Pathology of the respiratory tract infection

Question 1

What does infection of the RTI depend on?

Answer 1

1-pathogen:
-primary: causes disease when it enters healthy system 
-facultative
-opportunistic 
2-capacity to resist infection
-age of patient
-immune system
3-population at risk

Question 2

common infections

Answer 2

upper:

• sinusitis
• acute epiglottitis
• laryngitis
• coryza
• croup

LOWER:

• bronchitis
• pneumonia

Question 3

Defence mechanism

Answer 3

• immune system: humoral and cellular
• macrophage-mucociliary escalator
• upper respiratory tract as a filter
• secretions

Question 4

How does the macrophage-mucociliary escalator act?

Answer 4

Pathogens can be removed by 2 systems:

• from periphery: into lung and then into lymph system
• from main bronchus: up mucociliary escalator-cough reflex

Question 5

Pneumonia classifications

Answer 5

Aetological:

• hospital acquired
• community acquired
• recurrent
• atypical
• immunocompromised

Pathology:

• Segmental
• Lobar
• Bronchopneumonia: areas of consolidation where pus has been deposited between segments of normal tissue

Question 6

Outcomes of pneumonia

Answer 6

-Resolves
-Pleurisy/pleural effusion/empyema
-organisation:
Cryptogenis organising pneumonia=COP- contraction of the small airways
-lung abcess: tumour/aspiration/organism/necrotic tissue
-bronchoectasis :permanent enlargement of bronchus. Caused by infection or proximal bronchial obstruction

Question 7

symptoms/investigation and treatment of pneumonia

Answer 7

symptoms:
-75% presents in childhood
-sputum-haemoptysis
-course crackling 
investigations:
-thin section CT
Treatment:
-antibiotics
-surgery
-postural drainage

Question 8

symptoms associated with aspiration pneumonia

Answer 8

• vomiting
• neuromuscular disorder
• oesophageal lesion
• obstetric anaestesia