Restrictive Lung Disease Flashcards
Describe the nature of restrictive lung disease and compare it with obstructive diseases?
Restrictive lung diseases is where your FVC is reduced as you cannot expand your lungs properly. In restrictive problems your FEV1 should be normal or mildly decreased
In obstructive lung disease you should have a normal lung capacity however you cannot breath in and out properly due to obstruction therefore classically would have a reduced FEV1.
What is interstitial lung disease?
Disease that affects the lung parenchyma causing fibrosis and inflammation
Leads to stiff inelastic lung tissue that does not function effectively
What are the main categories of ILD?
Idiopathic pulmonary fibrosis
Hypersensitivity pneumonitis (extrinsic allergic alveolitis)
Occupational interstitial lung disease (pneumoconiosis)
Pulmonary fibrosis associated with connective tissue disease
Drug induced pulmonary fibrosis
Sarcoidosis
What are the symptoms of pulmonary fibrosis?
Pleuritic chest pain Dry Cough Exertional dyspnoea Weight loss Fatigue Arthralgia
What is the management of pulmonary fibrosis
Poor prognosis and limited management due to irreversible damage
Removal of underlying cause Abx if infection Home oxygen Stop smoking Physiotherapy Vaccinations
Lung transplant is only curative option
In hypersensitivity pneumonitis (extrinsic allergic alveolitis) what is the underlying hypersensitivity reaction?
It can be caused by a:
-Type III immune mediated hypersensitivity reaction
How can hypersensitivity pneumonitis be diagnosed?
Bronchoalveolar lavage with biopsy showing lymphocytes and mast cells
What are the common allergens associated with EAA? (7)
Farmer’s lung - one of the most common forms. Due to exposure to mouldy hay.
Bird-fancier’s lung - one of the most common forms. Due to exposure to avian proteins - eg, pigeons, parakeets.
Cheese-worker’s lung - exposure to cheese mould.
Malt worker’s lung - exposure to Aspergillus clavatus in mouldy malt.
Hot tub lung - exposure to Mycobacterium avium in poorly-maintained hot tubs
Chemical worker’s lung
Mushroom worker’s lung - exposure to thermophilic actinomycetes in mushroom compost
Describe the different presentations of EAA?
Acute:
- Symptoms occur 4-6 hours after exposure to antigen
- Flu-like illness with fever, chest tightness, dry cough, dyspnoea and malaise.
- Signs include bi-basal fine inspiratory crackles
- Severity often correlates with amount of exposure to an antigen
Subacute:
- Symptoms are less severe and more gradual in onset but similar in nature to acute presentations
- It can present as a recurrent pneumonia
Chronic:
- Few systemic symptoms other than weight loss and reduced exercise tolerance
- May present with exacerbations
What are the complications of repeated exposure to a causative organism in hypersensitivity pneumonitis?
Repeated inflammation causing fibrosis which may be permanent.
May develop respiratory failure due to the restrictive pathology.
May eventually develop cor pulmonale due to increased pulmonary vasculature resistance.
What is the main stay of treatment in EAA?
Avoidance/removal of antigens.
Acute reactions tend resolve spontaneously once the antigen has been removed.
In sub acute/chronic presentations steroids or other immunoupressive drugs may be needed.
What is asbestos poisoning?
Patients over 50
Worked in building industry or shipyards
Risk of disease proportional to exposure level
What is pneumoconiosis?
Disease of the lungs due to dust inhalation
Dust is toxic to macrophages and is inflammation response
Chronic exposure results in fibrosis
Risk of developing is related to dust exposure degree
What are the signs of pulmonary fibrosis?
Clubbing Resp distress Reduced chest expansion Bibasal fine end inspiratory crackles Can get expiratory wheeze Restrictive spirometry
What investigations are needed for pulmonary fibrosis?
Bloods
- FBC
- ANA
- RF
CXR
- decreased lung volume
- ground glass appearance
Spirometry- restrictive deficit and decrease TLCO
CT chest- honeycomb appearance
Lung biopsy if diagnosis uncertain
