Pathology of Respiratory Tract Infections

Question 1

Upper respiratory tract infection

Answer 1

• Coryza - common cold
• Sore throat syndrome
• Acute Laryngotracheobronchitis (Croup)
• Laryngitis
• Sinusitis
• Acute Epiglottitis

Question 2

Lower respiratory tract infections

Answer 2

• Bronchitis
• Bronchiolitis
• Pneumonia
• Consequences
• Possible Complications

Question 3

Respiratory tract defence mechanisms

Answer 3

• Macrophage-mucociliary escalator system
  
  • ALVEOLAR MACROPHAGES
  • MUCOCILIARY ESCALATOR
  • COUGH REFLEX
• General immune system
  
  • Humoral and cellular immunity
• Respiratory tract secretions
• Upper respiratory tract as a ‘filter’

Question 4

Classifications of pneumonia

Answer 4

• Anatomical
  ~ Understand radiology
• Aetiological (Circumstances)
  ~ probably more useful
• Microbiological
  ~ ultimately appropriate for treatment

Question 5

Aetiological classification of pneumonia

Answer 5

• Community Acquired Pneumonia
• Hospital Acquired (Nosocomial) Pneumonia
• Pneumonia in the Immunocompromised
• Atypical Pneumonia
• Aspiration Pneumonia
• Recurrent Pneumonia

Question 6

Patterns of pneumonia

Answer 6

• Bronchopneumonia
• Segmental
• Lobar

Question 7

Anatomical classification of pneumonia

Answer 7

• Hypostatic (in the lower part of lung)
• Aspiration
• Obstructive, Retention, Endogenous Lipid

Question 8

Outcome/complications of pneumonia

Answer 8

• Pleurisy, Pleural Effusion and Empyema
• Organisation
  ~ mass lesion
  ~ COP(cryptogenic organising pneumonia (BOOP))
  ~ Constrictive bronchiolitis
• Lung Abscess
• Bronchiectasis

Question 9

Lung abscess

Answer 9

• Obstructed Bronchus: tumour
• Aspiration
• Particular Organism
  
  • Staph aureus, some pneumococci, Klebsiella
• Metastatic in Pyaemia
• Necrotic Lung (2o infection)

Question 10

Bronchiectasis 1

Answer 10

Pathological dilatation of Bronchi due to:
- Severe Infective Episode
- Recurrent Infections - many causes
- Proximal Bronchial Obstruction
- Lung Parenchymal Destruction

Question 11

Bronchiectasis 2

Answer 11

• 75% start in childhood
• COUGH, ABUNDANT PURULENT FOUL SPUTUM, haemoptysis, signs of chronic infection
• Coarse crackles, clubbing
• Thin section CT
• Postural Drainage, Antibiotics, Surgery

Question 12

Recurrent lung infection - how are the defences failing?

Answer 12

• Local bronchial obstruction: tumour, foreign body
• Local pulmonary damage: bronchiectasis
• Generalised lung disease: cystic fibrosis, COPD
• Non-respiratory disease: immunocompromised

Question 13

Aspiration pneumonia

Answer 13

• Vomiting
• Oesophageal Lesion
• Obstetric Anaesthesia
• Neuromuscular Disorders
• Sedation