Pulmonary · Topic 12 of 28

Interstitial Lung Disease

Pulmonary · interstitial lung disease

Interstitial Lung Disease

IPF is a UIP pattern on HRCT with no other cause: slow it with an antifibrotic, never with steroids — except in an acute exacerbation.

Key numbers

Acute exacerbation: new bilateral ground-glass< 1 month

Progressive fibrosis: 2 of 3 in 1 yearFVC ↓ ≥ 5% in 1 yr

01 · Defined byHRCT UIP pattern diagnoses IPF

IPF = a usual interstitial pneumonia (UIP) pattern on HRCT — subpleural, basal reticulation with honeycombing and traction bronchiectasis — with exposures, drugs and connective tissue disease excluded; biopsy is usually unnecessary.

02 · GiveAntifibrotic: nintedanib or pirfenidone

Slow IPF with an antifibrotic — nintedanib 150 mg twice daily or pirfenidone 801 mg three times daily with food; neither is clearly better, and both need liver tests before and during therapy.

03 · Defined byAcute exacerbation: new bilateral ground-glass

Acute exacerbation of IPF = dyspnea worsening over less than 1 month with new bilateral ground-glass opacity or consolidation on a UIP background, not fully explained by heart failure or fluid overload.

Causes & risk factors

Why it happens

Search for exposures, drugs and CTDBefore calling ILD idiopathic, take an occupational and environmental exposure history, review drugs (amiodarone, nitrofurantoin, methotrexate, bleomycin, checkpoint inhibitors) and check serologies for connective tissue disease.

Presentation

What you'll see

Bibasilar Velcro crackles and clubbingIPF presents in adults over 50 (men 2:1, often smokers) with months of exertional dyspnea, dry cough and fine bibasilar 'Velcro' crackles; clubbing occurs in about half.

Diagnosis & monitoring

Work-up

Restrictive PFTs with a low DLCOPFTs show restriction (normal-to-low FVC) and a reduced DLCO in nearly every patient, with exertional desaturation that progresses to resting hypoxemia.

Progressive fibrosis: 2 of 3 in 1 yearProgressive pulmonary fibrosis (non-IPF) = 2 of 3 within a year: worse symptoms, radiologic progression, or absolute FVC fall ≥ 5% or DLCO fall ≥ 10% predicted. Nintedanib is suggested if standard management fails.

Nintedanib causes diarrhea; pirfenidone causes photosensitivityNintedanib: diarrhea (treat early with loperamide), liver injury, bleeding risk, avoid in pregnancy and moderate–severe hepatic impairment. Pirfenidone: nausea, rash and photosensitivity — sunscreen and sun avoidance.

Median survival in IPF: 3–5 yearsIPF is relentlessly progressive: median survival is about 3–5 years from diagnosis, so advance care planning belongs in early visits.

Do right now

In this order

First moves

Rule out infection, PE, pneumothorax, heart failure

→

Acute exacerbation: steroids plus empiric antibiotics

→

Most AE-IPF patients should not be intubated

Why each step

Rule out infection, PE, pneumothorax, heart failureAcute worsening in IPF is often a treatable complication — infection, pulmonary embolism, pneumothorax or heart failure; exclude these with CT, echo and cultures before labeling it an acute exacerbation.

Acute exacerbation: steroids plus empiric antibioticsTreat an acute exacerbation of IPF with high-dose corticosteroids (weak recommendation) and empiric antibiotics while infection is being excluded; support oxygenation (high-flow nasal cannula or NIV).

Most AE-IPF patients should not be intubatedMechanical ventilation is not recommended for most patients with respiratory failure from IPF — in-hospital mortality is about 67% when ventilated; discuss goals early and reserve it for a bridge to transplant.

Management

Orders

Refer for lung transplant at diagnosisAdd supplemental oxygen and pulmonary rehabilitation, refer suitable patients for lung transplantation at diagnosis, and involve palliative care early for dyspnea and cough.

Red flags & don'ts

Avoid harm

No maintenance steroids for stable IPF avoidGlucocorticoids are not recommended for stable IPF; they are reserved for steroid-responsive ILDs such as cryptogenic organizing pneumonia, nonspecific interstitial pneumonia and lymphoid interstitial pneumonia.

More detail

Reference

Show 5 reference facts

IPF raises the risk of pulmonary hypertension and lung cancer; inhaled treprostinil helps PH due to ILD, while endothelin antagonists and riociguat are avoided there.

The 2022 ATS/ERS/JRS/ALAT guideline advises against antacid therapy and antireflux surgery to improve respiratory outcomes in IPF.

When tissue is needed, transbronchial lung cryobiopsy is an acceptable alternative to surgical lung biopsy in experienced centers; the diagnosis is made at a multidisciplinary discussion.

Nerandomilast (oral PDE4 inhibitor, 18 mg twice daily) was FDA-approved for IPF in October 2025 and for progressive pulmonary fibrosis in December 2025; it slows FVC decline.

Up to 46% of IPF deaths are preceded by an acute exacerbation; most patients who die do so within the first month of the exacerbation.

Pearl

Velcro crackles at both bases in an older smoker with exertional dyspnea: get an HRCT, not another course of prednisone.

Sources · Merck Manual Professional — Idiopathic Pulmonary Fibrosis (IPF) · Raghu G et al. Idiopathic Pulmonary Fibrosis (an Update) and Progressive Pulmonary Fibrosis in Adults: ATS/ERS/JRS/ALAT Guideline. Am J Respir Crit Care Med 2022;205:e18–e47 · OFEV (nintedanib) prescribing information — DailyMed · ESBRIET (pirfenidone) prescribing information — DailyMed · Merck Manual Professional — Overview of Idiopathic Interstitial Pneumonias · Kondoh Y, Cottin V, Brown KK. Recent lessons learned in the management of acute exacerbation of IPF. Eur Respir Rev 2017 · Merck Manual Professional — Overview of Interstitial Lung Disease · Merck Manual Professional — Pulmonary Hypertension · HealthDay — FDA approves Jascayd (nerandomilast) for idiopathic pulmonary fibrosis (Oct 2025) · HealthDay — FDA approves Jascayd for progressive pulmonary fibrosis (Dec 2025) · JASCAYD (nerandomilast) prescribing information — DailyMed · Starter sheet built from the verified AGACNP fact map (facts reviewed 2026-10-15).