S8: lung radiology & LRTIs/pneumonia

Question 1

What is the first thing you should do when looking at a chest x-ray?

Answer 1

Ensure the image if of the correct patient – always look for patient’s name and the date
If previous images are available, always compare the new with the old

Question 2

Describe the basic radiological principles used to evaluate the quality of a chest x-ray

Answer 2

RIPE
Rotation – medial aspect of each clavicle should be equidistant from spinous processes & spinous processes should also be vertically orientated against the vertebral bodies
Inspiration – 5-6 anterior ribs, lung apices, both costophrenic angles & lateral rib edges should be visible
Projection – AP vs PA
Exposure – left hemidiaphragm should be visible to the spine and vertebrae visible behind the heart

Question 3

What does ABCDE stand for?

Answer 3

Airway
Breathing 
Cardiac
Diaphragm
Everything else

Question 4

Describe what to look for ‘A’ in chest x-rays

Answer 4

Trachea – inspect for deviation
Carina and bronchi – division should be clearly visible
Hilar structures – usually the same size

Question 5

Describe what to look for ‘B’ in chest x-rays

Answer 5

Lungs – divide each lung into three zones and look for abnormalities
Pleura – not usually visible

Question 6

Describe what to look for ‘C’ in chest x-rays

Answer 6

Assess heart size

Assess the heart’s borders

Question 7

Describe what to look for ‘D’ in chest x-rays

Answer 7

Diaphragm
Should be indistinguishable from underlying liver
Free gas under diaphragm -> urgent review
Costophrenic angles – should be clearly visible

Question 8

Describe what to look for ‘E’ in chest x-rays

Answer 8

Mediastinal contours – aortic knuckle, aortopulmonary window
Bones
Soft tissues
Tubes
Lines 
Artificial heart valves 
Pacemaker

Question 9

Outline the distribution and composition of the normal flora of the respiratory tract

Answer 9

Common – viridans streptococci, Neisseria spp., anaerobe candida sp
Less common – strep pneumoniae, strep pyogenes & haemophilus influenzae
Lungs are not sterile – alveolar microbiota, aspiration, blood stream spread & direct spread

Question 10

Outline the natural defences of the respiratory tract

Answer 10

Mucociliary clearance mechanisms – nasal hairs, ciliated columnar epithelium of the respiratory tract
Cough & sneezing reflex
Respiratory mucosal immune system – lymphoid follicles of the pharynx and tonsils, alveolar macrophages, secretory IgA and IgG
Alveolar microbiota

Question 11

List the main lower respiratory tract diseases

Answer 11

Acute bronchitis 
Bronchiectasis 
Bronchiolitis 
Empyema – collection of pus in the pleural cavity 
Lung abscess 
Pneumonia

Question 12

Define pneumonia

Answer 12

General term denoting inflammation of the lung parenchyma due to infection
Common feature – cellular exudate in the alveolar spaces

Question 13

What is the difference between lobar pneumonia and bronchopneumonia?

Answer 13

Lobar pneumonia = pneumonia is localised to a particular lobe/s of the lungs
Bronchopneumonia = pneumonia is more diffuse and patchier

Question 14

Describe community acquired pneumonia

Answer 14

Typically present with symptoms and signs consistent with a lower respiratory tract infection – cough, dyspnoea, chest pain, fever
Commonest causative organism: streptococcus pneumoniae
Other organisms include: haemophilus influenzae, Moraxella catarrhalis, group A strep & staph aureus

Question 15

Describe atypical organisms which cause atypical pneumonia

Answer 15

Mycoplasma pneumonia – lacks a peptidoglycan bacterial cell wall
Chlamydia pneumonia – obligate intracellular pathogen
Legionella pneumophila – intracellular pathogen

Question 16

Describe hospital acquired pneumonia

Answer 16

Infection of the lower respiratory tract in hospitalised patients, occurring < 48 hours after admission and was not incubating at the time of admission
Gram negative bacteria usually cause this – pseudomonas aeruginosa, E. coli, klebsiella pneumoniae etc

Question 17

Describe the clinical features of pneumonia

Answer 17

Malaise
Fever
Cough productive of sputum
Persistent dry cough that does not resolve with time should prompt consideration of atypical pneumonia
New focal chest signs: crackles, decreased breath sounds, dullness to percussion, wheeze & increased vocal resonance over area of consolidation

Question 18

Describe how to assess severity of pneumonia in hospital setting

Answer 18

CURB-65 score 
C – new mental confusion
U – urea > 7mmol/L
R – respiratory rate > 30 per min
B – blood pressure (systolic BP < 90/DBP < 60 mmHg) 
Age > 65 years 
Score 2 = ?admit
Score 2-5 = manage as severe 
CRB is used in the community

Question 19

Describe the management of pneumonia

Answer 19

Maintain good oral fluid intake
Anti-pyretic drugs to reduce fever and malaise
More severe – IV fluids & oxygen

Question 20

Outline the antibiotics given for CAP

Answer 20

Mild/moderate: amoxicillin, or doxycycline or erythromycin/clarithromycin
Moderate/severe: co-amoxiclav AND clarithromycin/doxycycline

Question 21

List complications of pneumonia

Answer 21

Initial infection progression – empyema/lung abscess/bacteraemia
-non-resolving CAP: closed space infections, bronchial obstruction, chronic CAP, incorrect initial diagnosis

Question 22

Outline the antibiotics given for HAP

Answer 22

First-line: co-amoxiclav

Second-line/ITU: piperacillin/tazobactam or meropenem

Question 23

Describe aspiration pneumonia

Answer 23

Aspiration of food, drink, saliva or vomit can lead to pneumonia
More likely in individuals whose level of consciousness is altered – epilepsy, alcoholics & drowning

Question 24

Describe preventative measures for pneumonia

Answer 24

Immunisation – flu vaccination, pneumococcal vaccine
Chemoprophylaxis
Smoking advice