Interstitial Lung Disease Flashcards
What is ILD?
A generic term to describe a number of conditions that primary affect the lung parenchyma in a diffuse manner.
They are characterized by chronic inflammation and/or progressive interstitial fibrosis.
What are some clinical features of ILD?
- Dyspnoea on exertion
- Non productive paroxysmal cough
- Abnormal breath sounds
- Fine end-inspiratory crackles
- Abnormal CXR/HRCT
- Restrictive spirometry with decreased DLCO
How can ILD be classified (3)?
Those with a known cause - Occupational (asbestosis, drugs (nitrofurantoin, amiodarone), hypersensitivity, infections (TB), GORD
Those associated with systemic disorders - Sarcoidosis, RA, SLE, UC, autoimmune thyroid
Idiopathic - Idiopathic pulmonary fibrosis, non specific interstitial pneumonitis
What is extrinsic allergic alveolitis (EAA)?
Repetitive inhalation of allergens in sensitized individuals provokes a hypersensitivity reaction which varies in intensity and clinical course depending on the antigen.
What happens in acute EAA?
Acute - Alveoli are infiltrated with acute inflammatory cells.
Symptoms - Fevers, rigors, myalgia, dry cough, dyspnoea, fine basal crackles
- Spontaneous settling in 1-3 days. Can recur.
What happens in chronic EAA?
Chronic - Granuloma formation and obliterative bronchiolitis
Symptoms - Finger clubbing, increasing dyspnoea, weight loss, exertional dyspnoea, type I respiratory failure, cor pulmonale.
What are some causes of EAA?
- Bird-fancier’s lung - Protein in pigeon droppings
- Farmer’s lung
- Malt worker’s lung
- Sugar worker’s lung
How do you investigate for acute EAA?
Bloods - FBC (neutrophilia), ESR, aBG’s serum antibodies
CXR - Upper zone mottling and consolidation
Lung function testings - Reversible restrictive defect, reduced gas transfer in acute attacks
What will a CXR show in chronic EAA?
- Upper zone fibrosis
- Honeycomb lung
How do you manage acute and chronic EAA?
Acute - Give O2, remove allergen, PO prednisolone
Chronic - Allergen avoidance, wear a facemask, long term steroids
What is the most common cause of ILD?
Idiopathic pulmonary fibrosis
How do you investigate for idiopathic pulmonary fibrosis?
Bloods - aBG, CRP, immunoglobulins, ANA, RA
Imaging - Reduced lung volume, bilateral lower zone reticulo-nodular shadows, honeycomb lung. HRCT is gold standard but shows simular changes.
BAL- Increased lymphocytes (good prognosis), increased neutrophils and eosinophils (bad prognosis)
Spirometry - Restrictive pattern
Lung biopsy - Will show usual interstitial pneumonia
What is the management for idiopathic pulmonary fibrosis?
Supportive - Oxygen, pulmonary rehabilitation, opiates, palliative care
- All patients considered for current clinical trials/lung transplantation
- High dose steroids not used unless diagnosis of IPF is in doubt
What is coal workers pneumoconiosis?
- Results from inhalation of coal dust particles over 15-20 years
- Ingested by macrophages which die, releasing enzymes and causing fibrosis
- Asymptomatic but coexisting chronic bronchitis is common
What is the CXR findings of coal workers pneumoconiosis?
Many round opacities, (1-10mm) especially in upper zone.
What is progressive massive fibrosis?
Due to progression of CWP, causing progressive dyspnoea, fibrosis and cor pulmonale.
What is silicosis?
Caused by inhalation of silica particles which are fibrogenic.
Jobs - Metal mining, stone quarrying, sandblasting, pottery/ceramic manufacture
What is asbestosis?
Caused by inhalation of asbestos fibres.
Progressive dyspnoea, clubbing, fine inspiratory crackles, pleural plaques, increased risk of bronchial carcinoma and mesothelioma
