Session 10

Question 1

CXR Evaluation

Answer 1

 Systematic ABC approach  Patient demographics  Projection  Adequacy  Adequacy/Airway- Trachea
 Bronchi  Hila  Breathing - Lungs
 Pleural spaces
 Lung interfaces Circulation -  Mediastinum  Aortic arch  Pulmonary vessels  Hila  Right heart border  Right atrium  Middle lobe interface  Left heart border  Left ventricle  Lingula interface  Diaphragm / Dem bones - Free gas
 Nodules
 Fracture/dislocation
 Mass  Review areas

Question 2

Review areas on a chest x-ray

Answer 2

 Areas we (all of us!) commonly miss pathology
 Apices = Pneumothorax  Thoracic inlet = Mass  Paratracheal stripe = Mass/lymph nodes  AP window = Lymph nodes  Hila = Mass/collapse  Behind heart = Mass  Below diaphragm = Pneumoperitoneum/mass  Bones – all of them! = Fracture/mass/missing  Edge of films

Question 3

Silhouette sign

Answer 3

 Adjacent structures of differing density form a crisp SILHOUETTE
Heart next to lung = white next to black
 Loss of this contour can locate pathology
Loss of SILHOUETTE sign!

Silhouette sign 2
 Right heart border = RML  Left heart border = lingula  Paratracheal stripe = mediastinal disease  Chest wall = lung/pleura/rib  Aortic knuckle = Ant mediastinum/upper lobe  Diaphragm = lower lobe  Horizontal fissure = Ant segment upper lobe

Question 4

Mediastinal shift

Answer 4

 Adequately centered image
 Look at  Trachea  Cardiac shadow
 Pushed or pulled  Push = increase volume or pressure  Pull = decrease volume or pressure

Question 5

Descriptive terms used for x rays

Answer 5

 Tissue involved - Lung, heart, aorta, bone etc
 Size - Large/Small/Varied
 Side - Right/Left - Unilateral/Bilateral
 Number - Single/Multiple
 Distribution - Focal/Widespread
 Position - Anterior/Posterior/Lung zone etc
 Shape - Round/Crescentic/etc
 Edge - Smooth/Irregular/Spiculated
 Pattern - Nodular/Reticular (net-like)
 Density - Air/Fat/Soft-tissue/Calcium/Metal

Question 6

Specific CXR findings

Answer 6

 Pneumothorax  Pleural effusion  Consolidation  Space occupying lesions within a lung  Lobar collapse  Estimate the cardiac index

Question 7

Pneumothorax

Answer 7

 Air trapped in the pleural space.
 Spontaneous (primary), or as a result of underlying lung disease (secondary).
 The most common cause is trauma, with laceration of the visceral pleura by a fractured rib.
 Lung edge measures more than 2 cm from the inner chest wall at the level of the hilum, it is said to be ‘large.’
 Tracheal or mediastinal shift away from the pneumothorax and depressed hemirdiaphragm, the pneumothorax is said to be under ‘tension.
 Signs  Visible pleural edge  Lung markings not visible beyond this edge

Question 8

Pleural effusion/fluid

Answer 8

 Collection of fluid in the pleural space
 Uniform white area
 Loss of costophrenic angle
 Hemidiaphragm obscured
 Meniscus at upper border
Beware the supine CXR

Question 9

Lobar lung collapse

Answer 9

 Volume loss within lung lobe
 Causes  Luminal  Aspirated foreign material  Mucous plugging  Iatrogenic  Mural  Brochogenic carcinoma  Extrinsic  Compression by adjacent mass
 Generic findings  elevation of the ipsilateral hemidiaphragm  crowding of the ipsilateral ribs  shift of the mediastinum towards the side of atelectasis  crowding of pulmonary vessels

Question 10

Consolidation

Answer 10

 Filling of small airways/alveoli with STUFF!  Pus - pneumonia  Blood - haemorrhage  Fluid - oedema  Cells - cancer
 Dense opacification
 Volume preserved +/- increased
 Air bronchogram

Question 11

Space occupying lesion -

Answer 11

 Nodule < 3cm
 Mass > 3cm
 Single vs Multiple
 Causes  Malignant  Primary  Metastases  Benign mass lesion  Inflammatory  Congenital  Mimics  Bone lesion  Cutaneous lesion  Nipple shadow

Question 12

Cardiac index

Answer 12

 Ratio  Normal <50%  Must be an PA image
BEWARE OVERESTIMTAION ON AP IMAGE
slide 56

Question 13

Computed Tomography (CT)

Answer 13

 Dose  CXR = 0.02 mSv  Screening Chest CT (low-dose) = 2 mSv  CT pulmonary angiogram = 15 mSv  Standard Chest = 7 mSv
Local dose for CT chest and CTPA ~ 2-4 mSV

Question 14

Other imaging modalities

Answer 14

Ultrasound
MRI
Nuclear Medicine

Question 15

Where does the air come from in a pneumothorax?

Answer 15

The lung (commonest by far) • Primary spontaneous pneumothorax • Secondary to underlying lung disease or trauma • Iatrogenic – high pressure ventilation, central line placement
Through the chest wall (rare) • Trauma
Both the lung and through the chest wall (rare) • Trauma. e.g. penetrating chest injuries

Question 16

Primary, spontaneous pneumothorax

Answer 16

• Most commonly in young, tall, thin males • no lung disease or thoracic trauma • Smoking increases risk X 9
Most cases probably have a small sub-pleural bleb or bulla (an air filled sac) that bursts, allowing air into the pleural cavity

Question 17

Secondary pneumothorax

Answer 17

• Secondary to underlying lung disease: • COPD, Asthma • Bronchiectasis including cystic fibrosis • Lung cancer • Pulmonary infections including pneumonia and TB
• Secondary to trauma • A fractured rib  puncture the visceral pleura • Severe blunt chest trauma • Penetrating chest injuries
• Iatrogenic (due to a diagnostic or therapeutic procedure) • to high pressure ventilation • Insertion of central lines / pacing

Question 18

Symptoms and signs (Simple pneumothorax)

Answer 18

History • Sudden onset • Pleuritic chest pain and breathlessness ± history of lung disease / trauma (if secondary)
Examination: • Chest movement: Reduced on affected side • Percussion note: Hyper- resonant or resonant on affected side • Breath sounds: (Vesicular) reduced /absent on affected side Vocal Resonance: Reduced

Question 19

Chest x-ray of pneumothorax example

Answer 19

Right sided pneumothorax
• Right side is hyperlucent – darker than normal side (air in pleural space vs lung tissue)
• Absent lung markings on right side (beyond edge of collapsed lung)
• Edge of collapsed lung is seen (yellow arrows)
insert mage for both question and answer of slide 9 lec 2

Question 20

Treatment of simple pneumothorax

Answer 20

If patient is symptomatic  and has a small pneumothorax : needle aspiration may be sufficient  and has a large pneumothorax: insertion of chest drainage.
• Chest drain placement
• In the safe triangle
• 5th Intercostal space • In the mid-axillary line
• Just above 6th rib, to avoid neurovascular bundle
insert slide 11 and 12 lec 2

Question 21

Tension pneumothorax

Answer 21

• Tension pneumothorax can occur due to any aetiology
• Defined as any size of pneumothorax causing mediastinal shift and cardiovascular collapse
Occurs whenever air can enter the pleural cavity on inspiration (either from the chest wall or the visceral pleura)
But cannot escape on expiration because of a flap that closes on expiration. This acts like a one-way valve.

Question 22

Tension pneumothorax severity?

Answer 22

Tension pneumothorax is life threatening
• Mediastinal shift – compresses normal lung
• Increased intrapleural pressure is higher than atmospheric pressure for much of the respiratory cycle.
• As a result, venous return is impaired  cardiac output drops
• results in hypoxaemia and haemodynamic compromise

Question 23

Symptoms and Signs of a Tension Pneumothorax

Answer 23

• Severe distress and dyspnoea • Pleuritic chest pain • Fatigue
• Tachycardia and hypotension • Raised JVP • Deviated trachea • Displaced apex beat • Hyper-resonant percussion note • Absent breath sounds
Diagnosis is clinical …….Can’t wait for CXR confirmation Needs emergency needle decompression of chest

Question 24

Tension pneumothorax x-ray

inser slide 17

Answer 24

Trachea:  Deviated to Left
Heart :  Displaced to the left
Right lung – Hyperlucent, with absent lung markings
Edge of collapsed lung visible
insert slide 17 lec 2

Question 25

Treatment of a tension pneumothorax

Answer 25

Emergency needle decompression of the chest:
Insert a plastic cannula (Venflon) into the second intercostal space in the mid-clavicular line
Cannula left in place till chest drain inserted (in the 4th ICS mid axillary line) when patient is stable

Question 26

Compare treatment of tension pneumothorax with simple pneumothorax

Answer 26

slide 20 lec 2

Question 27

Define: Pleural effusion

• haemothorax
• Cylothorax
• Empyema

Answer 27

• Is an excess of fluid in the pleural cavity, • Imbalance in the normal rate of pleural fluid production and absorption
• Effusion: Pleural fluid is a transudate or exudate from blood
• Haemothorax: When the fluid is blood (e.g. trauma) • Chylothorax: When the fluid is lymph (e.g. leak from lymphatic duct ..trauma) • Empyema: When the fluid is pus

Question 28

Production and absorption of pleural fluid

Answer 28

• Normally 2400 ml of pleural fluid is produced each day by the parietal pleura
• This is normally absorbed by the lymphatics.
• A pleural effusion occurs when there is dysfunction of either production or absorption
Pleural fluid formation Depends on ‘Starling’ Forces in systemic capillaries in parietal pleura
Key factors: hydrostatic pressure and colloid osmotic pressure

Question 29

Pleural effusion - Transudate

Answer 29

Increased formation of pleural fluid
• Commonest cause is congestive heart failure (increased pressure in venous end of capillary)
• Hypoproteinaemia ( reduced colloid oncotic pressure) • Nephrotic syndrome (increased protein loss in the urine) • Liver failure (reduced protein synthesis in the liver cirrhosis)
• less common causes
The large protein molecules do not pass through the pores in the capillary  hence it is a transudate

Question 30

Pleural effusion - exudate

Answer 30

Increased capillary permeability due to inflammation and results in an exudate
• Infection – Pneumonia, TB
• Cancer (primary or secondary)
• Cancer may also block lymphatic drainage
• Pulmonary infarction due to pulmonary embolism
• Other causes
Protein molecules pass through the ‘leaky’ capillary  resulting in an exudate

Question 31

Transudate versus exudate

Answer 31

Fluid is an exudate if one of the following Light’s criteria is present:
slide 27

Question 32

Symptoms and signs of pleural effusion

Answer 32

History • Breathlessness (more gradual onset – days) • Chest pain (pleuritic) • ± features of causative disease (e.g. congestive cardiac failure, or lung malignancy)
Examination: • Chest movement: Reduced on affected side • Percussion note: “Stony” Dull on affected side • Breath sounds: (Vesicular) reduced /absent on affected side Vocal Resonance: Reduced

Question 33

Radiology of pleural effusion

Answer 33

• Fluid always collects in the most dependant part – opacity is in lower zone (in upright position)
• Cannot see outline of diaphragm
• Dense, Homogeneous opacity • Upper border curved (meniscus)

Question 34

CT scan of pleural effusion

Answer 34

Useful to detect underlying pathology and confirm effusion

Question 35

Unilateral vs Bilateral Pleural effusion

Answer 35

Note: Bilateral blunting of costo-phrenic angles will be seen on cxr
panopto

Question 36

Diagnosis of cause of pleural effusions

Answer 36

• History • Examination • Radiology • Diagnostic aspiration – best done under ultrasound guidance. Send aspirate for: • Protein content, Lactate Dehydrogenase levels, • Bacterial examination (including Gram stain) and culture • Cytology

Question 37

Treatment of pleural effusion

Answer 37

• Depends on the underlying condition and extent of the pleural effusion • Treat the underlying condition • In very symptomatic patients, chest aspiration might be indicated
• Recurrent effusions (particularly malignant) may require • indwelling pleural catheter for intermittent drainage
OR • Pleurodesis: Obliteration of the pleural space Usually by introducing Talc into pleural space after draining effusion. Causes the visceral and parietal pleura to become adherent  obliterates pleural space