Lobar pneumonia Vs Bronchopneumonia

Lobar pneumonia:

• Usually caused by Streptococcus pneumoniae, although other organisms can cause this disease (e.g. Klebsiella pneumoniae)

• Involves a large portion of or an entire lobe of lung

• Typically affects young healthy adults and is thus a primary pneumonia

The following sequence of stages is classic but infrequently seen because of antibiotic therapy. The various stages portray the natural history of uncomplicated lobar pneumonia:

1. Congestion: of alveolar vessels; fluid exudate moves into the alveolar spaces ( organisms)

2. Red hepatisation: (consolidation) describes lung tissue with confluent acute exudation, containing neutrophils and red cells, giving a red, firm, liver-like gross appearance.

3. Grey hepatisation: follows, as the red cells disintegrate and the remaining fibrinosuppurative exudate persists, giving a grey-brown appearance.

4. Resolution: is the favourable final stage in which consolidated exudate undergoes enzymatic and cellular degradation and clearance; normal structure is restored.

Clinically the patient may have:

• Severe fever with rigors or shivering attacks

• Cough with ‘rusty’ blood-stained sputum (red hepatisation)

• Difficulty breathing

• Pleurisy; characterized by sharp pain on coughing or on deep inspiration and pleural friction rub

Bronchopneumonia:

• Caused by a wider variety of organisms (most commonly Staphylococci, also Streptococci, H. influenzae, P. aeruginosa, coliforms and some fungi)

• Initially infection is centred on bronchi and surround alveoli (lobular), although if untreated it can spread to become lobar.

• Tends to occur at the extremes of life or in those suffering from other illnesses (e.g. cancer, heart failure, renal failure, stroke, airways diseases etc.) – thus generally a secondary type of pneumonia

Grossly the lungs show dispersed (often in basal areas of both lungs) focal (patchy) areas of consolidated acute inflammation.

Histologic features consist of an acute (neutrophilic) suppurative exudate filling airspaces and airways, usually about bronchi and bronchioles.

Resolution of the exudate usually restores normal lung structure, but organization may occur and result in fibrous scarring (healing by fibrosis).

Clinically the patient may have:

• Septicaemia with high temperature

• Crackles (crepitations) on auscultation of affected areas

Category: Medicine Notes