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Interstitial Lung Disease — Diagnosis & Management

Registrar quick reference · ATS/ERS/JRS/ALAT 2022 (IPF + PPF)
Compiled Jun 2026
Verify doses & PBS
MDD diagnosis · hunt the cause
Decision support only — not a substitute for the ATS/ERS/JRS/ALAT guidelines, eTG, or your ILD/MDD team. The pivotal split is IPF vs non-IPF: it determines whether you reach for an antifibrotic or immunosuppression — and getting it wrong can harm. Diagnosis is by multidisciplinary discussion (radiology + pathology + clinical). Verify all doses.
1 The treatment divergence — get the bucket right
IPFUIP, cause excluded
UIP / probable UIP on HRCT + no identifiable cause, confirmed at MDD.
Antifibrotic (nintedanib or pirfenidone). Do NOT immunosuppress — triple therapy increased death/hospitalisation PANTHER-IPF.
Inflammatory non-IPFoften treatable
CTD-ILD, hypersensitivity pneumonitis, NSIP, organising pneumonia, sarcoidosis.
Treat the cause + immunosuppress (corticosteroid ± MMF/azathioprine/rituximab). Antigen avoidance for HP.
Progressive pulmonary fibrosisnon-IPF that progresses
Non-IPF fibrotic ILD + ≥2 of: worsening symptoms, FVC ↓≥5%, DLCO ↓≥10%, or radiological progression — within 1 year.
Add nintedanib on top of standard management INBUILD. The newer, easily-missed bucket.
Everyoneregardless of subtype
All ILD.
Pulmonary rehab, oxygen, vaccinate, treat comorbidities, early transplant referral, palliative/cough care.
MDD + HRCT pattern + a cause-hunt assign the bucket — don't label the subtype in isolation. Antifibrotics slow FVC decline (~50%); they don't reverse fibrosis. IPF median survival is ~5–7 years even on treatment, so transplant referral should be early.
2 Diagnose — hunt the cause, then take it to MDD

History & exam

  • ExposuresBirds, mould, hot tubs, occupational (HP, pneumoconiosis); asbestos, silica.
  • DrugsAmiodarone, methotrexate, nitrofurantoin, chemo, immunotherapy.
  • CTDRaynaud, arthralgia, rash, sicca, dysphagia, mechanic's hands. Velcro crackles + clubbing → think UIP/IPF.

Tests

  • SerologyANA, ENA, RF, anti-CCP, myositis panel (anti-Jo1/MDA5), ANCA; precipitins for HP.
  • PFTsRestrictive (↓FVC, ↓TLC, ↓DLCO); FVC tracks progression; 6MWT for desaturation.
  • BAL/biopsyBAL lymphocytosis → HP/sarcoid/NSIP. Cryobiopsy or surgical biopsy if MDD can't resolve.

MDD is the gold standard

  • WhoRadiologist + pulmonologist + pathologist (± rheumatologist) together.
  • Biopsy?UIP / probable UIP on HRCT + no cause → IPF without biopsy after MDD.
  • Don'tDon't assign a subtype solo — discordance between radiology, path and clinic is common.
3 Read the HRCT pattern

UIP & its mimics

  • UIPSubpleural + basal predominant, reticulation, honeycombing, traction bronchiectasis → IPF if no cause.
  • ProbableSubpleural/basal reticulation + traction bronchiectasis, no honeycombing.
  • IndeterminateDoesn't fit — needs biopsy/MDD.

Alternative patterns

  • NSIPGround-glass, subpleural sparing, less honeycombing — think CTD.
  • HPMosaic attenuation/air-trapping, centrilobular nodules, three-density sign.
  • OPPeripheral/peribronchial migratory consolidation — steroid-responsive.
4 Treat by bucket

IPF

  • AntifibroticNintedanib (diarrhoea, ↑LFTs) or pirfenidone (photosensitivity, GI, ↑LFTs) — slow FVC decline INPULSIS · ASCEND · CAPACITY.
  • Don'tNo prednisone/azathioprine/NAC — harm PANTHER-IPF. Also: 2022 guideline suggests against antacids for respiratory outcomes.
  • TransplantRefer early — course is unpredictable.

Non-IPF & PPF

  • InflammatoryCorticosteroid ± MMF / azathioprine / rituximab; treat the underlying CTD.
  • SSc-ILDNintedanib SENSCIS ± MMF ± tocilizumab.
  • HPAntigen avoidance is central; steroids for inflammatory disease.
  • PPFProgressing despite standard care → add nintedanib INBUILD.
5 Monitor, prognosticate & the traps

Follow & prognosticate

  • TrackSerial FVC & DLCO, symptoms, HRCT; FVC decline is the key prognostic signal.
  • GAPGAP index (gender, age, FVC, DLCO) for IPF prognosis.
  • AE-ILDAcute exacerbation = high mortality; exclude infection/PE/HF before assuming progression.

The traps

  • Wrong bucketImmunosuppressing IPF harms; missing a treatable CTD/HP/drug cause wastes a reversible opportunity.
  • Miss PPFNon-IPF ILD can progress like IPF — reassess for the PPF criteria, don't just watch.
  • Set expectationsAntifibrotics slow, don't cure — frame this honestly and involve palliative care early.
Sources. Raghu et al. "Idiopathic Pulmonary Fibrosis (an Update) and Progressive Pulmonary Fibrosis in Adults: An Official ATS/ERS/JRS/ALAT Clinical Practice Guideline," Am J Respir Crit Care Med 2022 (UIP HRCT patterns, MDD, antifibrotics, PPF definition + nintedanib, against antacids). ATS/ERS 2020 hypersensitivity pneumonitis guideline; ATS/ERS 2013 IIP classification. TSANZ / Australian IPF Registry; eTG; PBS for antifibrotics.   Key trials: INPULSIS (nintedanib IPF), ASCEND/CAPACITY (pirfenidone IPF), INBUILD (nintedanib in PPF), SENSCIS (nintedanib SSc-ILD), PANTHER-IPF (immunosuppression harm in IPF); GAP index (prognosis).   Caveats: PPF is defined within the last year and requires excluding alternative explanations. Antifibrotic access is PBS-restricted in Australia — confirm criteria. The IPF/non-IPF distinction can be genuinely difficult; default to MDD. Verify all doses and monitoring. Companion to the respiratory set.