Pathology of pulmonary infection

Question 1

What is Acute Epiglottitis?

Answer 1

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 2

Describe the mucociliary escalator system

Answer 2

Main mechanism to keep lungs sterile and involves general immune system, respiratory tract secretions and the upper respiratory tract acting as a ‘filter’

Any failure in any these systems increases the risk of respiratory tract infection

Question 3

What makes up the mucociliary escalator system?

Answer 3

Alveolar macrophages

mucociliary escalator and cough reflex

Question 4

Describe bronchopneumonia

Answer 4

Bacterial infection and affects bronchioles and alveolate tissue around those bronchioles

Cellular pathology – acute inflammation when bacterial infection

Doctor never involved in diagnosis of acute inflammation
Can be observed in sputum sample

Often 
bilateral basal 
patchy opacification, 
relating to 
the focal nature of 
the consolidation

Question 5

Describe lobar pneumonia

Answer 5

Caught outside in community

Acute inflammatory process – organisms that cause this cause vigorous response and fill the entire lobe until it reaches pleural limits

Question 6

Describe organisation of pneumonia

Answer 6

mass lesion
COP(cryptogenic organising pneumonia (BOOP))
Constrictive bronchiolitis

Question 7

Describe lung abscess

Answer 7

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

Question 8

What is the pathological dilation and clinical symptoms of bronchiectasis?

Answer 8

Severe Infective Episode
Recurrent Infections - many causes
Proximal Bronchial Obstruction
Lung Parenchymal Destruction

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

Question 9

Describe the factors related to aspiration pneumonia

Answer 9

Vomiting

Oesophageal Lesion
Obstetric Anaesthesia
Neuromuscular Disorders
Sedation

Question 10

What type of transport occurs after terminal bronchiole?

Answer 10

Diffusion

Question 11

What is Hb affinity for oxygen?

Answer 11

blood leaving capillary bed is 98% saturated for FIO2 of only 0.21 (21%)

Question 12

Name the values of normal PaO2 and PaCO2

Answer 12

Normal PaO2 10.5 – 13.5 kPa

Normal PaCO2 4.8 – 6.0 kPa

Question 13

What are the values of PaO2 for type 1 respiratory failure?

Answer 13

PaO2 <8 kPa (PaCO2 normal or low)

Question 14

What are the values of PaCO2 for type 2 respiratory failure?

Answer 14

PaCO2 >6.5 kPa (PaO2 usually low)

Question 15

Describe the four abnormal states associated with hypoxaemia

Answer 15

Ventilation / Perfusion imbalance - V/Q
Diffusion impairment
Alveolar Hypoventilation
Shunt

Question 16

What is the protective mechanism in hypoxia?

Answer 16

Do not send blood to alveoli short of oxygen!

Question 17

What is Physiological pulmonary arteriolar vasoconstriction?

Answer 17

When alveolar oxygen tension falls
Can be localised effect
All vessels constrict if there is arterial hypoxaemia

Question 18

Describe some complication of pneumonia

Answer 18

Pleurisy, pleural effusion and empyema, lung abscess and bronchiectasis