Restrictive Lung Disease Flashcards
What does restrictive lung disease mean?
Diseases of the lung itself (alveoli & interstitium) that restrict lung expansion due to stiffness
What are key tests in the diagnosis of RLD
FVC/FEV1 ratio (>70) and DLCO (<80%)
What does DLCO measure?
Gas diffusion across alveolar-arterial barrier
Give some structural, neural and interstitial causes of RLD…
- kyphosis-scoliosis, obesity, diaphragmatic palsy
- motor-neurone disease
- mesothelioma, pleural ef
What is a common complication of RLD
Hypoventilation
True/False:
Interstitial Lung Disease is the most common type of RLD?
True
What diseases are encompassed under ‘Acute ILD’ category?
Respiratory Distress Syndrome, Alveolitis
What diseases are encompassed under ‘Chronic ILD’?
Idiopathic Pulmonary Fib, Hypersensitivity Pneumonitis, Coal-workers Pneumoconiosis, Asbestosis, Silicosis (among others)
What characterises Chronic ILDs?
Fibrosis
What is the epidemiology of Idiopathic Pulmonary Fibrosis (IPF)
males more at risk, over 50 years of age
What is IPF?
repeated injury of alveolar epithelium resulting in fibrosis of tissue.
What is the pathophysiology of IPF?
Repeated injury to alveolar epi > uncontrolled healing leading to hyper production of fibroblasts > loss of structural integrity of lung parenchyma = stiffening
Aetiology of IPF?
unknown. may be due to inhalation insults, viruses, drugs, GORD*, genetic
What specific drug may be responsible for IPF?
methotrexate
What are the presenting symptoms of IPF?
- progressive dyspnoea & dry cough, wt loss
- clubbing, bi-basal inspiratory crackles, cyanosis
Ix for IPF…
PFTs, blood tests, CXR, HRCT, bronchoalveolar lavage
What could be seen on CXR and HRCT if IPF is present?
CXR: bilateral infiltrates, many lines and dots
HRCT: honeycombing
What bloods would be done for IPF?
RF, ANA (to exclude rheumatic disease) , ABGs
What are ‘many lines and dots’ expressed as on a CXR?
Reticulonodular pattern
Tx for IPF…
transplant, anti-fibrotic therapy, supportive (O2, pulmonary rehab)
What are complications of IPF?
cor pulmonale (RVHF), resp failure (CO2 retention)
What is the prognosis for IPF?
2-4 years so very poor :(
life expectancy shorter after acute exacerbations
What is the other name for Hypersensitivity Pneumonitis?
Extrinsic Allergic Alveolitis
What are the classes of HP?
Acute, subacute, chronic
What type of hypersensitivity reaction is subacute HP?
Type 3
What is HP?
Allergic reaction affecting small airways and alveoli in response to an inhaled antigen
What is the pathophysiology of HP?
Chronic infiltrate which triggers an immunological and inflammatory response which activates macrophages resulting in progressive development of pulmonary fibrosis
What are the triggers for HP…
Bacterial: farmer’s lung, humidifier’s lung
Protein: Bird-fancier’s lung
Fungi: Malt-worker’s Lung, mushroom, cheese washer, winemaker
What characteristic does bacteria responsible for HP usually possess?
it is usually Thermophilic (thrives in high ºC)
What are the general presenting symptoms for HP?
dyspnoea & dry cough, inspiratory wheeze, bilateral crackles
Discuss acuteHP in terms of symptoms and resolution…
fever, rigors, malaise, cough & dyspnoea, hypoxia
comes on: 4-6hrs after exposure
resolves: 24-48hrs after exposure
Discuss subacute HP in terms of symptoms and resolution…
wt loss *
comes on: low level/ intermittent exposure
resolves: within weeks
Discuss chronic HP in terms of symptoms and resolution…
wt loss, dyspnoea & cough, cor pulmonale
comes on: repeated exposure
resolves: never
Ix for HP…
CXR, HRCT, PFTs, lung biopsy
True/False:
CXR for acute HP shows apex pulmonary fibrosis
False
CXR for acute HP shows infiltrates, for chronic HP shows apex PFib
Tx for HP…
acute: O2, oral steroids, anti-fib therapy
chronic: oral steroids, avoid antigen
True/False:
Prognosis for HP is good
True
What are the 3 main conditions encompassed by occupational lung disease?
Silicosis, Coal-workers pneumoconiosis, Asbestosis
Is Pneumoconiosis common?
yes
Is silicosis common?
no
What are the 4 different types of pneumoconiosis?
simple pneumoconiosis, complicated pneumoconiosis (progressive massive fibrosis), co-existing bronchitis pneumoconiosis, caplan’s syndrome (rheumatoid pneumoconiosis)
True/False:
Hypersensitivity types 1,2,3 are present in simple pneumoconiosis?
True
What are the 2 classes of silicosis and describe them?
simple (asymptomatic with CXR abnormalities), chronic (restrictive pattern & p fib occurs)
How can asbestos present in the pleura? (5 points)
Asbestos bodies, pleural plaques, defuse pleural thickening, pleural effusion/ acute asbestos pleuritis (bloody pleural ef), mesothelioma
How can asbestos present in other ways other than pleural infiltration?
Asbestosis (interstitial fibrosis), asbestos related bronchial carcinoma
What is CW pneumoconiosis?
small dust particles that are retained in the small airways and alveoli of lungs
What is silicosis?
inhalation of silica
What is asbestosis?
fibrosis of lungs due to asbestos exposure
What is mesothelioma?
tumour of lining of the lung- mix of sarcoma & carcinoma cells
What is pathophysiology of occupational lung diseases (OLD)…
- CWP: dust in lungs causes surrounding tissue to react and initiate an inflammatory response= fibrosis, emphysema & airway damage
- Silicosis: silica is toxic to macrophages initiating rapid fibrogenesis
- Asbestosis: inflammatory reaction to asbestos bodies resulting in diffuse interstitial fibrosis
Triggers of OLD…
CWP: coal dust
Silicosis: long term exposure to stone (e.g. sandblasting)
Asbestosis: long term exposure to asbestos fibres e.g. building site
True/False:
Bent asbestos fibres are more dangerous that straight asbestos fibres?
False!
Presenting symptoms of CWP…
dyspnoea & dry cough, black sputum
Presenting symptoms of silicosis…
dyspnoea & dry cough
Presenting symptoms of asbestosis…
progressive dyspnoea & cough, clubbing, basal inspiratory crackles
Presenting symptoms of mesothelioma…
effusion, chest wall pain, dyspnoea, wt loss,
OLD ix…
PFTs, CXR, HRCT
CWP CXR findings..
many round opacities in upper zones
silicosis CXR findings..
thin streaks of calcification around hilar lymph nodes, opacities in upper lung
Asbestosis CXR findings…
honeycombing and streaky shadowing
Ix for mesothelioma…
thorascopic pleural biopsy, thoracentesis*, CXR
Tx for OLD..
CWP: avoid exposure, treat bronchitis
Silicosis: avoid exposure
Asbestosis: corticosteroids
True/False:
A complication of asbestosis is inc risk of cancer?
True
Tx for mesothelioma…
surgery, chemo, palliative, pleurodesis (obliteration of pleural cavity)
Prognosis for OLD?
All involve pulmonary fibrosis so bad prognosis
Prognosis for mesothelioma?
2 years
Is compensation available for OLD and for HP?
Yes!