ACUTE BACTERIAL PNEUMONIA

DEFINE

Characterized=consolidation due to exudate

A.I caused by micro-organisms

AETIOLOGY

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Lobular/Bronchopnemonia

• Infection of terminal bronchioles>alveoli>patchy grey/ red consolidation of lung

• Multilobular and bilateral and basal>secretion>↑ in lower zones

• Patchy areas of inflammation begin as bronchitis & bronchiolitis

• Focal areas develop within acini

• Infection localised by rapid neutrophil response in alveoli & bronchioles

• Organisms>in small bronchioles VIA aspiration of purulent fluid/penetrating inflamed bronchiolar walls>surrounding walls

• Healing by fibrosis

Predisposing factors>

previous acute infections such as influenza, measles, pertussis, & mycoplasma bronchitis , cystic fibrosis

 chronic lung diseases such as chronic bronchitis

aspiration of food, vomit or irritant gases

obstructed bronchus due to foreign body/mucus

 post-surgery

 carcinoma

LOBAR

Diffuse fibrinosuppurative consolidation of large portion /whole lobe

• Spread limited by a fissure or pleura>segmental/lobar distribution

Chronic bronchitis>S. pneum. , H. influenzae

Cystic fibrosis>S.aures,H.influenzae,Pseudomonas

Viral complication>S.aureus , S.pneumonia

Immunosuppressision>S.pneum., S. Aureus, Pseudomonas,Anaerobes,Klebsiella

Prev. healthy>Strep.Pneumoniae

Bronchial tumor>S.pneum. ,S.aureus , Anaerobes

Aspiration>Anaerobes

Pneumococcal

Morphology>nose(commensal)>inhaled into lung>lodges in alveoli>outpouring of edema fluid>due to hypersensitivity

Bacteriology: Gram +ve diplococcus, type 1-3(lobar) , an type(bronchopneumonia)

4 stages

Incidence:50% of L.P Sex:males, Age:30-50,Season:Winter& early spring,Mortality:40%(without treatment)

Red Hepatisation(2-4)

Grey Hepatization(2-3)

Acute congestion(1-2 Days)

Resolution(8TH DAY-Many wks)

Complications

Local: emphysema, lung abscess, bronchiectasis, cornification

Dissemination>A. pneumococcal bronchitis, foci of bronchopneumonia, bacteriamia/ septicaemia, acute endocarditis

Lobular Microscopically

  1. Acute bronchiolitis

• 2. Infiltration by neutrophils in bronchi and bronchioles.

• 3. Thickening of alveolar septa

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spread of infected edema through pores of Kohn

4 stages