🔍 Question

A 42-year-old woman presents with a dry cough and worsening shortness of breath during physical activity. Her medical history includes primary pulmonary hypertension, and she underwent a lung transplant 8 months ago. She reports taking all prescribed transplant medications without any missed doses. A chest X-ray shows postoperative changes consistent with her transplant, but the lung fields are clear. Pulmonary function tests reveal a forced expiratory volume in 1 second (FEV1) at 67% of her best post-transplant value, with her forced vital capacity remaining stable. A lung biopsy shows significant fibrotic obstruction in the terminal bronchioles.

What is the most likely cause of her symptoms?

• A. Acute rejection

• B. Chronic obstructive pulmonary disease

• C. Chronic Transplant rejection

• D. Ischemia-reperfusion injury

• E. Opportunistic infection

• F. Recurrence of pulmonary hypertension

Correct Answer: C. Chronic Transplant Rejection

Chronic transplant rejection = Obliterative Bronchiolitis 🧠

1. Biopsy Clue → Fibrosis = Chronic Process

2. Timeline Clue → 8 Months = Late Post-Transplant Issue

3. Physiology Clue → FEV1 ↓ + Normal FVC = Obstructive Pattern

⚙️

Lung Transplantation

⬇

Immune Response to Allograft

• Chronic low-grade T-cell mediated injury

• Cytokine production ↑ → Activation of fibroblasts 🧠

⬇

 Bronchiolar Injury

• Damage to epithelial cells of terminal bronchioles

⬇

Fibrotic Repair

• Excess collagen deposition

• Fibrotic obliteration of small airways 🧠 (Obliterative Bronchiolitis)

⬇

↓ Airflow (Obstructive Pattern)

• FEV1 ↓

• FVC remains unchanged

⬇

Chronic Transplant Rejection Diagnosis

• Hallmark: Fibrotic obstruction of bronchioles on biopsy

Imagine bronchioles as tiny tubes in a pipe system.

• Normal → Air flows freely 🧩

• Fibrotic Injury → The tubes become narrowed & blocked ⚙

• This reduces airflow (↓ FEV1) while total volume (FVC) remains stable.

How to Approach This Question? 🔍

Symptom Onset & Duration ⚙

Chronic timeline (8 months post-transplant) 🧠

⬇

Functional Changes 🧠

• ↓ FEV1 + Normal FVC → Obstructive pattern

• 🧩 Clue: Unchanged lung fields = Nonparenchymal issue

⬇

Biopsy Findings ⚙

• Fibrotic obstruction = Obliterative Bronchiolitis 🧠

⬇

Conclusion 🔍

• Diagnosis: Chronic Transplant Rejection

• Mechanism: Chronic low-grade immune-mediated injury → Fibrosis of small airways

⚖️ Explanation of Other Differentials

📝 Flashcards

Stay Hungry, Stay Curious!

Your Brother In This Struggle

Dr. Shoaib Ahmad

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