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R14 Respirology
Interstitial Lung Disease
Toronto Notes 2019
The CXR can be normal in up to 15% of patients with interstitial lung disease
Signs and Symptoms
• dyspnea,especiallyonexertion
• nonproductivecough
• crackles(dry,fine,end-inspiratory)
• clubbing(especiallyinIPFandasbestosis)
• featuresofcorpulmonale
• notethatsignsandsymptomsvarywithunderlyingdiseaseprocess
■ e.g. sarcoidosis is seldom associated with crackles and clubbing
Investigations
• CXR/highresolutionCT(seeMedicalImaging,MI6)
■ usually decreased lung volumes
■ reticular, nodular, or reticulonodular pattern (nodular <3 mm) ■ hilar/mediastinal adenopathy (bilateral especially in sarcoidosis)
• PFTs
■ restrictive pattern: decreased lung volumes and compliance
■ normal or increased FEV1/FVC (>70-80%), e.g. flow rates are often normal or high when corrected
for absolute lung volume
■ DLCO decreased due to V/Q mismatch (less surface area for gas exchange ± pulmonary vascular
disease) • ABGs
■ hypoxemia and respiratory alkalosis may be present with progression of disease • other
■ bronchoscopy, bronchoalveolar lavage, lung biopsy
■ ESR, ANA (lupus), RF (RA), serum-precipitating antibodies to inhaled organic antigens
(hypersensitivity pneumonitis), c-ANCA (GPA), anti-GBM (Goodpasture’s)
Unknown Etiologic Agents
IDIOPATHIC PULMONARY FIBROSIS
Definition
• pulmonaryfibrosisofunknowncausewithusualinterstitialpneumonia(UIP)histology(foundon biopsy or inferred from CT)
• a progressive, irreversible condition
• DDx:NSIP,COP,desquamativeinterstitialpneumonitis(DIP),lymphocyticinterstitialpneumonitis
(LIP), Sjögren’s disease
Signs and Symptoms
• commonlypresentsoverage50,incidenceriseswithage;males>females
• dyspneaonexertion,nonproductivecough,constitutionalsymptoms,lateinspiratoryfinecracklesat
lung bases, clubbing
Investigations
• labs(nonspecific,autoimmuneserologyusuallynegative)
• CXR: reticular or reticulonodular pattern with lower lung predominance; often see honeycombing in
advanced disease
• highresolutionCT:lowerzoneperipheralreticularmarkings,tractionbronchiectasis,honeycombing;
ground glass, consolidation, or nodules should not be prominent in IPF
• biopsy: rarely for UIP as honeycombing usually makes diagnosis possible based on radiologic findings
alone
Treatment
• O2
• pirfenidoneandnintedanibcanslowdiseaseprogression • lungtransplantationforadvanceddisease
• meansurvivalof3-5yrafterdiagnosis
SARCOIDOSIS
Definition
• idiopathicnon-infectiousgranulomatousmulti-systemdiseasewithlunginvolvementin90%
• characterizedpathologicallybynon-caseatinggranulomas
• numerousHLAantigenshavebeenshowntoplayaroleandfamilialsarcoidosisisnowrecognized
Epidemiology
• typicallyaffectsyoungandmiddle-agedpatients
• higherincidenceamongpeopleofAfricandescentandfromnorthernlatitudese.g.Scandinavia,
IPF Prevalence
• Age 35-44: 2-7 per 100,000 • Age >75: 175 per 100,000
Effect of Pirfenidone on Mortality: Pooled Analyses and Meta-analyses of Clinical Trials in Idiopathic Pulmonary Fibrosis
Lancet Respir Med 2017;5(1):33-41.
Objectives: To compare mortality outcomes over 120 weeks in patients with idiopathic pulmonary fibrosis on pirfenidone vs. placebo.
Methods: Pooled analysis of 3 global randomized phase III trials (CAPACITY 004 and 006, ASCEND 016, and SP2 and SP3).
Results: All-cause mortality (HR 0.52, 95% CI 0.31-0.87), treatment-emergent all-cause mortality (HR 0.45, 95% CI 0.24-0.83), idiopathic pulmonary fibrosis related mortality (HR 0.35, 95% CI 0.17-0.72), and treatment-emergent idiopathic pulmonary fibrosis (HR 0.32, 95% CI 0.14-0.76) related mortality was reduced in the pirfenidone group vs. placebo.
Conclusions: Pirfenidone therapy is associated with reduction in the relative risk of mortality compared to placebo over 120 wks.
Canada