Resp Session 8 Flashcards
What is the pathogenesis of interstitial lung disease (diffuse parenchymal lung disease)?
Start in intersticium –> surrounding structures involved –> acini, alveoli lumen, bronchioles lumen, bronchioles involved –> hypoxia and hypercapnia
How are ventilation, diffusion and perfusion affected in interstitial lung disease?
Ventilation decreased due to decreased compliance
Diffusion decreased due to barrier to gas exchange
Perfusion decreased due to damage/destruction of alveolar capillaries
What pattern on lung function tests is seen in interstitial lung disease?
Restrictive
What cells are involved in interstitial lung disease?
Epithelial Endothelial Mesenchymal Macrophages Recruited inflammatory cells
What is seen on CXR in interstitial lung disease?
Loss of silhouette sign
Increased reticular and nodular shadowing
What is seen on CT scan in interstitial lung disease?
Fibrosis visible as patchy white/grey areas
What is the classic Hx in interstitial lung disease?
Insidious onset with gradual decline SoB
What are the S/S of interstitial lung disease?
Progressive SoB on exertion +/- non-productive cough Clubbing Peripheral/central cyanosis Tachycardia Tachypnoea Decreased chest movement Course crackles Signs of cor pulmonale
What are the 5 types of interstitial lung disease?
Occupational Tx related CT disease Immunological Idiopathic
What can cause CT disease leading to interstitial lung disease?
Rheumatoid arthritis SLE Polymyositis Schleroderma Sjorgen's
At what age do immunological interstitial lung disease pts typically present?
20 or 60-70 y.o.
At what age does idiopathic pulmonary fibrosis typically present?
60-80 y.o.
What is the problem with new therapies for idiopathic pulmonary fibrosis?
Slow mortality and decline in FVC but have significant drug toxicity
What effects can asbestos exposure have in the lungs?
Asbestos plaques Diffuse pleural thickening Benign asbestos pleural effusions Mesothelioma Bronchogenic lung cancer Rounded atelectasis
What is asbestosis?
Interstitial lung disease and asbestos exposure
How is sarcoidosis usually identified?
Incidentally as vast majority indolent
What is found on biopsy in sarcoidosis?
Non-caseating granulomas
What are differentials for sarcoidosis following biopsy?
Lymphoma
TB
What are the Tx options for sarcoidosis?
None
Steroids
Methotrexate (2nd line for steroid sparing)
How is pleural fluid in the reabsorbed in the pleural cavity?
Via stomata on parietal pleural surface –> lymphatic drainage
What can cause increased production of pleural fluid?
Increase in lung interstitial fluid Hydrostatic pressure increases Permeability increases Oncotic pressure decreases Peritoneal fluid seeps through diaphragm Thoracic duct disruption so no drainage
What can cause decreased absorption of pleural fluid?
Lymphatic blockage
Increased systemic venous pressures
What does Light’s criteria state?
Pleural fluid is exudate if:
Pleural fluid protein/serum protein > 0.5
Pleural fluid or serum LDH > 0.6
Pleural fluid LDH > 2/3 upper normal lab limits
What are causes of transudate pleural effusion?
Heart failure Cirrhosis Hypoalbuminaemia Atelectasis Nephrotic syndrome Constrictive pericarditis Meigs syndrome
What are causes of exudate pleural effusion?
Infection Malignancy Rheumatoid arthritis PE Asbestos related Pancreatitis
What can cause haemothorax?
Trauma
Iatrogenic e.g. central line
What can cause chylothorax?
Lymphatic interruption
Lymphoma
Iatrogenic
How does chylothorax appear?
Milky
What indicates empyema?
Decreased pH, decreased glucose and infection
CT and US show septations
What are risk factors for empyema?
Alcoholism
Immunocompromise
What is the Tx of empyema?
Abx +/- drainage
What is the intersticium?
Potential space between alveolar membrane and capillary across which gas can move
What pts develop primary pneumothorax?
Otherwise healthy people, tend to be taller males
Which pts can develop secondary pneumothroax?
Those with underlying lung disease e.g. Cancer or COPD
What are the S/S of pneumothorax?
Pleuritic chest pain
Dyspnoea if large
What is iatrogenic pneumothorax?
Caused by procedures e.g. Central lines
How are small and large pneumothoracies differentiated on CXR?
Small 2cm
What are the treatment options for pneumothorax?
Small, closed w/o significant SoB: observation, discharge and early review
If admittance for obs needed: high flow O2
Pts with SoB: simple aspiration
Recurrent cases: open thoracotomy and pleurectomy
What treatment option is available for pneumothorax pts who do not want surgery?
Chemical pleurodesis via surgical talk into drain to cause irritation of visceral and parietal pleura –> inflammation –> adhesion
How should a tension pneumothorax be diagnosed?
Clinically
What are S/S of tension pneumothorax?
Tachycardia
Hypotension
Decreased chest expansion with hyper resonance and absent breath sounds on one side
Mediastinal shift –> tracheal displacement and shift of apex beat
Hypoxaemia
What is the Tx for tension pneumothorax?
Immediate cannula into affected side
Oxygen
Intercostal chest drain
Resp/thoracic surgical referral to prevent repeat
What congenital chest wall diseases can lead to hypoxia and hypercapnia?
Pectus deformities
Scoliosis
Kyphosis
Muscular dystrophy
What acquired chest wall diseases can lead to hypoxia and hypercapnia?
Trauma
Iatrogenic
Ankylosing spondylitis
Motor neurone disease
What is a radiograph?
Electromagnetic wave of high energy and short wavelength passed through body –> different tissues absorb different amounts –> levels of contrast on grey scale
Why is CXR appropriate for almost all pts?
Low dose of radiation
What two different projections can be used for CXR?
PA projection (conventional, back to front) AP projection
When are AP CXR used?
For pts who are too unwell to stand
What are the potential problems with using AP CXR?
Heart magnified
Lungs under inflated due to sitting position
Scapula over lung fields
What is checked for when assessing inclusion on a CXR?
1st rib
Lateral margin of ribs
Costophrenic angle
How is rotation assessed on CXR?
Spinous processes should be directly in the middle of medial ends of clavicles
Taken during inspiratory phase
At point of intersection of diaphragm and MCL should see 5-7 anterior ribs
How is lung volume assessed on CXR?
What on CXR indicates incomplete inspiration?
Big heart –> increased lung markings
What indicates exaggerated expansion caused by obstructive airway disease on CXR?
Flattened diaphragm
What effects lung volume filling on CXR?
Pt and radiographer factors e.g. explanation, inspiratory effort
How is penetration assessed on CXR?
Vertebrae should be just visible through heart and complete left hemidiaphragm should be visible
What can manipulate penetration on CXR if it is inadequate?
Digital manipulation
What is an artefact on CXR?
External/iatrogenic material that obstructs view e.g. Clothes, buttons, hair, surgical or vascular lines, pacemaker
Give 10 areas of thoracic anatomy which should be examined when assessing a CXR.
Trachea Hila - L should be higher than R Lungs Diaphragm Heart Aortic knuckle Ribs Scapulae Breasts Bowel gas
When might the nipples not show equally on CXR?
Penetration is not equal
Give a systematic approach to assessing a CXR.
Pt demographics Projection Adequacy: RIP Airway Breathing Circulation Diaphragm and dem bones
List review areas in CXR where pathology is commonly missed.
Apices Thoracic inlet Paratracheal stripe AP window Hila Behind heart Below diaphragm Bones Edge of films
What is the silhouette sign?
Adjacent structures of differing density give crisp silhouette and loss of this contour indicates pathology esp. consolidation
What causes mediastinal shift on CXR?
Push= increase in volume or pressure e.g. pleural effusion or tension pneumothroax Pull= decreased volume or pressure e.g. lung collapse
What signs of pneumothorax are visible on CXR?
Visible pleural edge with no visible lung markings
What is visible on CXR in pleural effusion?
Uniform white area visible
Loss of costophrenic angle
Hemidiaphragm obscured
Meniscus of fluid at upper border
What can cause lobar lung collapse?
Aspirated foreign material Mucus plugging Iatrogenic Bronchogenic carcinoma Compression by adjacent mass
How does lobar lung collapse appear on CXR?
Raised epsilateral hemidiaphragm Crowding of ipsilateral ribs Shift of mediastinum due to atelectasis Crowding of pulmonary vessels Luftsichel sign in left upper lobe
How does consolidation appear on CXR?
Dense opacification +/- air bronchogram
What can cause consolidation in lung cancer?
Cells
What differentiates a nodule from a mass when assessing a SoL on CXR?
Nodule 3cm
What causes SoLs?
Malignancy - primary will be single SoL, metastases often have multiple
Benign mass lesion
Inflammation
Congenital
What can a SoL mimic on CXR?
Bone lesion
Cutaneous lesion
Nipple shadow
What additional sign may be visible on CXR in SoL if phrenic diaphragm is implicated?
Raised hemidiaphragm
What should the cardiac index be on PA image?
What is indicated if the heart is the wrong way round on CXR with the apex on R?
Dextrocardia
What is indicated if heart is the wrong way round and liver and gastric bubble are on the opposite side to normal?
Situs inversus
What are CT scans which give much more information than CXR not suitable for all pts?
Deliver much higher doses of radiation, esp if a contrast is used
Why might CT not be appropriate for lactating women?
Sensitivity of breasts to radiation
