Idiopathic Pulmonary Fibrosis
Also written as IPF.
*Honeycomb lung with fibroblast foci and a "usual interstitial pneumonia" pattern is the classic diagnostic combination for idiopathic pulmonary fibrosis.*
Treatment at a glance
- An antifibrotic: nintedanib or pirfenidone (slows the decline)
- Oxygen for resting or exertional hypoxaemia, pulmonary rehabilitation, vaccination
Idiopathic pulmonary fibrosis (the commonest idiopathic ILD)
- Who: over 50 years, male , smokers ; chronic, progressive fibrosis with usual interstitial pneumonia (UIP) pattern; unknown cause.
- Clinical: progressive dry cough and exertional breathlessness over months to years; fine "velcro" end-inspiratory crackles at the bases , finger clubbing ; late: cyanosis and cor pulmonale.
- HRCT: subpleural, basal, reticular opacities with honeycombing and traction bronchiectasis (diagnostic without biopsy in the right clinical setting).
- Treatment: antifibrotics (nintedanib, pirfenidone) slow decline; oxygen , pulmonary rehabilitation, treat reflux and cough, vaccinations ; lung transplant in selected patients; palliative care . Steroids do not help (and can harm) in IPF.
- Prognosis: poor; median survival about 3–5 years from diagnosis; acute exacerbations are often fatal.
Read this in Interstitial Lung Diseases
Idiopathic Pulmonary Fibrosis (IPF)
- A pulmonary disorder of unknown etiology characterized by patchy, progressive bilateral interstitial fibrosis.
- Also known as cryptogenic fibrosing alveolitis .
- Affects males more than females and is a disease of aging, rarely occurring before age 50 (and very rarely before 55).
- The histologic and radiologic pattern required for diagnosis is Usual Interstitial Pneumonia (UIP) .
- It is a diagnosis of exclusion , as similar changes can be seen in asbestosis and collagen vascular diseases.
Read this in Lung Pathology — Must-Know
What our notes say
- *Honeycomb lung with fibroblast foci and a "usual interstitial pneumonia" pattern is the classic diagnostic combination for idiopathic pulmonary fibrosis.* (End Sem Cat: Respiratory Pathology: Emphysema, ARDS, Pneumoconiosis)
- Idiopathic Pulmonary Fibrosis (IPF): A chronic, progressive interstitial lung disease of unknown etiology characterized by Usual Interstitial Pneumonia (UIP) pattern. (Lung Pathology — Must-Know)
- Usual Interstitial Pneumonia (UIP): The histologic pattern required for the diagnosis of Idiopathic Pulmonary Fibrosis (IPF), characterized by patchy fibrosis with temporal heterogeneity. (Respiratory System Pathology 1A)
- | Idiopathic interstitial pneumonias | Idiopathic pulmonary fibrosis (IPF), nonspecific interstitial pneumonia (NSIP), cryptogenic organising pneumonia (COP), desquamative interstitial pneumonia | (Interstitial Lung Diseases)
- Idiopathic pulmonary fibrosis (the commonest idiopathic ILD) (Interstitial Lung Diseases)
- I — Infective endocarditis, Idiopathic pulmonary fibrosis (CVS History, Physical Exam & ECG: Master Clinical Assessment)
Study material on Idiopathic Pulmonary Fibrosis
- Respiratory System Pathology 1A
- Interstitial Lung Diseases
- Lung Pathology — Must-Know
- Respiratory Pathology 1b
- Weekly Pathology Exam - October 9, 2026 (Section A: MCQs)
- Weekly Pathology Exam - September 11, 2026 (Section A: MCQs)
- Weekly Pathology Exam - August 28, 2026 (Section A: MCQs)
- Respiratory System Pathology 1A — Practice Questions
- Respiratory System Pathology 1A — Practice Questions
- Respiratory System Pathology 1A — Practice Questions
Practice questions on Idiopathic Pulmonary Fibrosis
A 62-year-old woman with Idiopathic Pulmonary Fibrosis (IPF) has worsening dyspnea over 2 weeks without infection. HRCT now shows new bilateral ground-glass opacities superimposed on her existing fibrosis. What is the most likely complication?
- Acute exacerbation of IPF
- Pneumonia
- Pulmonary embolism
- Pleural effusion
Answer: A. New ground-glass opacities in a patient with known IPF, especially with acute worsening dyspnea, are highly suggestive of an acute exacerbation of IPF.
Pulmonary function testing in a patient with Idiopathic Pulmonary Fibrosis (IPF) is most likely to show which pattern?
- Obstructive pattern with normal DLCO
- Restrictive pattern with decreased DLCO
- Obstructive pattern with decreased DLCO
- Restrictive pattern with normal DLCO
Answer: B. IPF is a restrictive lung disease characterized by reduced lung volumes and a reduced diffusing capacity for carbon monoxide (DLCO) due to thickened alveolar walls.
A 62-year-old woman with Idiopathic Pulmonary Fibrosis (IPF) has worsening dyspnea over 2 weeks without infection. HRCT now shows new bilateral ground-glass opacities superimposed on her existing fibrosis. What is the most likely complication?
- Pulmonary embolism
- Acute exacerbation of IPF
- Pneumothorax
- Bacterial pneumonia
Answer: B. New ground-glass opacities in a patient with IPF, especially with worsening dyspnea and no clear infectious cause, are highly suggestive of an acute exacerbation of IPF. Pulmonary embolism can occur but is less likely to present with diffuse ground-glass opacities. Pneumothorax and bacterial pneumonia would typically have different HRCT findings or clinical clues.
Pulmonary function testing in a patient with Idiopathic Pulmonary Fibrosis (IPF) is most likely to show which pattern?
- Obstructive pattern with decreased FEV1/FVC ratio
- Restrictive pattern with decreased TLC, FVC, and normal or increased FEV1/FVC ratio
- Normal lung volumes with decreased diffusion capacity
- Obstructive pattern with increased lung volumes
Answer: B. IPF is a fibrotic interstitial lung disease, characterized by a restrictive pattern on pulmonary function tests. This means lung volumes (Total Lung Capacity - TLC, Forced Vital Capacity - FVC) are reduced, while the ratio of Forced Expiratory Volume in 1 second (FEV1) to FVC is typically normal or even increased.
A 62-year-old woman with Idiopathic Pulmonary Fibrosis (IPF) has worsening dyspnea over 2 weeks without infection. HRCT now shows new bilateral ground-glass opacities superimposed on her existing fibrosis. Most likely complication?
- Pulmonary embolism
- Acute exacerbation of IPF
- Pneumonia
- Malignancy
Answer: B. New ground-glass opacities in a patient with IPF, especially with worsening dyspnea without clear signs of infection, are highly suggestive of an acute exacerbation of IPF. Pulmonary embolism, pneumonia, and malignancy are less likely given the presentation.
Pulmonary function testing in a patient with Idiopathic Pulmonary Fibrosis (IPF) is most likely to show which pattern?
- Obstructive pattern with increased FEV1/FVC ratio
- Restrictive pattern with decreased FEV1, FVC, and TLC
- Obstructive pattern with decreased FEV1/FVC ratio
- Normal spirometry
Answer: B. IPF is a restrictive lung disease, characterized by reduced lung volumes, including FEV1 (Forced Expiratory Volume in 1 second), FVC (Forced Vital Capacity), and TLC (Total Lung Capacity), leading to a restrictive pattern on PFTs. The FEV1/FVC ratio is typically normal or increased.