Investigations in Respiration

Question 1

What is the first imaging technique which should be used?

Answer 1

Chest X-ray

Question 2

What view should chest x-rays be taken from?

Answer 2

Postero-anterior

Question 3

What are the problems with antero-posterior chest x-rays?

Answer 3

Cardiac outline is too big
Scapulae can’t be moved out of the way
Should only be given if the patient can’t stand or go the radiology department

Question 4

How is lobar collapse indicated in a CXR?

Answer 4

Loss of volume or rib crowding

Question 5

What direction do the lower lobes collapse?

Answer 5

Downwards towards the mediastinum

Question 6

What does the right upper lobe look like when collapsed?

Answer 6

Looks like an arch over the remaining lung

Question 7

What does the right middle lobe look like when collapsed?

Answer 7

Obscures the right heart border

Question 8

What direction does the left upper lobe collapse?

Answer 8

Collapses against the anterior chest wall

Question 9

What indicates a whole lung collapse?

Answer 9

The mediastinum will shift towards the side of the collapse

Question 10

How does pleural effusion present on a CXR?

Answer 10

Blunting of the costophrenic angle if small, if larger a whole hemithorax can be opaque, mediastinum will shift away from the effusion

Question 11

How does fibrosis present on a CXR?

Answer 11

Streaky shadowing, loss of lung volume and mediastinal shift towards area if local
If general, honeycomb appearance, diffuse shadows with multiple circular translucencies a few mm in diameter

Question 12

What are round shadows on a CXR indicative of?

Answer 12

Lung cancer

Question 13

What are the causes of military mottling on CXR (lots of minute opacities)

Answer 13

Tuberculosis
Pneumoconiosis 
Sarcoidosis
Idiopathic pulmonary fibrosis
Pulmonary oedema (although usually perihilar with larger fluffy shadows)
Pulmonary microlithiasis (rare)

Question 14

What is the second investigation if a cancer is suspected?

Answer 14

CT scan

Question 15

When is a PET scan used?

Answer 15

After a tumour has been found to assess whether it is malignant or benign and to establish if there are any metastases which haven’t been detected by the CT scan before certain treatments are carried out

Question 16

What is a ventilation perfusion scan?

Answer 16

Xenon-133 gas is inhaled and it’s distribution is detected at the same time as the perfusion scan, macro-aggregated human albumin is injected intravenously, the particles remain in the pulmonary capillaries for a few hours. A gamma camera detects the particles position and distribution, very useful in detecting pulmonary embolus

Question 17

How does spirometry work?

Answer 17

Patient takes maximum respiration and then forces expiration for as long as possible into the spirometer. The FEV1, FEV and FVC are all found and can be compared to the normal values for healthy individuals

Question 18

What are the spirometry results for obstructive lung disease?

Answer 18

FEV1/FVC will be less that 70% because oxygen movement out of the lungs is inhibited, FVC can be normal but the FEV1 will be low causing a low ratio

Question 19

What are the spirometry results for restrictive lung disease?

Answer 19

FEV1/FVC will be normal because they will have a normal ratio but the FVC will be low – the problem is inflating the lungs not moving the air in the lungs out

Question 20

What is Peak flow rates main purpose?

Answer 20

Diagnosing asthma and monitoring exacerbations of asthma

Question 21

What is Peak expiratory flow rate?

Answer 21

Patient inhales their complete lung volume then exhales forcefully, the best of 3 attempts is recorded.

Question 22

When are microbiological studies into sputum useful?

Answer 22

Pneumonia
Tuberculosis
Unusual clinical problems
Aspergillus