Session 10 Flashcards
CXR Evaluation
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
Review areas on a chest x-ray
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
Silhouette sign
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
Mediastinal shift
Adequately centered image
Look at Trachea Cardiac shadow
Pushed or pulled Push = increase volume or pressure Pull = decrease volume or pressure
Descriptive terms used for x rays
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
Specific CXR findings
Pneumothorax Pleural effusion Consolidation Space occupying lesions within a lung Lobar collapse Estimate the cardiac index
Pneumothorax
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
Pleural effusion/fluid
Collection of fluid in the pleural space Uniform white area Loss of costophrenic angle Hemidiaphragm obscured Meniscus at upper border Beware the supine CXR
Lobar lung collapse
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
Consolidation
Filling of small airways/alveoli with STUFF! Pus - pneumonia Blood - haemorrhage Fluid - oedema Cells - cancer
Dense opacification
Volume preserved +/- increased
Air bronchogram
Space occupying lesion -
Nodule < 3cm
Mass > 3cm
Single vs Multiple
Causes Malignant Primary Metastases Benign mass lesion Inflammatory Congenital Mimics Bone lesion Cutaneous lesion Nipple shadow
Cardiac index
Ratio Normal <50% Must be an PA image
BEWARE OVERESTIMTAION ON AP IMAGE
slide 56
Computed Tomography (CT)
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
Other imaging modalities
Ultrasound
MRI
Nuclear Medicine
Where does the air come from in a pneumothorax?
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
Primary, spontaneous pneumothorax
• 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
Secondary pneumothorax
- 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
Symptoms and signs (Simple pneumothorax)
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
Chest x-ray of pneumothorax example
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
Treatment of simple pneumothorax
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
Tension pneumothorax
• 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.
Tension pneumothorax severity?
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
Symptoms and Signs of a Tension Pneumothorax
• 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
Tension pneumothorax x-ray
inser slide 17
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
Treatment of a tension pneumothorax
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
Compare treatment of tension pneumothorax with simple pneumothorax
slide 20 lec 2
Define: Pleural effusion
- haemothorax
- Cylothorax
- Empyema
- 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
Production and absorption of pleural fluid
• 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
Pleural effusion - Transudate
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
Pleural effusion - exudate
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
Transudate versus exudate
Fluid is an exudate if one of the following Light’s criteria is present:
slide 27
Symptoms and signs of pleural effusion
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
Radiology of pleural effusion
- 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)
CT scan of pleural effusion
Useful to detect underlying pathology and confirm effusion
Unilateral vs Bilateral Pleural effusion
Note: Bilateral blunting of costo-phrenic angles will be seen on cxr
panopto
Diagnosis of cause of pleural effusions
• 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
Treatment of pleural effusion
• 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
