Pulmonary fibrosis stages

Understanding pulmonary fibrosis

Pulmonary fibrosis (scarring) is a chronic lung disease marked by lung tissue scarring and thickening, which impairs lung function and makes breathing progressively harder.

The damage to the lungs prevents oxygen from efficiently passing into the bloodstream, leading to reduced oxygen absorption and overall respiratory distress.

Factors like:

• Toxins, including cigarette smoke
• Radiation therapy
• Medications, or
• Other medical conditions that has a significant risk factor

can cause lung damage and fibrosis. However, in many cases, the cause is unknown, known as idiopathic.

Idiopathic pulmonary fibrosis (IPF) and other progressive pulmonary fibrosis are particularly challenging due to the irreversible nature of the lung tissue damage, making symptom management and slowing disease progression essential. Recognising and intervening early can significantly improve the quality of life for those affected.

Identifying the stages of pulmonary fibrosis

Pulmonary fibrosis can progress differently for each person—some people’s symptoms worsen quickly, while others stay stable for a long time. Doctors often use a simple staging system based on lung function tests to classify the condition into four stages: mild, moderate, severe, and advanced. These stages help guide the best treatment approach for each patient.

Understanding the stages and how symptoms progress is important in deciding when to start treatments like pirfenidone and nintedanib which can help slow the disease. Tracking lung function over time provides a clearer understanding of how things are progressing, enabling doctors to choose the most effective treatment and dosage, helping improve outcomes for patients.

The GAP model: a tool for assessing severity

The GAP model, which stands for Gender Age Physiology, is a widely used framework for assessing the severity of idiopathic pulmonary fibrosis.

This scoring system incorporates four baseline variables, including lung physiology variables:

1. Gender
2. Age
3. Forced vital capacity (FVC)
4. Diffusing capacity of the lungs for carbon monoxide (DLCO).

By considering these factors, the GAP index helps predict health outcomes and can guide treatment strategies.

Despite its usefulness, the GAP model is not really a clinical staging system for pulmonary fibrosis, but more of a tool for stratifying patients for research. However, it can provide a guide, albeit potentially a crude guide, to predict the accuracy of patient outcomes. There are slightly different scoring systems for IPF and for other interstitial lung diseases. In all cases, being male, being older and having worse lung function puts any individual in a worse prognostic group.

Symptoms across different stages

As pulmonary fibrosis progresses, the severity of symptoms worsen, significantly impacting the quality of life. Recognising symptoms at each stage is vital for timely diagnosis and best management.

Symptoms can vary widely, with some individuals experiencing a gradual worsening over time while others may notice a more rapid decline.

Pre-clinical or interstitial lung abnormalities (ILA)

Occasionally, patients have CT scans of the lungs for other reasons, for example, national lung cancer screening programmes, which may pick up early signs of interstitial lung changes before the changes have reached clinically significant levels to be called an interstitial lung disease (ILD). Patients are usually asymptomatic, but may be referred to an ILD service to be watched carefully to see if the ILAs progress to an ILD.

Early stage symptoms

In the early stages of idiopathic pulmonary fibrosis and other interstitial lung diseases, symptoms are often subtle, but persistent. A common early sign is a dry cough that does not seem to go away. Mild shortness of breath, particularly during physical exertion, is another hallmark symptom, leading individuals to mistakenly attribute it to aging or being out of shape. These mild symptoms can lead to decreased activity levels due to the worsening shortness of breath.

Identifying these early symptoms help in timely diagnosis, enabling early treatments to slow disease progression and manage symptoms more effectively. Early diagnosis is key to improving longterm outcomes.

Intermediate stage symptoms

As the disease progresses, symptoms become more pronounced. Increasing breathlessness, signifying a decline in lung function, makes daily activities more and more challenging. Patients may notice tasks that were once easy now require considerable effort, leading to a more sedentary lifestyle.

This stage is also marked by a decreased exercise tolerance and persistent dry cough. These symptoms greatly affect quality of life, as patients find it difficult to complete everyday tasks and may face emotional distress due to their worsening physical abilities.

Advanced stage symptoms

In the advanced stages of pulmonary fibrosis, symptoms become severe and debilitating. Significant shortness of breath occurs even at rest, and individuals may require oxygen therapy to assist with breathing. Simple activities, such as dressing or walking short distances, can trigger intense breathlessness.

Patients may also have clubbing, a condition characterised by the widening and rounding of the tips of fingers or toes, indicating severe disease. Managing advanced symptoms is essential for maintaining quality of life and providing comfort.

Diagnostic tools for staging pulmonary fibrosis

Diagnosing and staging pulmonary fibrosis involves a combination of clinical assessments, pulmonary function tests, imaging techniques and sometimes lung biopsy. These tools are essential for guiding doctors to choose the appropriate treatment options and for monitoring disease progression.

Pulmonary function tests

Lung function tests are important for checking how well the lungs are working and how much damage has been done in people with pulmonary fibrosis. A common test, called spirometry, measures how much air you can breathe in and out and can show signs of lung stiffness. In people with pulmonary fibrosis, the total lung capacity is usually lower, which helps doctors understand the severity of the disease.

These tests are important for diagnosing pulmonary fibrosis and assessing disease progression. Regular pulmonary function tests monitor lung function changes over time, guiding treatment decisions and ensuring timely interventions.

Imaging techniques

Imaging techniques, particularly high-resolution computed tomography scans, or CT scans, play a critical role in diagnosing and staging pulmonary fibrosis. These scans provide detailed images of the lungs, highlighting the extent of lung damage and scarring that may not be visible on standard X-rays.

High-resolution CT scans have significantly enhanced the accuracy of diagnosing and staging pulmonary fibrosis. Imaging results, combined with clinical assessments and pulmonary function tests, provide a comprehensive picture of the patient’s condition.

At UCLH, we have the first in the world programme of molecular imaging in interstitial lung disease. Radiolabelled glucose is taken up in fibrotic and inflammatory areas of the lung and may offer a novel biomarker that can report prognosis and may even show the response of individual patients to treatment.

Lung biopsy

When imaging results are inconclusive, a lung biopsy may be necessary for a definitive diagnosis of pulmonary fibrosis. Indications for a lung biopsy include unexplained respiratory symptoms, persistent chest imaging abnormalities and the need to rule out other conditions.

The procedure can be performed using various methods, such as relatively non-invasive cryoscopic lung biopsy in some centres, or video-assisted thoracoscopic surgery (VATS), needle biopsy or open lung biopsy. Though lung biopsies carry risks like bleeding, infection and pneumothorax, they may offer crucial information for accurate diagnosis and treatment planning. UCLH and other lung specialist centres offer robot-directed cryoscopic lung biopsy which makes biopsy much safer.

Treatment options by stage

Treatment options for pulmonary fibrosis vary depending on the stage of the disease. While there is no cure, treatments aim to relieve symptoms and slow disease progression, and are tailored to the severity of the condition. Medications like pirfenidone and nintedanib are prescribed for all cases of idiopathic pulmonary fibrosis unless the risks outweigh the benefits. These drugs do not reverse the fibrosis, but may help to slow disease progression and have a small, although inconsistent, impact on symptoms. Nintedanib is also available for other forms of interstitial lung disease that are characterised by pulmonary fibrosis, other than idiopathic pulmonary fibrosis, and that have been shown to be progressive, despite other medication.

Early intervention strategies

Early intervention is crucial in managing pulmonary fibrosis effectively. Physical activity, such as walking or using a stationary bike, can improve lung function and reduce stress. A heart-healthy diet and smaller, more frequent meals can enhance overall health and alleviate breathing difficulties.

Mental health care is also essential, as managing the emotional toll of pulmonary fibrosis can significantly impact a patient’s quality of life. Avoiding triggers, like poor air quality and high altitudes, can help prevent worsening of symptoms.

Medications like pirfenidone and nintedanib are prescribed for mild to moderate idiopathic pulmonary fibrosis, helping to slow disease progression and manage symptoms. Nintedanib is also available for other forms of pulmonary fibrosis that have been shown to be progressive, despite other medication.

Moderate disease management

Managing moderate pulmonary fibrosis involves a combination of medications and lifestyle changes. Patients may experience a noticeable decline in their ability to engage in physical activities due to increased breathlessness. Common symptoms include a persistent dry cough and tiredness during everyday tasks, leading to a more sedentary lifestyle. Ambulatory oxygen, which means oxygen from a portable concentrator or cylinder, can be used to increase exercise and may be prescribed at this point in certain patients. Patients may be offered the chance to take part in a clinical trial to evaluate novel therapies in addition to the standard treatments.

Advanced treatment approaches

For severe pulmonary fibrosis, advanced treatment choices are necessary. Lung transplantation is an option for a small handful of younger and fitter patients with severe progressive disease, offering a chance for improved lung function and quality of life.  For other patients, there is a constant search for new therapeutic modalities that may enhance lung function and quality of life, and some patients may consider taking part in clinical trials of these agents. 

Complications associated with  pulmonary fibrosis

Pulmonary fibrosis can lead to several complications, significantly affecting health. Pulmonary hypertension, where the lung arteries become stiff and thick, increases pressure on the heart and complicates the disease. Respiratory failure, characterised by dangerously low oxygen levels in the blood, is another critical complication as the disease progresses.

Acute exacerbation can cause sudden worsening of symptoms, which could be potentially life-threatening if not managed promptly. Severe pulmonary fibrosis may also result in lung infections, blood clots or even a collapsed lung.

Improving quality of life for pulmonary fibrosis patients

Improving life for people with pulmonary fibrosis involves a range of care strategies. Pulmonary rehabilitation programs can help manage symptoms and improve daily activities, making a big difference in overall quality of life.

Oxygen therapy is beneficial for maintaining better oxygenation levels in patients experiencing low blood oxygen levels, and proper oxygenation during sleep and exercise can reduce pulmonary hypertension.

Palliative care offers symptom relief and support at all stages, focusing on enhancing comfort for patients. Encouraging patients to quit smoking and get vaccinated against COVID, Respiratory Syncytial Virus (RSV), influenza and pneumococcal infections can prevent additional respiratory complications.

Support groups offer valuable resources and emotional support, helping patients cope with the challenges of pulmonary fibrosis. Check out support groups from Asthma and Lung UK and Action for Pulmonary Fibrosis.

Prognosis and survival rates

The prognosis and survival rates for pulmonary fibrosis can vary depending on factors such as the patient’s overall health and how quickly the disease progresses. Advances in diagnosing and treatment led to improved cumulative survival rates in the 2010s compared to the previous decade. Age, comorbidities and disease stage significantly influence prognosis, with higher GAP scores, correlating with increased mortality risk scoring. For those who currently live with idiopathic pulmonary fibrosis, the cumulative survival rate after three years is around 62%, with about 46% living beyond five years. While mortality rates have been rising globally, treatments like medication and pulmonary rehabilitation are helping manage symptoms and extend life expectancy.

Preventive measures and risk factors

Understanding and preventing pulmonary fibrosis is important for managing the disease. Longterm exposure to harmful substances, certain medical treatments and smoking are known risk factors for developing idiopathic pulmonary fibrosis. Environmental and workplace pollutants can also play a role in the development of the disease.

Living a healthy lifestyle—such as eating a balanced diet, exercising regularly and quitting smoking—can help lower the risk of pulmonary fibrosis. Educating patients about these risk factors and preventive measures is key to reducing the chances of developing the condition.