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PATHOLOGY PRACTICAL

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•LOBAR PNEUMONIA•BRONCHIECTASIS

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 1.COMMUNITY-ACQUIRED BACTERIAL ACUTE PNEUMONIAS (BACTERIAL)Streptococcus PneumoniaHaemophilus InfluenzaeMoraxella CatarrhalisStaphylococcus AureusKlebsiella PneumoniaePseudomonas AeruginosaLegionella Pneumophila

2.COMMUNITY-ACQUIRED ATYPICAL (VIRAL AND MYCOPLASMAL) PNEUMONIAS (NON-BACTERIAL)

Influenza InfectionsSevere Acute Respiratory Syndrome (SARS)

3.NOSOCOMIAL PNEUMONIA4.ASPIRATION PNEUMONIA5.LUNG ABSCESS

6.CHRONIC PNEUMONIAHistoplasmosis, MorphologyBlastomycosis, MorphologyCoccidioidomycosis, Morphology

7.PNEUMONIA IN THE IMMUNOCOMPROMISED HOST8.PULMONARY DISEASE IN HUMAN IMMUNODEFICIENCY VIRUS INFECTION

PULMONARY INFECTIONS

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NORMAL

CXR

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• The specimen is a slice of the left lung.• The upper lobe is relatively normal, except

for an old scar near the apex of the lung caused by tuberculosis.

• The major abnormality is that the lower lobe is uniformly consolidated (airless and solid) due to lobar pneumonia, with inflammatory cells and exuded plasma filling the airspaces.

• The shaggy material on the pleural surface is fibrin, a protein derived from fibrinogen in exuded plasma.

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• Microscopic Appearances:

• Sections through the lower lobe show dilated, congested blood vessels in the alveolar walls.

• The alveolar spaces are filled with inflammatory cells, mainly neutrophils, and inflammatory exudate, including fibrin.

• There are large aggregates of fibrin on the pleural surface.

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• Pneumonia is an acute inflammation of the airspaces of the lung, usually caused by bacterial infection.

• This woman died of pneumonia affecting an entire lobe of the lung, before the advent of antibiotics.

• Nowadays, it is uncommon to die in the acute stages of lobar pneumonia because Streptococcuspneumoniae ("the pneumococcal"), which is the bacterium that typically causes a lobar distribution of pneumonia, is sensitive to various antibiotics.

• However, there is an increasing incidence of pneumococcal resistance to Penicillin - usually the most effective antibiotic in this situation.

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VIRAL PNEUMONIAS• Frequently “interstitial”, NOT alveolar

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BRONCHIECTASIS

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Definition • Abnormal and irreversible dilatation of bronchi

and bronchioles greater than 2.m.m. in diameter developing secondary to inflammatory weakening of the bronchial walls.

• Persistent cough with expectoration of copious amounts of foul smelling purulent sputum.

• Post infectious cases commonly develop in childhood and early adult life.

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Aetiology

• Hereditary and congenital factors• End bronchial obstruction• Infections.

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Infections-Micro-organisms

• Measles and Pertussis• Adeno & Influenza virus• Bacterial infection with virulent

organisms: S.aureus, Klebsiella Anaerobes

• Atypical mycobacteria• Mycoplasma• HIV• Tuberculosis• Fungi

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IMPAIRED HOST DEFENCE

• Local causes: End bronchial obstruction• Generalized impairment:

1. Immunoglobulin deficiency

2. Primary ciliary disorders

3. Cystic fibrosis

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• Persistent or recurrent cough with purulent sputum.

• Hemoptysis• Initiating episode: Severe pneumonia, or

insidious onset of symptoms or asymptomatic or non-productive cough – dry bronchiectasis in upper lobe,

• Dyspnoea, wheezing – widespread bronchiectasis or underlying COPD.

• Exacerbation of infection: Sputum volume increase, purulence or blood.

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DIAGNOSIS

• Clinical• Radiology: Chest XR: May be non-specific

mild disease – normal XRC advanced disease – cysts + fluid levelsperibronchial thickening, “tram tracks”, “ring shadows”

CT Scan: Peribronchial thickening, dilated bronchioles.

• Sputum culture: Pseudomonas aeuruginosa, H.influenzae.

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