Makindo Medical Notes

Fibrotic interstitial lung diseases (ILDs) are disorders with irreversible scarring of the lung interstitium → reduced compliance, impaired gas exchange, and progressive breathlessness. The archetype is Idiopathic Pulmonary Fibrosis (IPF) with a usual interstitial pneumonia (UIP) pattern. 🫁

🧭 Classification

• 🧩 Idiopathic: IPF (UIP), idiopathic NSIP.
• 🧪 Autoimmune/CTD-ILD: RA-ILD, SSc-ILD, myositis-ILD, MCTD.
• 🌿 Exposure-related: Chronic hypersensitivity pneumonitis (birds/moulds), occupational (silica, asbestos).
• 💊 Drug/radiation: Amiodarone, bleomycin, methotrexate, nitrofurantoin; thoracic RT.
• 👨‍👩‍👧 Genetic/familial: MUC5B, TERT/TERC, surfactant protein variants.

🧬 Pathophysiology (Why lungs scar?)

• 🔁 Repeated alveolar epithelial injury (ageing, reflux microaspiration, smoke, antigens) → abnormal wound repair.
• 🧵 Fibroblast foci lay down collagen + extracellular matrix → architectural distortion, honeycombing.
• 📡 Pro-fibrotic signalling: TGF-β, CTGF, imbalance of MMP/TIMP; failed apoptosis of myofibroblasts.
• 🧬 Susceptibility: MUC5B promoter, short telomeres (TERT/TERC) → earlier onset/faster decline.

🩺 Clinical Features

• 😮‍💨 Progressive exertional dyspnoea (months–years), dry cough.
• 🎧 Fine “Velcro” inspiratory crackles (bibasal), 👆 digital clubbing (±).
• ❤️ Late: pulmonary hypertension signs (loud P2, oedema, syncope).
• 🧑‍⚕️ Clues to cause: arthralgia/Raynaud’s (CTD-ILD), bird exposure (HP), drug history.

🧪 Investigations (UK approach)

• 📟 PFTs: Restriction (↓FVC, ↓TLC), ↓DLCO; 6-min walk with desaturation.
• 🩻 HRCT (key):
  • UIP: subpleural/basal reticulation, traction bronchiectasis, honeycombing 🧇, heterogeneity.
  • NSIP: basal ground-glass + fine reticulation, little/no honeycombing, relative homogeneity.
  • HP (chronic): upper-mid predominance, mosaic attenuation/air-trapping, centrilobular nodules.
• 🧫 Bloods: FBC, U&E, LFT; autoimmune panel (ANA, ENA, RF/anti-CCP, myositis antibodies).
• 🕊️ Exposure work-up: Detailed occupational/hobby history; serum precipitins (HP) where appropriate.
• 🧵 Tissue (selective): Cryobiopsy/VATS if HRCT non-diagnostic and result will change management.
• 👥 MDT discussion (radiology + respiratory + pathology) = gold standard for diagnosis.

📊 Quick Pattern Table

Pattern 🖼️	Likely Dx	Clues	Management headline
UIP (honeycombing, basal/subpleural)	IPF, RA-ILD	Age >60, male, smoker	🎯 Antifibrotics (pirfenidone/nintedanib)
NSIP (GGOs + fine reticulation)	CTD-ILD, idiopathic NSIP	Autoimmune features	🛡️ Immunomodulation ± antifibrotic if progressive
Mosaic + air-trapping, mid-upper	Chronic HP	Bird/mould exposure	🚫 Antigen avoidance + therapy

💊 Management (stepwise)

• 🌱 General: Stop smoking 🚭, vaccinate 💉 (influenza, pneumococcus, COVID), pulmonary rehab 🏃, optimise reflux/OSA.
• 🫁 Antifibrotics (IPF & progressive fibrosing ILD):
  • Pirfenidone – slows FVC decline; SE: nausea, photosensitivity 🌞, LFT ↑.
  • Nintedanib – tyrosine kinase inhibitor; SE: diarrhoea 💩, LFT ↑, bleeding risk.
• 🛡️ Immunomodulation (non-IPF where inflammatory component): e.g., mycophenolate, azathioprine; consider steroids in CTD-ILD/HP flares (avoid in stable IPF).
• 💨 Oxygen: if resting or exertional hypoxaemia (improves symptoms/exercise capacity).
• 🧾 Comorbidities: PH management, reflux treatment, mood/sleep support.
• 🔁 Monitoring: FVC/DLCO each 3–6 months; 6MWT; HRCT if clinical change. Progression = ≥10% FVC fall or symptomatic/radiologic worsening.
• 🫀 Transplant referral: early for eligible patients (age/fitness criteria). 🌱
• 🤝 Palliative care: breathlessness, cough, anxiety; advance care planning.

🚑 Acute Exacerbation (AE-ILD)

• 📈 Acute (≤1 month) worsening dyspnoea + new bilateral GGOs on HRCT, not explained by heart failure/PE.
• 🏥 Manage as emergency: exclude infection/PE, high-flow O₂, cautious diuresis if needed, consider steroid trial (evidence limited), treat triggers, discuss ceilings of care.

🧠 Case Vignettes

• Case 1 (IPF classic) 👴: 72-year-old ex-smoker with 12-month dyspnoea, “Velcro” crackles; HRCT shows basal honeycombing. → Start antifibrotic, vaccinate, rehab, early transplant discussion if suitable.
• Case 2 (CTD-ILD) 🧤: 55-year-old woman with Raynaud’s and arthralgia; HRCT NSIP. → Rheumatology collab, mycophenolate ± steroid taper, screen for pulmonary hypertension.
• Case 3 (HP) 🕊️: 48-year-old bird breeder with cough, mosaic attenuation + air-trapping. → Antigen avoidance, consider steroids; monitor for fibrotic progression → nintedanib if progressive.
• Case 4 (AE-IPF) 🚨: 68-year-old with IPF, acute hypoxaemia and new GGOs. → Admit, broad infection screen, high-flow O₂, MDT, steroid trial after excluding infection.

🧷 Practical OSCE/Exam Pearls

• 🎧 “Velcro” crackles + clubbing → think ILD; ask smoking, reflux, birds/moulds, occupational history.
• 🖼️ HRCT pattern drives management: UIP → antifibrotic; NSIP/HP → consider immunomodulation.
• 💊 Avoid routine steroids in stable IPF (harm shown with triple therapy in past trials).
• 📉 Clinically meaningful decline: ≥10% FVC fall or symptomatic/radiologic progression.
• 🧳 Early referral to ILD centre + transplant assessment for eligible patients.

📏 Prognosis

• ⏳ IPF median survival ~3–5 years from diagnosis (variable); worse with older age, low baseline FVC/DLCO, pulmonary hypertension, frequent exacerbations.
• 📉 Antifibrotics slow decline but do not reverse fibrosis.

🔗 UK Context / Safety

• 🇬🇧 MDT ILD clinic standard; follow local pathways for antifibrotic eligibility and monitoring (LFTs, side effects).
• 💉 Vaccinations (influenza, pneumococcal, COVID) and smoking cessation are high-value interventions.
• 🧼 HP: emphasise antigen avoidance (home/work remediation) to change disease course.

🗂️ Antifibrotic Quick Reference

Drug	Use	Benefits	Key AEs ⚠️	Monitoring
Pirfenidone	IPF; some progressive fibrosing ILD	↓ FVC decline	Nausea, photosensitivity, LFT ↑	LFTs; sun protection
Nintedanib	IPF & progressive fibrosing ILD	↓ FVC decline	Diarrhoea, LFT ↑, bleeding risk	LFTs; manage GI side effects

🧭 Follow-up Plan (template)

• 📆 Review 3–6-monthly: symptoms, PFTs (FVC, DLCO), 6MWT ± oximetry.
• 🩻 HRCT if clinical change/exacerbation or annually if indicated.
• 💬 Discuss goals of care early; consider palliative input for symptom control.

🌬️ Case 1 — Idiopathic Pulmonary Fibrosis (IPF)

A 72-year-old man presents with progressive exertional breathlessness and a persistent dry cough. Examination reveals fine "Velcro" crackles at the lung bases and digital clubbing. 💡 IPF is the most common idiopathic interstitial pneumonia, characterised by progressive scarring of the lung parenchyma. HRCT typically shows a usual interstitial pneumonia (UIP) pattern. Management includes antifibrotic agents (nintedanib, pirfenidone), pulmonary rehabilitation, and consideration of lung transplantation in selected patients.

🌬️ Case 2 — Fibrosis Secondary to Rheumatoid Arthritis

A 64-year-old woman with longstanding rheumatoid arthritis reports worsening breathlessness and cough. Examination reveals basal crackles and her chest X-ray shows bilateral interstitial changes. 💡 Autoimmune conditions such as rheumatoid arthritis can cause interstitial lung disease through chronic inflammation. Methotrexate and other DMARDs may also contribute. Management involves optimising rheumatoid control, stopping offending drugs, and referral to an ILD specialist team.

🌬️ Case 3 — Occupational Lung Fibrosis (Asbestosis)

A 70-year-old retired shipyard worker presents with gradually worsening breathlessness and reduced exercise tolerance. He has basal end-inspiratory crackles and clubbing. 💡 Asbestosis is a pneumoconiosis caused by prolonged asbestos exposure, with a latency of decades. It leads to diffuse pulmonary fibrosis and increases the risk of mesothelioma and lung cancer. Management is supportive, focusing on smoking cessation, oxygen if required, and regular surveillance for malignancy.

🌬️ Case 4 — Drug-Induced Pulmonary Fibrosis

A 58-year-old man on long-term amiodarone for atrial fibrillation presents with progressive dyspnoea and dry cough. HRCT shows diffuse interstitial changes. 💡 Several drugs, including amiodarone, bleomycin, and methotrexate, can cause fibrotic lung disease through direct pulmonary toxicity. Management involves withdrawing the offending drug, supportive care, and occasionally corticosteroids if inflammation is active.

🌬️ Case 5 — Sarcoidosis with Pulmonary Fibrosis

A 45-year-old Afro-Caribbean woman presents with chronic cough, dyspnoea, and fatigue. Chest imaging shows upper-zone fibrosis with hilar lymphadenopathy. 💡 Sarcoidosis is a multisystem granulomatous disease that can progress to pulmonary fibrosis in advanced stages. Fibrosis is more common in chronic disease, particularly in Black patients. Management depends on severity; corticosteroids or immunosuppressants are used if there is progressive respiratory compromise.