Interstitial Lung Disease Flashcards
What is the ‘interstitial space’?
When should it appear and what might it contain?
A potential space between alveolar cells and the capillary basement membrane.
It is only apparent in disease states and may contain fibrous tissue, cells or fluid
Which structures does interstitial disease affect?
Acini + alveolar lumen, bronchioles + bronchiolar lumen and cell types; epithelial, endothelial, macrophages, inflamm cells, etc.
What does interstitial lung disease lead to?
Temporary or permanent changes in the interstitial tissues interferes with diffusion of gases and changes the mechanics of breathing
Is interstitial lung disease obstructive or restrictive?
Fibrous tissue in the interstitium makes the lungs less compliant - producing a restrictive deficit
What are the 5 types of interstitial lung disease?
- Occupational
- treatment related
- CT disease
- Immunological
- Idiopathic
How long has the patient had interstitial lung disease if they have the acute, sub-acute or chronic version?
Acute: days-weeks
Sub-acute: weeks- months
Chronic: months-years
How does interstitial lung disease present?
- progressive breathlessness
- dry cough
- extra-pulmonary symptoms: fever, joint pain, lethargy, etc.
What are you looking for in a history that might complete your diagnosis?
- Onset of symptoms: duration of symptoms
- Past medical history: history of CT disease, malignancy, inflamm. bowel disease
- Smoking and occupational and environmental exposure
- Prior medication
How will a patient with interstitial lung disease appear on examination?
- cyanosis
- tachycardia
- tachypnoea
- finger clubbing
- fine end inspiratory crackles
- Signs of R heart failure like peripheral oedema
How might you investigate a patient with ILD?
- X ray
- Lung function test
- HRCT
- May need a surgical lung biopsy
What chemicals/molecules could cause occupational/environmental exposure ILD?
- Inhaled organic dust; stone and coal dust and asbestos fibres
- Silicates
- Carbon
- Metals
- Inhaled agents other than inorganic/organic: gases, fumes, aerosols, chemicals, etc.
What is the name for the ILD conditions caused by stone dust, coal dust and asbestos fibres?
What is the brief pathophysiology?
Stone dust: silicosis
Coal dust: pneumoconiosis
Asbestos Fibres: asbestosis
- particles <7mm across reach terminal bronchioles and alveolar ducts
- Scavenged by macrophages
- Trigger release of mediators causing inflammation, tissue damage and scarring (fibrosis)
What could form in the lungs as a result of asbestos?
What cancers are you at risk of?
Pleural plaques, benign pleural effusion, diffuse pleural thickening
Mesothelioma, broncho-carcinoma
Which individuals are more at risk of asbestos exposure, how long can it take for symptoms of an asbestos-related condition to appear?
Carpenters, plumbers, electricians, painters, builders
10-40 years
What is hypersensitivity pneumonitis?
What can occur in the acute and chronic versions?
Extrinsic allergic alveolitis: inhalation of organic or inorganic antigens can trigger an immune response that results in alveolitis
Acute: produces an influenza like illness 4-9 hours after with dry cough and breathlessness on exertion
Chronic: long term exposure to antigens leads to dry cough and breathlessness for months-years
What are 2 common antigens that trigger hypersensitivity pneumonitis?
- Farmer’s lung; mouldy hay
2. Bird fancier’s lung; antigens from pigeons and budgies
What are some treatment/management options for hypersensitivity pneumonitis?
- Bronchoalveolar lavage
- Surgical lung biopsy
- HRCT
- Avoidance and steroids
What is sarcoidosis?
Which organs are commonly affected?
Multi-system granulomatous disorder of unknown cause but with genetic predisposition
Can affect any organ; but commonly lungs, skin and eyes
What is the epidemiology of sarcoidosis?
Highest in young-middle aged, afro Caribbean, Asians and whites, female
How does sarcoidosis initially present and what will a biopsy show?
Asymptomatic initially, a biopsy will show non-caseating granulomas
List 3 reasons someone may acquire treatment-related ILD
- Certain drugs like methotrexate
- Radiotherapy
- Chemotherapy
How might you recognize sarcoidosis on an X ray?
Bilateral hilar lymphadenopathy, pulmonary infiltration
How would sarcoidosis appear on a lung function test?
Obstructive or restrictive
Name 2 systemic CT diseases that can lead to ILD
- Rheumatoid arthritis
2. Scleroderma
What is idiopathic interstitial lung disease?
What group of inflammatory disorders of the interstitium can it give rise to?
Inflammation of interstitial tissues with unknown cause
Can give rise to idiopathic interstitial pneumonias (all have differing clinical, histology features and prognosis)
What is the most common Idiopathic interstitial pneumonia disorder? State a brief pathophysiology
IFP/UIP
Progressive inflammatory condition of lung
1. Increased number of activated alveolar macrophages
2. activated macrophages attract neutrophils and eosinophils which reactivate oxidant species and proteases
3. result is tissue destruction and fibrosis
Which layer of the pleural seal has pain innervation?
The parietal pleura
When would production of pleural fluid increase?
- Increase hydrostatic pressure in capillaries
- Increased permeability of capillaries
- Decreased oncotic pressure
How is pleural fluid produced and absorbed?
Produced by filtration of capillaries and absorbed by lymphatic drainage
List 3 causes of transudate
Heart failure, liver failure (hypoproteinemia), renal failure
List 3 causes of exudate
Cancer, infection, CT disease
What is the name of a primary pleural malignancy? How does it present and what commonly causes this?
Mesothelioma, commonly asbestos exposure and with pain and breathlessness
What is Pectus carinatum and pectus excavatum?
What part of the breathing cycle will these affect?
Congenital chest wall diseases: pectus deformities
Pectus carinatum: protrusion of the anterior chest wall (pigeon chest)
Pectus excavatum: funnel chest (which can cause kyphosis, scoliosis and a muscular dystrophy)
More restrictive diseases and so affect inspiration
How would you get a chest wall disease?
Congenital or acquired
How would you acquire a chest wall disease?
- Trauma most common; can cause pneumothorax and lung collapse
- Anklyosing spondylitis: spinal arthritis
- Kyphosis and scoliosis
