Interstitial Lung Disease Flashcards
What are the 2 main symptoms of interstitial lung disease?
Breathlessness and dry cough.
What groups divide interstitial lung diseases based on time?
Acute, episodic or chronic.
What are the 4 groups of interstitial lung diseases?
- ILD of known cause.
- Idiopathic interstitial pneumonia.
- Granulomatous ILDs e.g. sacroidosis, EAA.
- Other forms e.g. LAM, HX.
What type of hypersensitivity reaction is sarcoidosis and what is its cause?
Type 4 (granulomatous), unknown cause.
What systems are involved in sarcoidosis?
Common: lungs, lymph nodes, joints, liver, skin, eyes. Less common: kidneys, brain, nerves, heart.
What type of granuloma is present in sarcoidosis?
Non-caseating granuloma.
What is a possible cause of sarcoidosis?
Probable infective agent in susceptible individual due to imbalance of immune system.
What group is sarcoidosis less common in?
Smokers.
What are the signs and symptoms of acute sarcoidosis?
Erythema nodosum, bilateral hilar lymphadenopathy, arthritis, uveitis, parotitis (inflammation of the parotid gland), fever.
What are the signs and symptoms of chronic sarcoidosis?
Lung infiltrates (alveolitis), skin infiltrations, peripheral lymphadenopathy, hypercalcaemia, other organs.
What are the differential diagnoses of sarcoidosis?
TB, lymphoma, carcinoma, fungal infections.
What are the tests and investigations for sarcoidosis and what are you looking for?
CXR (bilateral hilar lymphadenopathy), lung CT scan (peripheral nodular infiltrate), tissue biopsy (e.g. transbronchial, skin, lymph node, non-caseating granuloma), pulmonary function (restrictive), blood test (angiotensin converting enzyme levels as activity marker, raised calcium, increased inflammatory markers).
What is the treatment for acute sarcoidosis?
Self-limiting so usually no treatment, steroids if vital organ affected.
What is the treatment for chronic sarcoidosis?
Oral steroids usually needed if vital organ affected. Immunosuppression e.g. azathioprine, methotrexate, anti-TNF therapy.
In sarcoidosis why would you monitor CXR and pulmonary function for several years?
There are often relapses.
What type of hypersensitivity reaction is extrinsic allergic alveolitis (hypersensitivity pneumonitis)?
Type III (immune complex deposition), reaction to antigen (lymphocytic alveolitis).
What antigens cause EAA?
Thermophilic actinomyecytes (farmers, malt workers, mushroom workers), avian antigens (bird fanciers), drugs (gold, bleomycin, sulphasalazine),
What are the symptoms and signs of acute EAA?
Symptoms: cough, breathlessness, fever myalgia (all may occir several hours after exposure). Signs: pyrexia, crackles (no wheeze), hypoxia.
What would you see on CXR with acute EAA?
Widespread pulmonary infiltrates.
What is the treatment for acute EAA?
Oxygen, steroids and antigen avoidance.
What would cause chronic EAA?
Repeated low dose antigen exposure over time.
What are the symptoms and signs of chronic EAA?
Symptoms: progressive breathlessness and cough. Signs: Crackles, clubbing is unusual.
Where is pulmonary fibrosis most often seen in a CXR of chronic EAA?
The upper zones.
What would pulmonary function tests of chronic EAA show?
Restrictive defect, low TLCO [transfer factor for the lung for carbon dioxide].
How would you come to the diagnosis of chronic EAA?
History of exposure, precipitins (IgG antibodies to guilty antigen), lung biopsy if in doubt.
What is the treatment for chronic EAA?
Remove antigen exposure, oral steroids if breathless or low gas transfer.
What causes idiopathic pulmonary fibrosis?
Imbalance of fibrotic repair system (cause of this is unknown).
Give some examples of secondary causes of pulmonary fibrosis.
Rheumatoid arthritis, SLE (systemic lupus), systemic sclerosis, asbestos.
What drugs can cause pulmonary fibrosis?
Amiodarone, busulphan, bleomycin, penicillamine, nitrofurantoin, methotrexate.
What are the signs and symptoms of IPF?
Symptoms: progressive breathlessness (several years), dry cough. Signs: finger clubbing, bilateral fine inspiratory crackles.
What would show up in pulmonary function tests and CXR in IPF?
PFTs - restrictive defects, reduced lung volumes and low gas transfer. CXR - bilateral infiltrates.
What would be seen in a CT scan of IPF?
Reticulonodular fibrotic shadowing, worse at the lung bases and periphery. Traction bronchiectasis (alvoeli pull airways apart). Honey combing cystic changes.
When would a lung biopsy not be necessary in IPF?
If CT scan diagnostic.
What is the differential diagnosis for IPF?
Occupational diseases, connective tissue disease (RhA, scleroderma, Sjogrens disease, SLE), LVF, sarcoidosis, EAA.
What is the pathological structure of IPF?
Usual intersitial pneumonia patter (UIP). Heterogenous fibrosis in alveolar walls with fibroblastic foci and destruction of architecture causing honeycombing. Minimal inflammation.
What is the treatment for IPF?
Antifibrotic drugs (pirfenidone and nintedanibe), slow down disease progression but very expensive and many side-effects.
Describe the pulmonary interstitium.
Alveolar lining cells, thin elastin-rich connective component containing capillary blood vessels.
What is the early stage of interstitial lung disease?
Alveolitis (injury with inflammatory cell infiltration).
What is the disease that has acute ILD?
Adult respiratory distress syndrome (ARDS).
What is the late stage of ILD characterised by?
Fibrosis.
What two types of biopsy are used in ILDs?
Transbronchial (special forceps used at bronchoscopy) and thoracoscopic (more invasive but more reliable and generated far more tissue).
What are the two commonest ILDs?
Granulomatous ILDs and idiopathic pulmonary fibrosis.
What is a sign on someone’s hands that they have IPF?
Finger clubbing.
What are the visible signs of IPF on the lungs?
Subpleural and basal fibrosis, inflammatory component variable, terminally lung structure replaced by dilated spaces surrounded by fibrous walls (honeycomb lung).
What pulmonary effects may there be in connective tissue disease?
Interstitial fibrosis (milder than IPF), pleural effusions, rheumatoid nodules.
