Restrictive Lung Diseases

Idiopathic Pulmonary Fibrosis (IPF)

🔹 Definition

• Progressive interstitial fibrosis of unknown cause

🔹 Key Word

• UIP (Usual Interstitial Pneumonia)

🔹 Pathogenesis

• Repeated alveolar injury + defective repair

🔹 Morphology

• Patchy fibrosis

• Fibroblastic foci

• Honeycomb lung (end stage)

🔹 Clinical

• Dry cough + progressive dyspnea

• Poor prognosis (3–5 years)

🎯 Exam Traps

• Diagnosis of exclusion

• Affects older males

• Lower lobes + subpleural

NSIP (Nonspecific Interstitial Pneumonia)

🔹 Key Idea

• More uniform fibrosis

🔹 Association

• Collagen vascular diseases (RA)

🔹 Morphology

• Mild–moderate inflammation/fibrosis

• Uniform appearance

🔹 Clinical

• Better prognosis than IPF

🎯 Exam Trap

• If question says uniform → NSIP (NOT IPF)

COP (Cryptogenic Organizing Pneumonia)

🔹 Key Feature

• Intraalveolar plugs

🔹 Symptoms

• Cough + dyspnea

🔹 Imaging

• Patchy consolidation

🔹 Treatment

• Steroids

🎯 Exam Trap

• “Organizing connective tissue in alveoli” → COP

Pneumoconiosis (Dust Diseases)

General Pneumoconiosis

🔹 Cause

• Inhalation of dust (silica, asbestos, coal)

🔹 Mechanism

1. Macrophage ingestion

2. IL-1 release

3. Inflammation → fibrosis

🔹 Important Factor

• Particle size: 1–5 µm (most dangerous)

🎯 Exam Trap

• Macrophage = key cell

Coal Worker’s Pneumoconiosis (CWP)⭐️

🔹 Types

• Anthracosis → benign

• Simple → mild

• Complicated (PMF) → severe fibrosis

🔹 Morphology

• Coal macules + nodules

🎯 Exam Trap

• Progressive massive fibrosis (PMF) = severe stage

Silicosis⭐️

🔹 Cause

• Inhalation of silica

🔹 Pathogenesis

• Macrophage activation → inflammation

🔹 Morphology

• Concentric collagen nodules

🔹 Clinical

• Late dyspnea

🎯 VERY IMPORTANT

• ↑ Risk of TB

• ↑ Risk of lung cancer

Asbestosis⭐️

🔹 Cause

• Asbestos exposure

🔹 Morphology

• Asbestos bodies (golden-brown rods)

• Lower lobes + subpleural fibrosis

🔹 Complications

• Lung carcinoma

• Mesothelioma

🎯 Exam Traps

• Smoking ↑ lung cancer (NOT mesothelioma)

• Pleural plaques

Sarcoidosis(Granulmatous)

🔹 Key Feature

• Non-caseating granuloma

🔹 Pathogenesis

• Immune dysregulation

🔹 Morphology

• Schaumann bodies

• Asteroid bodies

🔹 Prognosis

• Many recover

🎯 Exam Trap

• Non-caseating = NOT TB

Hypersensitivity Pneumonitis

🔹 Cause

• Allergic reaction to inhaled antigen

🔹 Key Feature

• Affects alveoli

🔹 Morphology

• Poorly formed granulomas

• Peribronchiolar

🔹 Outcome

• Chronic exposure → fibrosis

🎯 Exam Trap

• “Allergic alveolitis” = same disease

🚬 Smoking-Related Diseases

Desquamative Interstitial Pneumonia (DIP)

🔹 Key Feature

• Macrophages in alveoli

🔹 Morphology

• Mild fibrosis

🔹 Prognosis

• Good

🔹 Treatment

• Smoking cessation + steroids

🎯 Exam Trap

• “Smoker + macrophages in airspaces” → DIP

🟪 Respiratory Bronchiolitis

🔹 Key Feature

• Macrophages in bronchioles

🔹 Distribution

• Bronchiolocentric

🔹 Symptoms

• Mild dyspnea + cough

🎯 Exam Trap

• Bronchioles (NOT alveoli like DIP)

🔥 FINAL RAPID REVISION (1 minute before exam)

• IPF → UIP + honeycomb + bad prognosis

• NSIP → uniform + better

• COP → plugs + steroids

• Pneumoconiosis → dust + macrophage + IL-1

• Silicosis → ↑ TB

• Asbestos → mesothelioma

• Sarcoidosis → non-caseating granuloma

• Hypersensitivity → allergic

• DIP → alveoli macrophages

• Bronchiolitis → bronchioles macrophages