Pulmonary Infections

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First step to make your dreams come true is
to... wake up! Paul Valery
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Pathology of Pneumonia

• Dr. Venkatesh M. Shashidhar
• Associate Professor of Pathology
• Fiji School of Medicine

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Introduction

• 5000 sq meters of area.! (olympic track)
• Filters 10,000 L of air / day!
• Normal lungs are sterile.
• Delicate, thin resp. mem gas exch.
• Filter, humidify, sterilize, highly sensitive.
• RTI Resp. tract inf. commonest in medical
  practice.
• Enormous morbidity mortality.
• Pneumonia inflammation of alveoli.

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Normal Lung
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Normal Lung
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Etiology

• Decreased resistance - General/immune
• Virulent infection - Lobar pneumonia
• Defective Clearing mechanism
• Cough/gag Reflex Coma, paralysis, sick.
• Mucosal Injury smoking, toxin aspiration
• Low Alveolar defense - Immunodeficiency
• Pulmonary edema Cardiac failure, embol.
• Obstructions foreign body, tumors

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Patterns of Lung disorders

• Airway
• Bronchitis, Bronchiectasis, Bronchiolitis.
• Tumors / Cancer
• Parenchyma
• Pneumonia.
• Lung abscess, TB
• Hyaline membrane dis (HMD ARDS)
• Pneumoconiosis
• Tumors / Cancer
• Pleura
• Pleural effusion (TB)
• Tumors / Cancer

Infections
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Pathogenesis of Pulmonary Infections

• Step 1 Entry
• Aspiration (ie Pneumococcus)
• Inhalation (ie Mtb and viral pathogens)
• Inoculation (contaminated equipment)
• Colonization (in patients with COPD)
• Hematogenous spread (patients with sepsis)
• Direct spread (adjacent abscess)

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Pathogenesis
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Pathogenesis
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Pneumonia Types

• Etiologic Types
• Infective
• Viral
• Bacterial
• Fungal
• Tuberculosis
• Non Infective
• Toxins
• chemical
• Aspiration

• Morphologic types
• Lobar
• Broncho
• Interstitial
• Duration
• Acute
• Chronic
• Clinical
• Primary / secondary.
• Typical / Atypical
• Community a / hospital a

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Lobar Pneumonia

• whole lobe, exudation - consolidation
• 95 - Strep pneum.(Klebsiella in aged, DM,
  alcoholics)
• High fever, rusty sputum, Pleuritic chest pain.
• Four stages (also in bronchopneumonia)
• Congestion 1d vasodilatation congestion.
• Red Hepatization 2d ExudationRBC
• Gray Hepatizaiton 4d neutro Macrophages.
• Resolution 8d few macrophages, normal.

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Pathogenesis of Pneumonia
Grey Hepatization Resolution
Congestion Red Hepatisation
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Lobar Pneumonia
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Lobar Pneumonia
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Lobar Pneumonia Gray hep
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Lobar Pneumonia
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Lobar Pneumonia Congestion
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Lobar Pneumonia Red hepat.
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Lobar Pneumonia Grey hepat.
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Broncho-pneumonia
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Bronchopneumonia (patchy)

• Extremes of age. (infancy and old age)
• Staph, Strep, Pneumo H. influenza
• Patchy consolidation not limited to lobes.
• Suppurative inflammation
• Usually bilateral
• Lower lobes common

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Broncho-pneumonia
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Broncho-pneumonia
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Broncho Pneumonia
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Bronchopneumonia
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Bronchopneumonia - CT
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Bronchopneumonia
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Broncho Pneumonia - Lobar

• Extremes of age.
• Secondary.
• Both genders.
• Staph, Strep, H.infl.
• Patchy consolidation
• Around Small airway
• Not limited by anatomic boundaries.
• Usually bilateral.

• Middle age 20-50
• Primary in a healthy
• males common.
• 95 pneumoc (Klebs.)
• Entire lobe consolidation
• Diffuse
• Limited by anatomic boundaries.
• Usually unilateral

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Broncho Pneumonia - Lobar
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Interstitial / atypical Pneumonia

• Primary atypical pneumonia in the immunocompetant
  host (Mycoplasma or Chlamydia)
• Interstitial pneumonitis
• immunocompromised host Pneumocystic carinii
  CMV
• Immunocompetant host Influenza A
• Gross features
• Lungs are heavy but not firmly consolidated
• Microscopic features
• Septal mononuclear infiltrate
• Alveolar air spaces either empty or filled with
  proteinaceous fluid with few or no inflammatory
  cells

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Interstitial Pneumonia
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Interstitial Pneumonia
Lymphocyte Infiltrate in alveloar wall
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Chronic Pneumonia

• Chronic, lymphoid infiltrate,
• No classic stages.
• Lung destruction cavity, abscess etc.
• Organisms
• Mycobacterium tuberculosis
• Histoplasma capsulatum
• Aspergillosis
• Actinomyces

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Comm Pneumonia - Nosoc

• In healthy adults
• Gram positive.
• Streptococcus pneumoniae (90)
• Strep. Pyogenes, Staph, H. influenzae and
  Klebsiella in elderly or with COPD.

• In sick patients.
• gram-negative bacilli
• Pseudomonas aeruginosa, Escherichia coli,
  Enterobacter, Proteus, and Klebsiella.

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Pathogenesis of Clinical features

• Alveolar inflammation.
• Tachypnoea, Dyspnoea, Resp Acidosis ?
  Solid/airless lungs decreased oxygenation.
• Dull percussion - Consolidation Exudation
• Rusty sputum - RBC Inflammatory cells.
• Fever Inflammatory mediators.

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Complications of Pneumonia

• Abscesses
• Localized suppurative necrosis, Right side often
  in aspiration.
• Staphylococcus Klebsiella Pneudomonas
• Pleuritis / Pleural effusion.
• Inflammation of the pleura ( Streptococcus
  pneumoniae)
• Blood rich exudate (esp. rickettsial diseases)
• Empyema
• Pus in the pleural space.
• Septicemia

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Abscess formation
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Lung Abscess
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Abscess formation
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Lung Abscess
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Lung Fungal Abscess Candida
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The only place where success comes before work
is in a dictionary!Vidal Sassoon
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