interstitial lung disease (ild) mike mcfarlane (ct1) 12/5/12

Interstitial Lung Disease (ILD)

Mike McFarlane (CT1)

12/5/12

SLIME

What we’ll cover

• Definition• Different types of ILD• Pathophysiology• Presentation• Investigations• Management• Prognosis• Clinical Scenario• Summary

What we won’t...

• Other causes of restrictive lung defects– Thoracic cage defects

• Anything fun!!

Definition

• Interstitial lung disease is a diverse group of conditions affecting the pulmonary interstitium and/or the alveolar lumen

• Not airways!• The gas exchange parts and support tissue

Different types of ILD

• Idiopathic Pulmonary Fibrosis AKA: Cryptogenic fibrosing alveolitis, Usual

interstitial pneumonitis• Extrinsic Allergic Alveolitis

AKA: Hypersensitivity pneumonitis• Other Industrial lung diseases• Sarcoidosis

Pathophysiology• Cycles of inflammation, scarring and fibrosis leads to irreversible

damage to interstitial tissue• IPF: ?autoimmune• EAA:

– Farmer’s Lung: Micropolyspora faeni/ Aspergillus Fumigatus– Bird Fancier’s Lung: Avian serum proteins– Malt worker’s Lung: Aspergillus clavatus– Inhalation (humidifier) fever: Thermophillic actinomycetes

• Other “dust” diseases: (CABS)– Coal Workers Pneumoconiosis: Coal Dust

• Caplan’s Syndrome: CWP + Rheumatoid arthritis– Asbestosis: Asbestos– Beryllosis: Beryllium– Silicosis: Silicon

• Sarcoidosis: Multisystem autoimmune non-caseating granulomatous disorder

Presentation• Symptoms

– SOB on exertion– Lethargy– Dry cough– EAA – variability with work; IPF – progressive worsening– Sarcoid

• extrapulmonary features: – Anterior uveitis, conjunctivitis, arthralgia, erythema nodosum

– SMOKING, OCCUPATION, PETS

• Signs– Tachypnoeic– Clubbing – IPF, EAA– Cyanosis– Fine end-inspiratory creps

• IPF – more at bases• EAA – more at apices

Investigations• Bedside

– PEF , including work and home measurements– Sats, RR

• Blood tests– FBC, U&Es, LFTs, CRP, ESR– ABG - hypoxia– ANA and RF can be + in IPF– Calcium can be high in Sarcoidosis (serum ACE can be high but not

always!)• Imaging

– CXR – fine reticulonodular shadowing– CT

• Ground glass appearance• Honey combing

Investigations (2)• Special tests– Spirometry

• Restrictive defect i.e. Lung volume reduced. FVC reduced, FEV1 reduced in proportion (or slightly less). Therefore FEV1:FVC is normal or high!!

• TLCO (transfer factor) reduced – due to fibrosis of alveolar walls. Means a thicker barrier to gas exchange and less effective transfer

– N.B. Bronchoscopy, BAL, Biopsy

Reticulonodular shadowing

Honey combing and Ground Glass

Management• Conservative

– Smoking cessation– Change working conditions– Change work

• Medical – Depends on cause!!– IPF – very little besides oxygen! Steroids of little help– EAA – Steroids for acute episodes– Sarcoidosis – Only treat if extrapulmonary manifestations! Steroids

• Surgical– Lung transplant

Prognosis

• IPF – poor• EAA – depends on extent of disease and ability

to avoid the cause• Industrial lung disease - variable• Sarcoidosis - variable

Clinical scenario• A 64 year old gentleman presents to his GP with increasing SOB

over the last 6 months. • His exercise tolerance has reduced to the point where walking

to the corner shop makes him out of breath. • He also complains of a dry cough. • He has a past medical history of high blood pressure which is

managed with Ramipril. • He has never smoked and works as an office manager• He has no pets • On examination he is slightly short of breath with O2 sats 93%

on air and he has clubbing. Auscultation reveals bilateral basal fine end inspiratory crepitations and no wheeze.

Clinical scenario Cont

• What are your main differentials for this gentleman?

• How would you investigate this gentleman? • What is your management plan? • Will anything help?

Summary

• ILD is more complicated than it needs to be• Cardinal features are:– Fine end inspiratory creps – due to fibrosis– The cause of the fibrosis will usually be hinted at in

occupation or hobbies!– If no cause obvious its probably IPF

• Restrictive spirometry with reduced gas transfer• Treatment depends on cause – usual steroids

QUESTIONS

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