Pathology of respiratory tract infections (not done bc the lecture is shite)

Question 1

What determines the ability of a microorganism to infect a host?

Answer 1

Pathogenicity

Capacity of the host to resist infection

Population at risk

Question 2

What are the main infections of the Upper respiratory tract?

Answer 2

Coryza - common cold

Sore throat syndrome

Acute Laryngotracheobronchitis (Croup)

Laryngitis

Sinusitis

Acute Epiglottitis

Question 3

What is acute epiglottitis?

Answer 3

Acute infection and inflammation of the epiglottis

Question 4

What causes acute epiglottitis?

Answer 4

Haemophilus influenzae (type b - Hib)

Group A beta-haemolytic Streptococci

Rarely caused by Parainfluenza virus type 4 but other viruses may also be responsible

Question 5

What are the main lower respiratory tract infections?

Answer 5

Bronchitis

Bronchiolitis

Pneumonia

Question 6

What are defences against pathogens used by the respiratory tract?

Answer 6

Macrophage-mucociliary escalator system

General immune system

Respiratory tract secretions

Upper respiratory tract as a ‘filter’

Question 7

Why is the macrophage-mucocilliary escalator system so important?

Answer 7

The lower respiratory tract is normally sterile and should be kept that way

Question 8

What are the possible clearance pathways for a pathogen using the macrophage-mucocilliary escalator system?

Answer 8

Pathogen trapped in mucous and out of respiratory system into mouth

or

Pathogen cleared by alveolar macrophages via phagocytosis then carried to lymph nodes

Question 9

What is the effect of influenza on the lower respiratory tract?

Answer 9

Destruction of bronchial epithelium

This means the escalator system doesnt work as there are no cillia

Question 10

Pneumonia can be classified aetiologically, anatomically and microbiologically

What are the aetiological classes of pneumonia?

Answer 10

Community Acquired Pneumonia

Hospital Acquired (Nosocomial) Pneumonia

Pneumonia in the Immunocompromised

Atypical Pneumonia

Aspiration Pneumonia

Recurrent Pneumonia

Question 11

What are the different anatomical types of pneumonia?

Answer 11

Lobar

Broncho

Segmental

Question 12

How does bronchopneumonia differ from lobar pneumonia on a CXR?

Answer 12

Bronchopneumonia has patchy, often bilateral opacification. They are closer to the hilla.

Lobar pneumonia has larger, widespread areas of opacification

Question 13

What other conditions can be secondary to pneumonia?

Answer 13

Pleurisy

Pleural effusion

Empyema

Organisation:
Constrictive bronchiolitis, COP, mass lesion

Lung abscess

Bronchiectasis