What is Lobar Pneumonia ?

Lobar Pneumonia Definition

lobar pneumonia refers to consolidation of an entire lobe while bronchopneumonia is scattered solid foci in the same or several lobes.

Causative Agent:

  • Pneumococci (Streptococci pneumoniae I, II, III, IV types)
  • Klebsiella pneumoniae

Pathogenesis of Lobar Pneumonia

  • Preceding sensibilisation to microbial agent.
  • Triggering factor such as hypothermia, trauma etc

Signs and Symptoms:

  • High fever
  • Chills
  • Shortness of breath
  • Increased breathing rate ( Tachypnoea)
  • A worsening cough that may produce discoloured or bloody sputum (phlegm)
  • Sharp chest pains – caused by inflammation of the membrane that lines the lungs.(pleuritis)

Affected Lobes in Lobar Pneumonia

1 lobe (right lower is most common), 2 lobes, 3 lobes

lobar Pneumonia helpmedico

Stages of Lobar Pneumonia

 

  • Consolidation

    • Occurs in the first 24 hours
    • Cellular exudates containing neutrophils, lymphocytes and fibrin replaces the alveolar air
    • Capillaries in the surrounding alveolar walls become congested
    • The infections spreads to the hilum and pleura fairly rapidly
    • Pleurisy occurs
    • Marked by coughing and deep breathing (Atkuri & King, 2006; Steyl, 2007

 

  • Red Hepatization

    • Occurs in the 2-3 days after consolidation
    • At this point the consistency of the lungs resembles that of the liver
    • The lungs become hyperaemic
    • Alveolar capillaries are engorged with blood
    • Fibrinous exudates fill the alveoli
    • This stage is “characterized by the presence of many erythrocytes, neutrophils, desquamated epithelial cells, and fibrin within the alveoli”

 

  • Grey Hepatization

    • Occurs in the 2-3 days after Red Hepatization
    • This is an avascular stage
    • The lung appears “gray-brown to yellow because of fibrinopurulent exudates, disintegration of red cells, and hemosiderin”
    • The pressure of the exudates in the alveoli causes compression of the capillaries
    • “Leukocytes migrate into the congested alveoli”

 

  • Resolution

    • This stage is characterized by the “resorption and restoration of the pulmonary architecture”
    • A large number of macrophages enter the alveolar spaces
    • Phagocytosis of the bacteria-laden leucocytes occurs
    • “Consolidation tissue re-aerates and the fluid infiltrate causes sputum”
    • “Fibrinous inflammation may extend to and across the pleural space, causing a rub heard by auscultation, and it may lead to resolution or to organization and pleural adhesions”

 

Complications

  • Pleuritis, often painful, is common, because the pneumonia readily extends to the pleura
  • pleura is usually involved; sometimes “lobar pneumonia” is called “pleuropneumonia”
  • Pleural effusion occurs frequently, but usually resolves
  • Pyothorax results from infection of a pleural effusion, and may heal with extensive fibrosis
  • Pulmonary fibrosis. The intra-alveolar exudate organizes to form intra-alveolar plugs of granulation tissue. Gradually, increasing alveolar fibrosis leads to a shrunken and firm lobe, a rare complication known as carnification
  • Lung abscess due to destruction of lung tissue by enzymes of leucocytes and macrophages. A cavity is formed filled with pus and surrounded by fibrous tissue.
  • Gangrene due to necrosis of lung tissue.
  • Dark coloration is due to liberation of hemoglobin from hemolyzed red blood cells, which is acted upon by hydrogen sulfide (H2 S), resulting in formation of black iron sulfide that remains in the tissues.
  • Spreading of the infection:

Hematogenous: bacteremia occurs in the early stages of pneumococcal pneumonia in more than 25% of patients, and may lead to endocarditis, meningitis, brain abscess, arthritis or sepsis.
Lymphogenous: pericarditis and mediastinitis

 

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Investigations

  • Physical examination
    • Auscultation- Bronchial breath sounds or fine cracks over the affected area
    • ? Pleural rub
  • Chest X-ray
    • usually done to confirm the diagnosis
  • Sputum samples and blood tests
    • done to diagnose the type of pneumonia that is present
    • sputum test is done to determine whether it is a fungal or bacterial infection
    • blood test is done to examine the White Blood Cell count of the involved patient
    • this can be used to indicate the severity of the pneumonia, as well as to determine whether it is a viral or bacterial infection.
    • bacterial infection would result in a blood count that has an increased amount of neutrophils
    • a blood count that has an increased amount of lymphocytes would indicate a viral infection.
    • Increased CRP

 

Treatment

  • Antibiotics – given by mouth as tablets or liquid
  • Pain relieving medications
  • Paracetamol to reduce fever
  • Rest.

If treatment in hospital is required, treatment usually includes:

  • Antibiotics given intravenously (via a drip into a vein)
  • Oxygen therapy – to ensure the body gets the oxygen it needs
  • Intravenous fluids – to correct dehydration or if the person is too unwell to eat or drink
  • Physiotherapy – to help clear the sputum from the lungs.

 

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