilateral.Middle age – 20-50Primary in a healthymales common.95% pneumoc (Klebs.)Entire lobe consolidationDiffuseLimited by anatomic boundaries.Usually unilateral
33 Interstitial / atypical Pneumonia Primary atypical pneumonia in the immunocompetant host (Mycoplasma or Chlamydia)Interstitial pneumonitisimmunocompromised host : Pneumocystic carinii; CMVImmunocompetant host: Influenza AGross features:Lungs are heavy but not firmly consolidatedMicroscopic features:Septal mononuclear infiltrateAlveolar air spaces either ‘empty’ or filled with proteinaceous fluid with few or no inflammatory cells
35 Interstitial Pneumonia: Lymphocyte Infiltrate in alveloar wall
36 Etiologic agents Distribution Microscopic features Lobar pneumonia Broncho pneumoniaAtypical (interstitial pneumonia)Age groupAny age groupInfancy & old age commonPredisposing factorsHighly virulent organismsCCF, disseminated malignancy, pre-existing bronchitis, bronchiolitisMalnutrition, alcoholism, underlying debilitating illnessesEtiologic agents90-95% of cases caused by pneumococci(Strep.pneumoniae)StaphylococciStreptococciPneumococciH. InfluenzaePseudomonas aeruginosaColiform bacteriaMycoplasma pneumoniaeChlamydiaCoxiella burnettiDistributionConsolidation of large areas of one lobe or the whole lobePatchy consolidation of more than one lobe of the lungInvolvement maybe patchy or involve whole lobes unilaterally or bilaterallyMicroscopic featuresInvolvement of all alveoli of one lobe by inflammatory exudate;The 4 classical stages of consolidation are best seen in lobar pneumoniaPatchy involvement of alveoli around the bronchioles in more than one lobe by inflammatory exudateInterstitial inflammation composed of lymphocytes, virtually localized within alveolar walls
37 Community acquired – Pneumonia – Nosocomial In healthy adultsGram positive.Streptococcus pneumoniae (90%)Strep. Pyogenes, Staph, H. influenzae and Klebsiella in elderly or with COPD.In *sick patients.gram-negative bacilliPseudomonas aeruginosa, Escherichia coli, Enterobacter, Proteus, and Klebsiella.
39 Complications of Pneumonia AbscessesLocalized suppurative necrosis, Right side often involved in aspiration.Common etiologic agents are Staphylococcus, Klebsiella, PneudomonasPleuritis / Pleural effusion.Inflammation of the pleura ( Streptococcus pneumoniae)Blood rich exudate (esp. rickettsial diseases)EmpyemaPus in the pleural space.Septicemia: with bacteremic dissemination to heart valves, pericardium, brain, spleen, kidneys or joints causing metastatic abscesses, endocarditis, meningitis or suppurative arthritis.Organization of the exudate resulting in fibrosis.