3. INTRODUCTION
• Acute & Chronic pulmonary infections are
common at all ages and are frequently cause
of death.
• They are generally caused by a wide variety of
microorganisms such as ……
• a. Bacteria
• b. Viruses
• C. fungi and Mycoplasma
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11. DEFINITION
• Pneumonia is defined as acute inflammation
of the lung parenchyma distal to the terminal
bronchioles .
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12. • The term “Pneumonia” and “ Pneumonitis”
are often used synonymously for
inflammation of the lungs.
Consolidation : Meaning solidification is the
term used for gross and radiologic appearance
of the lungs in pneumonia.
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13. CLASSIFICATION OF PNEUMONIA
• On the basis of the anatomic part of the lung
parenchyma involved, pneumonias are
traditionally classified as………..
• 1. Anatomical Classification
• 2.Etiological Classification
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14. 1 : Anatomical classification.
• A – lobar pneumonia .
• The consolidation involves all or part of lobe
• B – Bronchopneumonia
• the consolidation involves scattered lobules
• C - Interstitial pneumonia .
• As in viral pneumonia where inflammatory .
• Infiltrate involve mainly interstitial tissue
between alveoli.
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21. PATHOGENESIS
• The microorganisms gain entry into the lungs
by one of the following four routes.
• 1.Inhalation of microbes present in the air
• 2. Aspiration of organisms from the
nasopharynx or oropharynx.
• 3.Haematogenous spread from adjoining site
of infection.
• 4. Direct spread from an adjoining site of
infection.
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22. Conti……….
• The lower respiratory tract is normally sterile by
• -Physiologic defense mechanisms including
• -Mucociliary clearance
• -Properties of normal secretion such as secretory
immunoglobulin A IgA
• - Clearing of air way by coughing
• Immunologic defense mechanism of lung limit invasion
by pathogenic organisms
• Includes macrophages are present in alveoli and
bronchioles secretory IgA and others immunoglobulins
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23. • Failure of these defense mechanisms and presence of
certain predisposing factors result in pneumonias.
• These conditions are as under.
• 1. Altered consciousness . Eg: CVA, Cranial Trauma.
• 2.Depressed cough and glottic reflexes . Eg. Old age ,
pain from trauma.
• 3.Impaired Mucociliary transport.
• 4.Impaired alveolar macrophage function
• 5.Endobronchial Obstruction.
• 6.Leukocyte dysfunction.
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24. BACTERIAL PNEUMONIA
• Bacterial infection of the lung parenchyma is
the most common cause of the pneumonia
• or
• Consolidation of one or both the lungs .
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25. • Two types of bacterial pneumonias are
distinguished
• - Lobar pneumonia
• Broncho ( Lobar ) Pneumonia …… each with
different etiological agent and morphological
changes.
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26. • Another type distinguished by some workers
separately is confluent pneumonia involves
larger areas in both the lungs irregularly ,
while others consider this as a variant of
bronchopneumonia.
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27. Lobar pneumonia
• Lobar pneumonia is an acute bacterial
infection of a part of a lobe or even two lobes
of the lungs
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28. ETIOLOGY
• Based on the etiologic microbial agent causing
lobar pneumonia, following types of lobar
pneumonia are described
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30. MORPHOLOGICAL FEATURES
• Laennec’s original description divide lobar
pneumonia into 4 sequential pathologic
phases….
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31. • 1.Stage of congestion( initial Phase )
• 2. Red Hepatisation ( Early consolidation )
• 3. Grey Hepatisation (Late consolidation)
• 4.Resolution
• However these classic stages seen in untreated
cases are found much less often nowadays due to
early institiution of antibiotic therapy.
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32. • In lobar pneumonia as the name suggest, part
of a lobe , a whole lobe, or two lobes are
involved, some times bilaterally.
• The lower lobes are affected most commonly.
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33. 1. Stage of congestion initial phase
• The initial phase represents the early acute
inflammatory response to bacterial infection
and lasts for 1 -2 days
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34. • Gross Examination :
• - The affected lobe is enlarged
• - Heavy
• - Dark red
• - Congested .
• _ Cut surface exudes blood –stained frothy
fluid.
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