Interstitial Lung Disease

Patient: 72M with progressive dyspnea × 2 years and dry cough. Bibasilar velcro crackles. PFTs: FVC 58%, DLCO 42% (restrictive + impaired gas exchange). HRCT: basal-predominant honeycombing, traction bronchiectasis, minimal GGO. UIP pattern.

Key findings: Definite UIP pattern on HRCT = IPF diagnosis without biopsy needed (if clinical context fits). IPF is the most common and most lethal ILD, median survival 3-5 years from diagnosis.

Management:

• Antifibrotic therapy: pirfenidone or nintedanib (slows FVC decline by ~50%) ASCEND/INPULSIS, 2014
• Pulmonary rehabilitation (improves exercise capacity and QOL even as disease progresses)
• Supplemental O₂ for resting SpO₂ < 88% or exertional desaturation
• Lung transplant evaluation if age < 70, no major comorbidities, refer EARLY (waitlist mortality is high)
• NO steroids or immunosuppression (PANTHER-IPF showed HARM from prednisone + azathioprine + NAC in IPF)

Teaching point: Steroids are HARMFUL in IPF, this is the one ILD where immunosuppression makes things worse. Antifibrotics (pirfenidone, nintedanib) slow progression but do not reverse fibrosis. Early transplant referral is critical.

Patient: 55F bird breeder with progressive dyspnea × 1 year. HRCT: diffuse GGO with mosaic attenuation, air trapping on expiratory images, centrilobular nodules. No honeycombing. PFTs: FVC 68%, DLCO 52%. BAL: lymphocytosis 48%.

Key findings: Chronic hypersensitivity pneumonitis from avian antigen exposure. HRCT pattern: GGO + mosaic attenuation + air trapping is classic. BAL lymphocytosis (> 30%) supports the diagnosis. Unlike IPF, HP is potentially reversible with antigen avoidance.

Management:

• Antigen avoidance is the MOST important intervention, remove birds, professional home cleaning
• Prednisone 0.5 mg/kg daily × 4-8 weeks for symptomatic disease, then slow taper
• If fibrotic HP refractory to steroids: mycophenolate or azathioprine as steroid-sparing agents
• If fibrotic HP progressing despite antigen avoidance + immunosuppression: consider antifibrotic (nintedanib approved for progressive fibrosing ILD)
• Serial PFTs q3-6 months to monitor for progression vs stabilization

Teaching point: HP is the treatable mimic of IPF. The key differentiators: HP has GGO + mosaic attenuation (not honeycombing), BAL lymphocytosis, and an identifiable exposure. Antigen removal can halt or reverse disease if caught before fibrosis.

Patient: 68M with known IPF on nintedanib. Admitted with acute worsening dyspnea × 5 days. SpO₂ 78% on 6L NC. CT: new bilateral GGO superimposed on known UIP pattern. No PE on CTA. Sputum cultures negative.

Key findings: Acute exacerbation of IPF: rapid respiratory deterioration + new bilateral GGO on CT + no identifiable cause (ruled out infection, PE, HF). Mortality > 50% per episode.

Management:

• High-dose methylprednisolone 1g IV daily × 3 days → prednisone 1 mg/kg taper (limited evidence but standard practice)
• Broad-spectrum antibiotics until infection excluded (empiric coverage while cultures pending)
• High-flow nasal cannula or NIV for respiratory support, intubation carries very poor prognosis in IPF
• Discuss goals of care early, in-hospital mortality for intubated IPF patients exceeds 80%
• Continue antifibrotic therapy if able to take PO

Teaching point: Acute exacerbation of IPF is often fatal. The most important conversation is goals of care, mechanical ventilation in IPF rarely leads to meaningful recovery. Palliative care should be involved early if the patient does not respond to steroids within 48-72h.