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.
