Interstitial and Occupational Lung Disease Flashcards
describe interstitial disease
any disease process affecting lung interstitium (alveoli, terminal bronchi)
interferes with gas transfer
restrictive lung patterns
can be;
acute
episodes
chronic - part of systemic disease, exposure to agents (drug, dust, bird feathers) or idiopathic
describe symptoms of restrictive lung disease
breathlessness
dry cough
describe sarcoidosis
granulomatous (tpye IV hypersensitivity) disease of unknown cause
multiple system involvement;
common - lungs, lymph nodes, joints, liver, skin, eyes
uncommon - kidneys, brain, nerves, heart
non-caseating granuloma of unknown aetiology - probable infective agent in susceptible individual
imbalance of immune system with type IV (cell mediated) hypersensitivity
less common in smokers
describe types of sarcoidosis - acute
erythema nodosum bilateral hair lymphadenopathy arthritis uveitis, parotitis fever self-limiting condition
describe types of sarcoidosis - chronic
lung infiltrates (alveolitis) skin infiltrations peripheral lymphadenopathy hyper-calcaemia other organs - renal, myocardial, neurological, hepatitis, splenomegaly - oral steroids if vital organ effected
describe differential diagnosis of sarcoidosis
TB
lymphoma
carcinoma
fungal infection
describe tests for sarcoidosis
CXR
high resolution CT - peripheral nodular infiltrate
tissue biopsy - transbronchial, skin, lymph nodes, non caseating granuloma (indication of TB)
pulmonary function - restrictive defect due to lung infiltrates
blood tests;
angiotensin converting enzyme (ACE) level as activity marker (not a diagnostic test)
raised calcium
increased inflammatory markers
describe treatment of sarcoidosis - acute
no treatment
steroids if vital organ effected - impaired lung function, heart, eyes, brain, kidneys
describe treatment of sarcoidosis - chronic
oral steroids
immunosuppession - azathioprine, methotrexate, anti-TNF therapy)
describe hypersensitivity pneumonitis (extrinsic allergic alveolitis)
type III hypersensitivty (immune complex disposition) reacction to antigen lymphocytic alveolitis
caused by; thermophilic actinomycetes - farmers lung, malt workers, mushroom workers avian anitgens - bird fanciers lung drugs - gold, bleomycin, sulphasalazine no cause in ~30% cases
describe acute sarcoidosis - symptoms, signs, treatment
can be acute or chronic
acute;
cough, breathless, fever, myalgia - symptoms hours after acute exposure
signs - +/- pyrexia, crackles (no wheeze), hypoxia, CXR - widespread pulmonary infiltrates
treatment - oxygen, steroids, antigen avoidance, anti-fibrotic therapy in cases of progressive fibrosis (prifenidone, nintedanib)
describe chronic sarcoidosis - symptoms, signs, tests, diagnosis and treatment
chronic - repeated low does antigen exposure over time (years)
symptoms - progressive breathlessness and cough
signs - crackles, clubbing unusual
tests - CXR shows pulmonary fibrosis (upper zones), Pulmonary function tests - restrictive defect (low FEV1 and FVC –> high or normal ratio, low gas transfer - TLCO)
diagnosis - history of exposure, precipitins (IgG antibodies to guilty antigen), lung biopsy if not
treatment - remove antigen exposure, oral steroids if breathless or low gas transfer
describe idiopathic pulmonary fibrosis (Cryptogenic fibrosing alveolitis)
most common interstitial lung disease idiopathic disease; imbalance of fibrotic repair system ? related to gastric reflux not an inflammatory disease more common in smokers
secondary causes;
rheumatoid, SLE, systemic sclerosis, asbestos
drugs - amiodarone, busulphan, bleomycin, penicillamine, nitrofurantoin, methotrexate
pathology - usual interstitial pneumonia pattern (UIP), heterogenous fibrosis in alveolar walls with fibroblastic foci and destruction of architecture causing honeycombing. Inflammation minimal
describe clinical presentation of IPF
progressive breathlessness over several years, dry cough
finger clubbing, bilateral fine inspiratory crackles
describe tests for IPF
pulmonary function test - restrictive defect - reduced lung volumes and low gas transfer
CXR - bilateral infiltrates
CT - reticulondular fibrotic shadowing, worse at lung bases and periphery, traction bronchiectasis, honeycombing cystic changes
lung biopsy - not necessary if CT diagnostic
describe differential diagnosis of IPF
exclude occupational disease (asbestos, silicosis)
connective tissue disease (RhA, scleroderma, siogrens disease, SLE)
left ventricular failure
sarcoidosis
extrinsic allergic alveolitis
always ask about occupation, pets and drug history
describe treatment of IPF
steroids and immunosuppressants do not change course of disease
new antibiotics - pirfenidone and nintedanib - slow down disease progression (expensive and side effects)
antifibrotic therapy does no reverse fibrosis but slows progression
oxygen is hypoxic
lung transplant in young patients
many patients progress to respiratory failure, 4 years survival rate from diagnosis
describe coal workers pneumoconiosis
simple pneumoconiosis - CXR abnormality only - egg-shell calcification of hilar nodes (no impairment of lung function, associated with COPD)
complicated pneumoconiosis - progressive massive fibrosis. Restrictive pattern with breathlessness
chronic bronchitis (coal dust and smoking)
Caplan’s syndrome - rheumatoid, pneumoconiosis (pulmonary nodules)
describe silcosis
15-20 years exposure to quartz (mining, foundry workers, glass workers, boiler workers)
simple pneumoconiosis
chronic silicosis - restrictive pattern, pulmonary fibrosis
describe asbestos - related lung disorders - pleural disease
benign pleural - asymptomatic
acute asbestos pleuritis - fever, pain, bloody pleural effusion (benign condition)
pleural effusion and diffuse pleural thickening - restrictive impairment
malignant mesothelioma - incurable pleural cancer. Presents with chest pain and pleural effusion. No treatment
describe asbestos - related lung disorders - pulmonary fibrosis
asbestosis; heavy prolonged exposure diffuse pulmonary fibrosis and restrictive defect asbestos bodies in sputum asbestos fibres in lung biopsy
describe asbestos - related lung disorders - bronchial carcinoma
asbestos multiplies risk in smokers
