What is idiopathic pulmonary fibrosis?
Idiopathic pulmonary fibrosis (IPF) is a chronic, progressive disease in which the delicate tissue between the air sacs of the lung becomes thickened and scarred. Scarred lung is stiff, so each breath takes more effort, and oxygen passes less easily into the blood. 'Idiopathic' means that no external cause, such as a drug, a dust exposure or an autoimmune disease, can be found.
IPF is a rare disease. It mainly affects people over the age of 60 and is more common in men and in former smokers. It is the most common of the idiopathic interstitial pneumonias and belongs to the wider group of interstitial lung diseases, many of which look similar but behave and are treated very differently.
IPF cannot yet be cured, but antifibrotic medicines now slow the rate at which lung function declines. Early, accurate diagnosis therefore matters a great deal.
Symptoms of IPF
Symptoms develop slowly over months to years and are often put down to age, weight or being unfit.
- Breathlessness on exertion: first noticed on stairs, slopes or walking briskly, and gradually worsening.
- Dry cough: persistent, irritating and often resistant to cough syrups.
- Finger clubbing: rounding of the fingertips and nail beds, seen in a proportion of patients.
- Tiredness and weight loss: more common as the disease advances.
On examination, a doctor may hear fine 'Velcro-like' crackles at the bases of both lungs. These crackles are an important early clue and should prompt a CT scan rather than repeated courses of antibiotics.
Causes and risk factors
The current understanding is that IPF results from repeated micro-injury to the lining cells of the air sacs, followed by abnormal healing that lays down scar tissue instead of normal lung. Factors that increase risk include:
- Age over 60 and male sex
- Cigarette smoking, current or past
- Long-term exposure to metal or wood dust
- Gastro-oesophageal reflux
- A family history of pulmonary fibrosis, which is linked to inherited changes in genes affecting telomeres and surfactant
Before a diagnosis of IPF can be made, other causes of lung fibrosis must be actively excluded, including connective tissue diseases such as rheumatoid arthritis and scleroderma, hypersensitivity pneumonitis from birds, moulds or air-conditioning systems, and drug-induced lung injury.
How IPF is diagnosed
Diagnosis rests on a high-resolution CT (HRCT) scan interpreted alongside the full clinical picture. International ATS/ERS/JRS/ALAT guidelines recommend that the final diagnosis is agreed at a multidisciplinary discussion involving a pulmonologist, a thoracic radiologist and, where tissue has been taken, a pathologist.
| Test | What it shows |
|---|---|
| High-resolution CT chest | The pattern and distribution of fibrosis. A 'usual interstitial pneumonia' (UIP) pattern with honeycombing at the lung bases strongly supports IPF |
| Spirometry and lung volumes | A restrictive pattern with reduced forced vital capacity (FVC), used to track progression |
| Diffusing capacity (DLCO) | How efficiently oxygen crosses from the lungs into the blood |
| Six-minute walk test | Exercise capacity and whether oxygen levels fall on exertion |
| Autoimmune blood tests | Markers of connective tissue disease that would point to a different diagnosis |
| Bronchoscopy with lavage or cryobiopsy | Used selectively when the CT pattern is not typical |
When the CT shows a typical UIP pattern in the right clinical setting, a lung biopsy is usually not needed. Bronchoscopy or transbronchial cryobiopsy is reserved for uncertain cases. Surgical lung biopsy is now needed only occasionally.
IPF treatment
Antifibrotic medicines
Two antifibrotic drugs, nintedanib and pirfenidone, slow the decline in lung function in IPF and are recommended in current guidelines. They do not reverse established scarring, which is why starting treatment early matters. Side effects such as diarrhoea, nausea, loss of appetite, skin sensitivity to sunlight and changes in liver tests are common but are usually manageable with dose adjustments and regular blood monitoring.
Treatments that are not recommended
Long-term steroids and immunosuppressants, which help several other interstitial lung diseases, do not help IPF and the combination of prednisolone, azathioprine and N-acetylcysteine was shown to be harmful. This is one reason why an accurate diagnosis is essential before treatment is chosen.
Supportive care
- Pulmonary rehabilitation to improve exercise tolerance and confidence
- Oxygen therapy when levels fall at rest or on exertion
- Smoking cessation, and vaccination against influenza, pneumococcus and COVID-19
- Treatment of reflux, sleep apnoea and pulmonary hypertension where present
- Symptom-focused palliative care for breathlessness and cough as the disease advances
Lung transplantation
Suitable patients, usually under the age of about 65 with no major other illnesses, are referred early for assessment at a lung transplant centre, as transplantation is the only treatment that replaces the scarred lung.
Outlook and follow-up
The course of IPF varies widely. Some people remain stable for years, while others decline more quickly. Regular review every three to six months, with spirometry, DLCO and walk tests, shows whether the disease is progressing and whether treatment needs adjusting.
Some patients experience an acute exacerbation, which is a sudden worsening of breathlessness over days to weeks, often without an obvious trigger. These episodes are serious and need prompt hospital assessment. Early conversations about goals of care and advance planning are part of good IPF care.
When to seek urgent care
Seek urgent medical attention for breathlessness that worsens noticeably over days, new breathlessness at rest, a fall in home oxygen readings, fever with increasing cough, chest pain, coughing up blood, or swelling of the ankles. Sudden worsening in IPF may be an acute exacerbation, an infection, a pulmonary embolism or a pneumothorax, all of which need same-day assessment.
Frequently asked questions
Is idiopathic pulmonary fibrosis the same as interstitial lung disease?
IPF is one specific type of interstitial lung disease. The term interstitial lung disease covers more than 200 conditions, many of which respond to steroids or immunosuppression, whereas IPF does not. Correct classification is therefore essential.
Can IPF be cured?
There is currently no cure apart from lung transplantation in selected patients. Antifibrotic medicines such as nintedanib and pirfenidone slow the rate of decline in lung function, and supportive care improves symptoms and quality of life.
Do I need a lung biopsy to confirm IPF?
Often not. When the HRCT scan shows a typical usual interstitial pneumonia pattern and other causes have been excluded, the diagnosis can be made at a multidisciplinary discussion without a biopsy. Biopsy is considered when the scan pattern is uncertain.
Is IPF infectious or related to tuberculosis?
No. IPF is not an infection and cannot be passed to others. In India, lung scarring is sometimes assumed to be old tuberculosis, but the pattern of IPF on CT is different and needs specialist interpretation.
Will I need oxygen at home?
Not everyone does. Oxygen is prescribed when blood oxygen levels fall at rest or during activity, which is checked with a walk test and pulse oximetry at follow-up visits.
Should my family be tested?
If two or more family members have pulmonary fibrosis, this may be familial pulmonary fibrosis. Genetic counselling and assessment of relatives can be discussed, although routine screening is not needed in most cases.
Related conditions and procedures
Consult Dr. Gogineni Ratnakara Rao
Apollo Hospitals, Financial District: Monday to Saturday, 8:30 AM to 5:00 PM. Anything in Lung Clinic, Chanda Nagar: Monday to Saturday (Thursday closed), 6:00 PM to 9:00 PM.