20th February 2025

Idiopathic pulmonary fibrosis (IPF)

Overview of IPF

Idiopathic pulmonary fibrosis is the most prevalent IIP. The pathogenesis is poorly understood, but the characteristic histological pattern is usual interstitial pneumonia (UIP). It is more common in older men.

Signs and symptoms include:

• Progressive exertional dyspnoea
• Cough (typically dry)
• Bi-basal, fine, end-inspiratory crackles which do not clear on coughing
• Clubbing

Diagnosis of IPF

Key investigations include:

• Blood tests (mostly to exclude alternative diagnoses): ANA, RF (rheumatoid factor), anti-centromere, anti-Ro, anti-La, anti-RNP, anti-dsDNA, anti-smith, anti tRNA synthetase, anti-PM-Scl, anti-Th/To, anti-U3 RNP, ANCA panel, anti-topoisomerase (Scl-70)
• Lung function tests: classically show a restrictive pattern and reduced transfer factor (TLCO). Should be performed at the time of diagnosis, 6 and 12 months
• Chest X-ray: bilateral, peripheral and basal interstitial reticulation. Sometimes, honeycombing is visible
• High-resolution CT (HRCT) thorax: the investigation of choice. Features include bilateral, subpleural, predominantly basal reticulation and honeycombing (must be present for a definite radiological diagnosis of UIP)
• Histology: UIP – alternating areas of normal lung, interstitial inflammation, fibroblast foci and honeycombing

NICE recommends that a bronchoalveolar lavage, transbronchial biopsy or surgical lung biopsy should be considered if the multidisciplinary team cannot make a confident diagnosis from clinical features, lung function tests and radiological findings. The risks and benefits should be discussed with the patient.

Management of IPF

General management includes:

• Pulmonary rehabilitation: assessment includes a 6-minute walk test and a quality-of-life assessment
• Anti-fibrotic agents (pirfenidone and nintedanib): there is no conclusive evidence to support the use of any drugs to increase survival of people with IPF. However, anti-fibrotic agents have been shown to slow the decline in FVC. NICE restricts their use to patients who fulfil certain criteria: for pirfenidone, FVC must be 50-80% of predicted, whereas for nintedanib, FVC should be ≥50% of predicted. Both drugs can cause LFT derangement, and therefore, LFTs and FBC should be monitored monthly for the first 6 months, then 3 monthly. Effectiveness is monitored through FVC and TLCO
• Ambulatory or long-term oxygen therapy may be needed

Lung transplantation may be considered.

However, ultimately, management often must trend towards best supportive care, including giving information and support, symptom relief, management of comorbidities, withdrawal of ineffective therapies, and holistic end of life care.

Acute exacerbations

These are defined as worsening or acute-onset dyspnoea (<30 days) in a patient with known IPF.

As well as the chronic UIP appearances of IPF, HRCT in this context may show more acute areas of ground glass and/or extensive consolidation.

Treatment usually involves high-dose steroids with broad-spectrum antibiotic cover, as it is difficult to confidently exclude infection. Invasive ventilation of patients with known IPF is often not appropriate as outcomes are very poor.