Interstitial lung disease

1. Interstitial lung disease Dr Felix Woodhead Consultant Respiratory Physician

2. Restrictive Defect • “Small lungs” vs “Wheezy lungs” (obstructive) • Intrinsic lung disease • abnormal radiology • ↓TLco • Extrathoracic restriction • normal radiology • normal TLco • ? ↑Kco (↓VA → TLco/VA ↑)

3. Extrathoracic Restriction • Soft tissues • Obesity • BMI not weight • Muscles • Diaphragm > intercostals • Orthopnoea • Sitting/lying FVC • Thoracic cage • Scoliosis > kyphosis • Pleural thickening

4. Radiological patterns 1 • Pleural effusions/mass • Dense white with no air bronchograms • Meniscus • Beware the supine effusion • Tumours • Spiculated & single (primary) vs round & multiple (mets) • May present as collapse • Collapse • Volume loss (shift of fissure/hilum) • Obliteration of adjacent silhouette

5. Alveolar space filling (≡ consolidation) • Fairly dense, with air bronchograms (patent airways) • Neutrophils ± microrganisms (pneumonia/organising pneumonia) • Eosinophils (eosinophilic pneumonia) • Blood (pulm haemmorhage) • Fluid (severe pulm oedema) • Surfactant (alveolar proteinosis) • Tumour (bronchoalveolar carcinoma – BAC)

6. Interstitial shadowing • Less dense than consolidation, dots and lines on CXR (reticulonodular) • Interstitial fluid (pulm odema) • Trapped lymph (lymphangitis carcinomatosis) • Inflammation/fibrosis • Interstitial lung disease • Diffuse parenchymal lung disease • Fibrosing alveolitis • “pulmonary fibrosis”

7. An approach to chest radiographs • Normal or abnormal? • If abnormal, how long? • If consolidation ?pneumonia • treat with antibiotics and repeat film 6-8/52 • If interstitial ?pulm oedema • Treat with diuretics and repeat film in a few days • Remember • Not all LRTIs are pneumonia (bronchitis/bronchiectasis) • Pulm oedema also seen with fluid resus and renal pts • Long-standing shadowing ?diffuse parenchymal lung disease

8. CT radiology terminologyFleischner Society: Glossary of Terms for Thoracic Imaging Radiology 2008 246 697-722

9. Myths about ILD • ILD is always pulmonary fibrosis • All ILD is the same • IPF and CFA is the same • There is no treatment for ILD

10. Respiratory Physiology • Restrictive spirometry • FEV1/FVC ratio ≥ 70% • FVC < 80% • But may have normal levels • Reduced TLC & RV • Reduced TLco & Kco • Serial change crucial

11. Interstitial Lung Disease caused by exposure to • Inorganic dusts • Pneumoconiosis • Asbestos, silica, coal dust • Organic dusts • Hypersensitivity pneumonitis (HP) • Prev called Extrinsic Allergic Alveolitis (EAA) • Birds, moulds etc etc • Drugs • Chemotherapeutic, methotrexate, amiodarone, others • www.pneumotox.com

12. ILD associated with Rheumatological Disease • Rheumatoid (RF, anti-CCP) • Systemic Sclerosis • Skin thickening ± internal organ fibrosis • Anticentromere (ACA), anti-topoisomerase 1 (ATA, prev Scl-70) • Idiopathic Inflammatory Myositis • Polymyositis (muscle) (Jo-1) • Dermatomyositis (skin and muscle) • SLE less commonly chronic ILD • acute pneumonitis & pleural disease more common • Sjögren’s Syndrome – Ro, La (SSA,SSB) • Less commonly present with ILD

13. Idiopathic Interstitial Pneumonitis • Cryptogenic Fibrosis Alveolitis (UK) • Idiopathic Pulmonary Fibrosis (USA and elsewhere) • Idiopathic disease usually does worse than secondary • Idiopathic disease phenotypically very variable • Idiopathic disease can be classified by surgical lung biopsy into the “IPs”

14. The “IPs” _ Interstitial Pneumonitis

15. 2002 ATS/ERS guidelines for Idiopathic Interstitial Pneumonia Am J Respir Crit Care Med 2002 Nicholson et al Am J Respir Crit Care Med 2000

16. Common DPLDs

17. Idiopathic Pulmonary Fibrosis (IPF) • Not interchangeable term for IIP (a subtype of it) • ?most common IIP • Relatively poor prognosis • Median survival 2 ½ years • Histology • Usual Interstitial Pneumonitis (UIP) when biopsied • Temporal and Spatial heterogeneity, not uniform • Radiology • Typical features: basal, peripheral honeycombing, little GGO • May have any appearance • Typical features – don’t need to biopsy, atypical – biopsy helpful

18. IPF CXR

22. (Cryptogenic) Organising Pneumonia - COP • Was also called Bronchiolitis-obliterans OP (BOOP) • Histology • Buds of organising inflammatory material in terminal bronchioles and airspaces • Characteristic lesion is the Masson body • Radiology • Consolidation ± GGO • May fibrose (?overlap with NSIP) • Usually responds well to steroids initially

26. Acute Interstitial Pneumonia

29. Hypersensitivity Pneumonitis • Prev called EAA • Variety of inhaled stimuli, can occur with drugs too • Check precipitins (IgG to allergens) • Histology • Lymphocytic • Poorly-formed granulomata • Bronchocentric • Radiology • Variety of appearances inc similar to IPF • Typical appearance mosaicism due to small airways involvement • BAL may be lymphocytic

32. Non-specific Interstitial Pneumonitis • A holding diagnosis • Histology • Appearances not typical for other diagnoses esp UIP • Temporally and spatially uniform in all samples • UIP in 1 and NSIP in 2 of 3 biopsies = UIP • Radiology • Typically more GGO than IPF • Often fibrosis • Varied • Clinical • Varied outcomes • May overlap with IPF, HP or COP? • Typical finding in CTD, many pts with idiopathic NSIP have CTD features

33. Smoking-related IIP • Respiratory Bronchiolitis • Histological appearance in ‘healthy smokers’ • Pigmented macrophages in terminal bronchioles • Clinical condition RB associated ILD (RBILD) • RBILD radiology similar to HP • BAL not lymphocytic • DIP • ‘Desquamative’ due to erroneous belief cells shed into alveoli • Diffuse collection of pigmented macrophages throughout alveoli • Radiologically typified by diffuse GGO • ?smoking related NSIP, Fibrosis and emphysema

37. Sarcoidosis • Often doesn’t need CT • Scadding CXR stages of limited use • CT appearances • Perihilar ‘Snow splats’ • Beading of fissures • Lymphadenopathy • May have atypical features • Histology typical • Noncaseating granulomata • Worth doing transbronchial and endobronchial biopsies • BAL often lymphocytic

40. ILD hints • CXRs tell you how long abnormality present and progress • History esp CTD features vital (trumps biospy etc) • CTs may be pathognomic • BAL helpful in HP/sarcoid • Phenotypically heterogeneous • Expert advise needed and MDT • Open biopsy may be helpful after expert advise • Treatment uncertain, ?trials