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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