PneumoniaPneumoniaByBy

Dr. Abdelaty ShawkyDr. Abdelaty ShawkyAssistant professor of pathologyAssistant professor of pathology

PNEUMONITIS

* Classification:1. Bacterial pneumonia: lobar pneumonia & bronchopneumonia.

2. Viral (interstitial) pneumonia: influenza, measles, chicken pox.

3. Loeffler’s (parasitic) pneumonia: Bilharziasis, ascaris &

ankylostomiasis.

4. Granulomatous pneumonia: T.B, sarcoidosis, leprosy, syphilis,

actinomycosis .

5. Lipoid pneumonia: due to aspiration of oily nasal drops.

6. Irradiation pneumonia.

LOBAR PNEUMONIALOBAR PNEUMONIA

* Def: acute diffuse fibrinous inflammation of one or

more lung lobes.

* Etiology:

• Age: middle age.

• Predisposing factors: low resistance.

• Causative organism: pneumococci.

• Route of infection: droplet infection.

* Pathogenesis:• Pneumococci are inhaled to reach alveoli.

They cause acute inflammaion with excess fluid exudate. This fluid exudate pass from one alveolus to another rapidly through the inter- alveolar pores of cohn to involve the whole lung lobe. The fluid exudate expel air away from the alveoli producing a firm airless lobe leading to consolidation (hepatisation) of the affected lobe.

1 .Stage of congestion 2 .Stage of red hepatization

3 .Stage of gray hepatization

4 .Stage of resolution

1. Duration 1st day 2nd – 4th day 5th – 8th day 9th – day 21

2. Gross Picture: the affected lobe is

- Size: Enlarged.- Color: Red.- Consistency: like wet sponge.

- Cut section: exudes

frothy fluid.- The covering pleura: normal

- The hilar L.Ns.: normal

- Enlarged.- Red.- Consistency: consolidated (hepatized).- Cut section: dry.- Pleurisy.- Enlarged hilar LNs.

- Enlarghed.- Gray.- Consistency: consolidated (hepatized).- Cut section: dry.- Pleurisy.

- Enlarged hilar

LNs.

- Since there is no necrosis, healing by resolution occurs.

Lobar pneumonia of Lobar pneumonia of upper lobeupper lobe

Lobar pneumonia of Lobar pneumonia of the lower lobethe lower lobe

1 .Stage of congestion

2 .Stage of red hepatization

3 .Stage of gray hepatization

4 .Stage of resolution

3. Microscopic Picture 3. Microscopic Picture a. Alveolar capillaries:Congested.b. Alveolar walls: thickened.c. Alveolar spaces:Show bacteria & fluid exudate.

a. Alveolar capillaries:Congested.b. Alveolar walls: thickened.c. Alveolar spaces:

Show bacteria, fibrin, RBCs and

polymorphs.

a. Alveolar capillaries:Less congestedb. Alveolar walls: thin.c. Alveolar spaces:Show dead bacteria, shrinked fibrin, hemolysed RBCs, excess polymorphs and macrophages.

Lobar pneumonia; red hepatization

Lobar pneumonia; grey hepatization

1 .Stage of congestion

2 .Stage of red hepatization

3 .Stage of gray hepatization

4 .Stage of resolution

4. Clinical course - Fever, cough, dyspnea and chest pain.

- At about 9th day the disease ends by crisis (sudden improvement), however

death may occur due to severe toxaemia.

1 .Stage of congestion

2 .Stage of red hepatization

3 .Stage of gray hepatization

4 .Stage of resolution

5. Complications

1. Spread of infection: direct, lymphatic and blood (toxaemia, septicaemia).

2. Lung fibrosis due to failure of resolution.3. Post-pneumonic lung abscess.

BRONCHOPNEUMONIA BRONCHOPNEUMONIA

* Def: Acute suppurative inflammation of bronchioles and

adjacent alveoli characterized by patchy lung consolidation.

* Etilogy:

– Age: extremes of age (young & elderly).

– Predisposing factors: low resistance and bronchitis.

– Causative bacteria: staphylococci, streptococci & H.

influenza.

– Route of infection: endogenous invaders and exogenous

invaders (droplet infection).

* Gross picture: Bilateral.Basal.Multiple consolidated yellowish patches

exuding pus on pressure. Several patches may coalesce to produce confluent bronchopneuomonia.

Enlarged hilar L. nodes.

BronchopneumoniaBronchopneumonia

BronchopneumoniaBronchopneumonia

* Microscopic Picture:I. The broncioles show:

Their lumen shows: necrotic epithelial cells, polymorphs & pus cells.

Their lining: ulceration. Their walls: congested capillaries, neutrophils and

pus cells & exudate.II. The adjacent alveoli show: 3 successive zones: zone

of alveolitis then zone of alveolar collapse and a zone of alveolar dilatation (compensatory emphysema).

* Complications:1. Spread of infection: direct, lymphatic and

blood (toxaemia, septicaemia).2. Lung fibrosis due to failure of resolution.3. Post-pneumonic lung abscess.4. Bronchiectasis.

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