Pathology

Question 1

What is the congestion phase of lobar pneumonia

Answer 1

Alveoli filled with oedema fluid and bacteria

Question 2

What is the red hepatisation phase of lobar pneumonia

Answer 2

Firm, ‘meaty’ and airless appearance of lung
Alveolar capillary dilatation
Strands of fibrin extending from one alveolus to another via inter-alveolar pores of Kohn
Neutrophils in alveoli
Pleura: Fibrinous exudate

Question 3

What is the gray hepatisation phase of lobar pneumonia

Answer 3

Less hyperaemia

Macrophages, neutrophils + fibrin

Question 4

What is the resolution phase of lobar pneumonia

Answer 4

Lysis and removal of fibrin via sputum +
lymphatics.
Begins after 8-9 days (without antibiotics).

Question 5

what can lead to bronchopneumonia

Answer 5

Infants, young children and the elderly.
Usually secondary to other conditions associated with local and general defence mechanisms
viral infections (influenza, measles)
aspiration of food or vomitus
obstruction of a bronchus (foreign body or neoplasm)
inhalation of irritant gases
major surgery
chronic debilitating diseases, malnutrition

Question 6

What is atypical pneumonia

What is the most commonest cause

Answer 6

Inflammatory changes largely in the alveolar walls (interstitial)

SARS (coronavirus)

Question 7

microbiological investigations

Answer 7

routine sputum culture and sensitivity
blood cultures
urine for pneumococcal antigen
investigations for legionella if suspected:
sputum for culture and immunofluorescence
urine for legionella antigen
PCR/immunofluorescence for atypical organisms and viruses
pleural fluid if available for microscopy, culture and antigen detection

Question 8

What is the organism most likely in a patient with pneumonia and extra-pulmonary manifestations e.g. on hands or feet

Answer 8

Mycoplasma

Question 9

What organisms would be most likely if the patient has developed the pneumonia during hospital admission for other reasons?

Answer 9

E.coli, Klebsiella spp., proteus spp., S. pneumoniae, S. aureus

Question 10

Complications of lobar pneumonia

Answer 10

1. Abscess formation
2. Empyema
3. Failure of resolution ⇒ intra-alveolar scarring
   (‘carnification’) ⇒ permanent loss of ventilatory
   function of affected parts of lung.
4. Bacteraemia:
   Infective endocarditis
   Cerebral abscess / meningitis
   Septic arthritis
5. Amyloidosis