Interstitial and Occupational Lung
Disease
Dr Robin Smith
Dept of Respiratory Medicine
Interstitial Disease
• Any disease process affecting lung interstitium (ie
alveoli, terminal bronchi).
• Interferes with gas transfer
• Restrictive lung pattern (may also have some
airway obstruction if small airways involved)
• Symptoms: breathlessness, dry cough
Interstitial Lung Disease
Classification
• Acute
• Episodic
• Chronic - part of systemic disease
- exposure to agent (e.g. drug, dust etc)
- idiopathic
Acute ILD
• Infection
• Allergy
• Toxins
- usually viral
- eg drug reaction
- cytotoxic drugs, toxic fumes
e.g. chlorine
• Vasculitis
- eg Wegener’s granulomatosis,
Churg-strauss, SLE, Goodpasture’s syndrome
• ARDS
- trauma, sepsis
Episodic ILD
•
•
•
•
Pulmonary eosinophilia
Vasculitis (Churg-Strauss, Wegener’s, SLE)
Extrinsic Allergic Alveolitis
Cryptogenic Organising Pneumonia
Chronic ILD as part of systemic disease
• Connective Tissue Disease (eg Rheumatoid arthritis,
SLE, Systemic Sclerosis, Ankylosing Spondylosis)
• Vasculitis (Churg-Strauss, Wegener’s, SLE)
• Sarcoidosis
• Cancer (lymphoma, lymphangitis carcinomatosis)
• Miscellaneous - tuberose sclerosis, lipid storage
disorders, neurofibromatosis, amyloidosis, miliary
TB, bone marrow transplant)
Chronic ILD - exposure to foreign agent
• Fibrogenic inorganic dusts - coal, silica, asbestos,
aluminium,
• Non-fibrogenic dust - siderosis (iron), stannosis (tin),
baritosis (barium)
• Granulomatous/fibrogenic - berylliosis
• Organic dusts - Farmer’s lung (Microsporylium),
bagassosis (mouldy sugar cane), Bird fancier’s lung (feather and dropping antigen)
Chronic ILD - idiopathic
• Idiopathic Pulmonary Fibrosis (IPF) – also known as
Cryptogenic fibrosing alveolitis (CFA)
• Cryptogenic organising pneumonia (COP)
• Sarcoidosis
• Alveolar proteinosis
• Lymphangioleiomyomatosis (LAM)
• many other rarer causes
SARCOIDOSIS
•
Multiple-system disease:
common
- lungs, lymph nodes, joints, liver, skin, eyes
less common - kidneys, brain, nerves, heart
•
non-caseating granuloma of unknown aetiology: probable infective agent in
susceptible individual. Imbalance of immune system with type 4 (cell mediated)
hypersensitivity
Types
• Acute sarcoidosis:
erythema nodosum, bilateral hilar lymphadenopathy, arthritis, uveitis, parotitis,
fever.
•
Chronic sarcoidosis: lung infiltrates (alveolitis), skin infiltrations, peripheral
lymphadenopathy, myocardial, neurological, hepatitis, splenomegaly,
hypercalcaemia.
SARCOIDOSIS
Differential diagnosis = TB (tuberculin test -ve), Lymphoma, Carcinoma, fungal
infection.
•
•
Chest X-ray (BHL), CT scan of lungs (peripheral nodular infiltrate)
Tissue biopsy (eg transbronchial, skin, lymph node)  non-caseating
granuloma.
•
•
Pulmonary function: Restrictive defect due to lung infiltrates.
Blood test:
Angiotensin
Converting
Enzyme
(ACE)
activity marker (NOT diagnostic test).
- raised calcium
- increased inflammitory markers
levels
•
Acute: self-limiting condition.
•
Chronic: oral steroids if vital organ affected (eg lung, eyes, heart, brain).
as
SARCOIDOSIS
Treatment
• Acute:
self-limiting condition - usually no treatment
Steroids if vital organ affected (eg impaired lung
function, heart, eyes, brain, kidneys)
• Chronic:
oral steroids usually needed
Immunosuppression (eg azathioprine, methotrexate)
monitor chest X-ray and pulmonary function for several years
often relapses
Erythema Nodosum-Sarcoidosis
Iritis due to sarcoidosis
Bilateral hilar lymphadenopathy
and lung infiltrares -Sarcoidosis
EXTRINSIC ALLERGIC ALVEOLITIS I
•
Type III hypersensitivity (Immune complex deposition) reaction to antigen 
lymphocytic alveolitis (hypersensitivity pneumonitis).
•
Aetiology: Microsporylium (farmers lung, malt workers, mushroom workers),
avian antigens (bird fanciers lung), drugs (gold, bleomycin, sulphasalazine)
•
Can be ACUTE or CHRONIC
•
ACUTE: cough, breathless, fever, myalgia - several hours after acute exposure
(flu-like illness)
Signs: +/- pyrexia, crackles (no wheeze!), hypoxia
CxR: widespread pulmonary infiltrates
Treatment: oxygen, steroid and antigen avoidance
EXTRINSIC ALLERGIC ALVEOLITIS II
CHRONIC:  repeated low dose antigen exposure over time 
progressive breathlessness and cough
• Signs: may be crackles, clubbing is unusual
• CxR pulmonary fibrosis - most commonly in the upper zones
• PFTs: restrictive defect (low FEV1 & FVC, high or normal ratio,
low gas transfer - TLCO)
• Diagnosis: history of exposure, precipitins (IgG antibodies to
guilty antigen), lung biopsy if in doubt.
• Treatment: remove antigen exposure, oral steroids if breathless or
low gas transfer.
Extrinsic allergic alveolitis[Avian]
IDIOPATHIC PULMONARY FIBROSIS
(also known as Cryptogenic Fibrosing Alveolitis)
Most common interstitial lung disease
•
Clinical presentation: progressive breathlessness, dry cough
OE: clubbing, bilateral fine inspiratory crackles,
Ix: restrictive defect (reduced FEV1 and FVC with normal or raised
FEV1/FVC ratio, reduced lung volumes, low gas transfer CxR - bilateral
infiltrates;
CT scan - reticulonodular fibrotic change, worse at the lung bases. The
presence of “ground-glass” suggests reversible alveolitis; fibrosis is
irreversible.
•
Causes:
amiodarone,
methotrexate).
Primary (Idiopathic)
Secondary (eg rheumatoid, SLE, systemic sclerosis, drugs busulphan,
bleomycin,
penicillamine,
nitrofurantoin,
IDIOPATHIC PULMONARY FIBROSIS II
•
Differential diagnosis = exclude occupational disease (asbestosis, silicosis),
mitral valve disease, left ventricular failure, sarcoidosis, extrinsic allergic
alveolitis.
•
Ask about occupation (in depth), pets and drugs
•
Diagnosis: combination of history, examination and radiology tests
•
If the presentation is atypical then lung biopsy (either transbronchial or
thoracascopic) is needed
•
Pathology: chronic inflammatory infiltrate (neutrophils and fibrosis in alveolar
walls ± intra-alveolar macrophages.
IDIOPATHIC PULMONARY FIBROSIS III
•
Treatment: not clear if influences course of disease
oral steroids ± immunosuppressive drugs (eg azathioprine combined with Nacetyly cisteine) worth trying if patient is <75 years and evidence of acute
inflammation on CT scan - some response in 30%.
NB treatment is aimed as slowing future progression rather than reversing
established fibrosis.
Oxygen if hypoxic.
Lung transplantation in young patients
Future treatments:
?Anti-fibrotic agents
?anti-TNFα
pulmonary artery vasodilators
•
Prognosis: most patients progress into respiratory failure and are dead within 5
years
DIP-pre steroids
Fibrosing Alveolitis
Lymphocytic alveolitis and intralumenal macrophages
COAL WORKERS PNEUMOCONIOSIS
• Simple pneumoconiosis - chest X-ray abnormality only (no
impairment of lung function - often associated with
chronic obstructive pulmonary disease).
• Complicated pneumoconiosis - progressive massive fibrosis
 restrictive pattern with breathlessness.
• Chronic bronchitis (coal dust + smoking).
• Caplan’s syndrome
(pulmonary nodules).
-
rheumatoid
pneumoconiosis
SILICOSIS
• 15-20 years exposure to quartz (eg mining, foundry
workers, glass workers, boiler workers).
• Simple pneumoconiosis - chest X-ray abnormality only
(egg-shell calcification of hilar nodes).
• Chronic silicosis - restrictive pattern, pulmonary fibrosis.
Coal workers progressive massive fibrosis
Coal workers progressive massive fibrosis
Baritosis
ASBESTOS-related lung disorders
•
Mining, construction, shipbuilding, boilers and piping, automotive components
(eg brake linings).
•
Pleural disease 1- Benign pleural plaques - asymptomatic
2- Acute asbestos pleuritis - fever, pain, bloody pleural effusion
3- Pleural Effusion and Diffuse pleural thickening - restrictive impairment
4- Malignant Mesothelioma - incurable pleural cancer. Presents with chest pain
and pleural effusion. No available treatment - fatal within two years.
•
Pulmonary Fibrosis - “Asbestosis” - heavy prolonged exposure. Diffuse
pulmonary fibrosis and restrictive defect. Asbestos bodies in sputum. Asbestos
fibres in lung biopsy.
•
Bronchial carcinoma - asbestos multiplies risk in smokers
Asbestosis
Asbestos pleural plaques
and Bronchial Ca
Pleural effusion
due to mesothelioma
OCCUPATIONAL ASTHMA
• Sensitising agents - high molecular weight (eg bakers,
enzymes, gums, latex) - low molecular weight (eg
isocyanates, wood dust, glutaraldehyde, solder, flux, dye,
adhesives, drugs).
• Diagnosis: RAST test, provocation testing, PEFR at
home/work.
• Reactive airway dysfunction syndrome - acute episode of
toxic gas or fume inhalation (eg chlorine or sulphur
dioxide)

followed
by
persistent
bronchial
hyperreactivity.
Useful clinical & X-ray
teaching sites
hhhttp://www.radiology.co.uk/srs-x/index.htm
guidelines)
http://www.brit-thoracic.org.uk/clinical-information/interstitiallung-disease-(dpld)/interstitial-lung-disease-(dpld)guideline.aspx