Interstitial and Occupational Lung Diseases

Question 1

What is Interstitial Disease ?

Answer 1

Any disease process affecting lung interstitium (ie alveoli, terminal bronchi).
-Interferes with gas transfer
-Restrictive lung pattern
-Symptoms: breathlessness, dry cough

Interstitium is space between things

Question 2

What is sarcoidosis ?

Answer 2

Non-caseating granulomatous (type 4 hypersensitivity) disease of unknown cause
-probable infective agent in susceptible individual. Imbalance of immune system with type 4 (cell mediated) hypersensitivity

Multiple-system involvement:
-common; lungs, lymph nodes, joints, liver, skin, eyes
-less common; kidneys, brain, nerves, heart

Less common in smokers

Question 3

What are causes of acute sarcoidosis ?

Answer 3

erythema nodosum
bilateral hilar lymphadenopathy
arthritis
uveitis, parotitis
fever.

Question 4

What are causes of chronic sarcoidosis ?

Answer 4

lung infiltrates (alveolitis)
skin infiltrations
peripheral lymphadenopathy
hypercalcaemia
Other organs: renal, myocardial, neurological, hepatitis, splenomegaly

Question 5

What are differentials of sarcoidosis ?

Answer 5

TB (tuberculin test -ve), Lymphoma, Carcinoma, fungal infection.

Question 6

How is sarcoidosis tested for ?

Answer 6

Chest X-ray
CT scan of lungs; for peripheral nodular infiltrate
Tissue biopsy (eg transbronchial, skin, lymph node); non-caseating granuloma
Pulmonary function; Restrictive defect due to lung infiltrates (Decreased FVC and FEV1, maintained ratio)
Blood test:
-Angiotensin Converting Enzyme (ACE) levels as activity marker (NOT diagnostic test).
-raised calcium
-increased inflammatory markers

Question 7

How is acute sarcoidosis treated ?

Answer 7

Self-limiting condition; usually no treatment
-Steroids if vital organ affected (eg impaired lung function, heart, eyes, brain, kidneys, hypercalcaemia)

Question 8

How is chronic sarcoidosis treated ?

Answer 8

Oral steroids and Immunosuppression (eg azathioprine, methotrexate, anti-TNF therapy)`

Question 9

What is this ?

Answer 9

Painful red lesions

Question 10

What is this ?

Answer 10

Eye goes red

Question 11

What is this ?

Answer 11

Question 12

What is Hypersensitivity pneumonitis

Answer 12

Type III/IV hypersensitivity (Immune complex deposition) reaction to antigen; lymphocytic alveolitis

Causes:
-Thermophilic actinomycetes (farmers lung, malt workers, mushroom workers, other moulds)
-Avian antigens (bird fanciers lung)
-Drugs (gold, bleomycin, sulphasalazine)

No cause identified in about 30% of cases

Can be acute or chronic

Aka Extrinsic Allergic Alveolitis

Question 13

What are signs/symptoms of acute hypersensitivity pneumonitis and how is it treated ?

Answer 13

Cough, breathless, fever, myalgia
-Classically symptoms occur several hours after acute exposure (flu-like illness)
-Signs: +/- pyrexia, crackles (no wheeze!), hypoxia
-CxR: widespread pulmonary infiltrates

Treatment: oxygen, steroid and antigen avoidance

Acute is flu like illness for a few days, short period of time

Question 14

What is, and what are signs anf symptoms of chronic hypersensitivty pneumonitis ?

Answer 14

Repeated low dose antigen exposure over time (years), casuing 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.

Question 15

How is chronic hypersensitivity pneumonitis treated ?

Answer 15

Remove antigen exposure
-Oral steroids if breathless or low gas transfer.
-Immunosuppression eg Mycophenolate
-Anti-fibrotic therapy in cases of progressive fibrosis (Nintedanib)

Question 16

What is this ?

Answer 16

Question 17

How does idiopathic pulmonary fibrosis present ?

Answer 17

Clinical presentation: progressive breathlessness (several years), dry cough
OE: clubbing, bilateral fine inspiratory crackles
Ix: restrictive defect on PFT’s - reduced FEV1 and FVC with normal or raised FEV1/FVC ratio, reduced lung volumes, low gas transfer
CxR - bilateral infiltrates;
CT scan - reticulonodular fibrotic shadowing, worse at the lung bases, and periphery. Traction bronchiectasis. Honey-combing cystic changes.
Lung biopsy – not necessary if CT scan is diagnositic.

Question 18

What causes idiopathic pulmonary fibrosis ?

Answer 18

Aetiology not known
-Not an inflammatory disease
-More common is smokers

Question 19

What are secondary causes of pulmonary fibrosis ?

Answer 19

Other secondary causes of pulmonary fibrosis:
-rheumatoid, SLE, systemic sclerosis, asbestos (ILDs)
-drugs e.g, amiodarone, busulphan, bleomycin, penicillamine, nitrofurantoin, methotrexate

Some ILDs may progress and become fibrotic, like IPF, rare

Question 20

What are differentials for idiopathic pulmonary fibrosis ?

Answer 20

-Ocupational disease (asbestosis, silicosis)
-Connective tissue disease (RhA, scleroderma, Sjogrens Disease, SLE)
-Left ventricular failure
-Sarcoidosis
-Extrinsic allergic alveolitis

Ask about occupation (in depth), pets and drug history

Question 21

How is idiopathic pulmonary fibrosis diagnosed ?

Answer 21

Diagnosis: combination of history, examination and radiology tests (HRCT scan)
-If presentation or the HRCT scan is atypical then lung biopsy (either transbronchial or thoracascopic) may be needed

Question 22

What pathology findings are associated with idiopathic pulmoanry fibrosis ?

Answer 22

Usual Interstitial Pneumonia pattern (UIP) heterogenous fibrosis in alveolar walls with fibroblastic foci and destruction of architecture causing honeycombing. Inflammation is minimal.

Question 23

How is idiopathic pulmonary fibrosis treated ?

Answer 23

Steroids and immunosuppressants do not change course of disease
New antifibrotic drugs have emerged in recent years – PIRFENIDONE and NINTEDANIB – only therapies to have shown in randomised controlled trials to slow down disease progression BUT expensive, and many side-effects.
Antifibrotic therapy does not reverse fibrosis, merely slows progression. Add 2-3years to life expectancy

Oxygen if hypoxic.

Lung transplantation in younger patients (<65)

Question 24

What is the prognosis of idiopathic pulmonary fibrosis ?

Answer 24

Prognosis: most patients progress within a few years into respiratory failure
Median survival of IPF is 4 years from point of diagnosis without treatment

Question 25

What is simple pneumoconiosis ?

Answer 25

Definition: Early or mild form of pneumoconiosis Chest X-ray: Abnormalities only (small nodular opacities) Lung function: Usually normal, no significant impairment Associated conditions: Often occurs with chronic obstructive pulmonary disease (COPD)

Question 26

What is Complicated Pneumoconiosis (Progressive Massive Fibrosis)

Answer 26

Definition: Severe form with coalescence of nodules Features: Progressive fibrosis of lung tissue Chest X-ray: Large opacities (massive fibrosis) Lung function: Restrictive pattern, breathlessness Complications: Increased risk of pulmonary hypertension and respiratory failure

Question 27

What is Chronic Bronchitis ?

Answer 27

Cause: Usually coal dust exposure + smoking Features: Chronic productive cough, airway inflammation Lung function: Can lead to obstructive pattern on spirometry Notes: Often overlaps with simple pneumoconiosis in coal workers | Often coexists with pneumoconiosis

Question 28

What is Caplan’s Syndrome ?

Answer 28

Definition: Rheumatoid pneumoconiosis Features: Pulmonary nodules in patients with rheumatoid arthritis + pneumoconiosis Significance: Nodules may cavitate but lung function may remain relatively preserved initially

Question 29

What does silicosis cause and how does it arise ?

Answer 29

15-20 years exposure to quartz (eg mining, foundry workers, glass workers, boiler workers). Casuses Simple pneumoconiosis – few symptoms; chest X-ray abnormality (egg-shell calcification of hilar nodes). Chronic silicosis - restrictive pattern, pulmonary fibrosis.

Question 30

What diseases can asbestos cause ?

Answer 30

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. (diaphragmatc calcifications = think absestos, calcified plaque same colour as bone) Pulmonary Fibrosis - “Asbestosis” -Diffuse pulmonary fibrosis and restrictive defect due to heavy prolonged exposure. -Asbestos bodies in sputum. -Asbestos fibres in lung biopsy. Bronchial carcinoma - asbestos multiplies risk in smokers | Abestosis should mean pulmonary fibrosis due to asbestos

Question 31

What is this ?

Answer 31

Mesothelioma Encases lung all wat around; shrinks down lung, usually associaerd effusiosn