What is Idiopathic Pulmonary Fibrosis?
Idiopathic pulmonary fibrosis (IPF) is a lung condition where the lungs get scarred for no known reason. This disease tends to get worse over time, and often leads to poor health outcomes in the long run. Signs of IPF usually include increasingly short breath, difficulty breathing that gets worse over time, and a dry cough that doesn’t produce any mucus.
Pulmonary function tests, a group of tests that measures how well your lungs are working, often show a decrease in lung function, a reduction in the maximum amount of air an individual can use for breathing, and a reduced ability for the lungs to transfer air and blood. Detecting this disease early is very important for treating it effectively, as the disease can worsen quickly in its later stages. Most of the time, doctors can diagnose the disease without needing to take a tissue sample (biopsy) by looking at the patient’s medical history, results from imaging tests like CT scans, and by ensuring that other possible diseases aren’t causing the symptoms.
CT scans, a special type of x-ray that makes detailed pictures of areas inside the body, often show patterns of scarring (fibrosis) in the outer edges of the lungs, especially at the bottom. In some cases, a lung biopsy may be necessary if the diagnosis is still unclear.
However, lung biopsies come with risks and are usually not performed for patients who have just been diagnosed with interstitial lung disease (a group of lung disorders causing scarring) if a “usual interstitial pneumonia” (a typical pattern of scarring and inflammation) shows on high-resolution CT scans. Treatment options include remedies to relieve symptoms, providing extra oxygen if necessary, medications that prevent further scarring, and in serious cases, a lung transplant. A lung transplant is currently the only known treatment option that can potentially cure this disease.
What Causes Idiopathic Pulmonary Fibrosis?
The exact cause behind a lung disease called IPF, which stands for “idiopathic pulmonary fibrosis,” is unknown. A noticeable feature of IPF is the abnormal behavior of cells called fibroblasts, which start depositing an extra net of substances outside of themselves.
The current theory suggests that when the thin walls of the air sacs in our lungs, known as alveoli, get repeatedly damaged, our immune system responds by creating fibroblasts. Other factors that may play a role in IPF include issues with DNA repair and problems with proteins that help manage the surface tension inside our lungs.
If the body’s responses to the lung damage become unregulated, the tissue in the fibrotic, or scarred, areas can remodel. This process could be caused by a variety of mechanisms. Considering fibroblasts specifically, they could increase in number due to changes in other cells, invasion by a type of cell known as fibrocytes, or simple expansion.
IPF onset is due to both the built-in and the adaptive immune systems. Crucial built-in immune cells in IPF include types of white blood cells and fibrocytes, which ultimately turn into fibroblasts. Meanwhile, responses and chemicals related to the adaptive immune system are involved in causing IPF. All these processes increase factors that promote fibrosis, like certain chemicals in the body called interleukins and the transforming growth factor. Certain other cells help continue the inflammation, which is believed to activate lung cells ultimately leading to an excess accumulation of fibroblasts.
What triggers inflammation often has to do with exposure to cigarette smoke and air pollution. Aging is also a primary risk factor for IPF, as with aging, the supply of stem cells and pericytes, both of which offer protective functions, run low. This depletion can make people more prone to fibroblast activation and growth. Furthermore, several studies have suggested a connection between thyroid issues and fibrosis in different organs, including the lungs.
IPF involves several genes necessary for lung development and response to environmental damage, including WNT, TGF, Notch, and sonic hedgehog. There are also genes involved in the inflammatory process, some of which include the Toll-interacting protein and the inhibitory protein of the Toll-like receptor signaling pathway.
Although most IPF cases appear without a clear cause, some genetic factors contributing to cases that run in families have been identified. Mutations in the telomerase genes (like TERT), surfactant genes (like SFTPA2), and mucin genes (like MUC5B) have been known to cause pulmonary fibrosis. Hermansky-Pudlak syndrome is another rare genetic disorder that leads to certain characteristic features and often causes pulmonary fibrosis in affected individuals.
Risk Factors and Frequency for Idiopathic Pulmonary Fibrosis
Idiopathic Pulmonary Fibrosis (IPF) is a condition usually seen in older people, particularly those over the age of 50. It is found more frequently in males than in females. The number of IPF cases observed varies depending on the region, with Europe having between 0.33 to 2.51 cases and North America having between 2.40 to 2.98 cases per 10,000 people. In the United States, about 14.6 new cases occur per 100,000 people each year, and 58.7 existing cases are observed per 100,000 people.
The number of people with IPF generally goes up with age. Most patients are over the age of 50, and up to 85% are more than 70 years old. There is a type of IPF that runs in families and tends to affect individuals at a younger age. However, this form of the condition is much less common, making up only 3.7% of cases. Each year, between 2.3 and 5.3 new cases of IPF appear per 100,000 people.
Signs and Symptoms of Idiopathic Pulmonary Fibrosis
Idiopathic Pulmonary Fibrosis (IPF) mainly affects older adults aged 60 and above, though younger individuals with a family history of IPF are also susceptible. Useful information during medical assessment includes a family history of premature aging signs like early graying of hair, as well as any known contact with harmful substances like dust, metals, asbestos, mold, or birds.
Most people suffering from IPF experience shortness of breath, cough, and fatigue. But because these symptoms are quite general, diagnosis often gets delayed over a year from when symptoms first appear. Therefore, it’s very important to rule out other diseases before diagnosing IPF.
When assessing a suspected case of IPF, doctors need to gather a detailed account of the patient’s medication use, especially drugs linked to lung damage such as amiodarone and bleomycin. Sign of rheumatic diseases are also crucial to look for. These include:
- Joint pain or swelling
- Digital ulcers
- Dry eyes and mouth
- Fatigue
- Fever
- Hair loss
- Muscle weakness or pain
- Sensitivity to light
- Raynaud phenomenon
- Skin thickening
- Small red spots on the skin
It’s also important to consider other conditions that can lead to lung problems, like scleroderma, Sjögren’s disease, and polymyositis/dermatomyositis.
During a physical exam, doctors focus on evaluating lung function, assessing how advanced the disease is and ruling out other potential diagnoses. Key indicators include a specific crackling sound in the lungs during inspiration, as well as ‘clubbing’ of the fingers. To rule out autoimmune disorders, doctors look for signs such as skin rashes, joint swelling, sclerodactyly (thickening and tightness of the skin on the fingers and hands), Raynaud’s phenomenon (where fingers turn white or blue in cold temperatures), and muscle weakness. In severe cases of IPF, patients may show exercise intolerance, even with minor exertion, or reduced oxygen levels even at rest.
Testing for Idiopathic Pulmonary Fibrosis
The diagnosis of Idiopathic Pulmonary Fibrosis (IPF), a lung disease that causes lung tissues to become damaged and scarred, usually depends on assessing symptoms and risk factors like exposure to harmful airborne substances and signs of conditions that affect the body’s connective tissues (like rheumatoid arthritis, rashes, or skin-related issues). However, various medical tests can also be used to help confirm the diagnosis.
Let’s discuss these tests in a simplified way:
Pulmonary Function Tests (PFTs) are often carried out to check for problems in the lungs that cause them to be tight and make it hard to breathe fully (known as restrictive lung disease). This condition causes a drop in various lung measurements (most importantly the total volume of air that the lungs can hold, and how much air can move in and out of the lungs). Other conditions that may cause similar lung restriction include abnormalities in the chest wall (like excessively curved spine, known as kyphoscoliosis), obesity, and conditions causing muscle weakness.
If IPF is suspected, doctors often order lab tests that can rule out conditions affecting the immune system. Common tests may check for immune system substances (antibodies) that attack normal cells, such as antinuclear antibodies and rheumatoid factors. Yet, if doctors strongly suspect an autoimmune disease, they may order additional tests. Furthermore, people diagnosed with Short Telomere Syndrome (a condition that leads to premature aging of cells) should be checked periodically for bone marrow and liver problems. Family members may also need tests to measure the length of their telomeres, parts of DNA that protect our genetic data.
Imaging tests, like x-rays and high-resolution computed tomography (HRCT), are critical for diagnosing IPF. X-rays may not provide enough detail to confirm IPF. HRCT, which provides more detailed images of your lungs, can help identify characteristic features of this disease. The main feature observed on HRCT imaging is a specific pattern called UIP. If the images show other features such as unclear regions or consolidations, it should raise suspicion for diseases other than IPF.
Due to a high occurrence of coronary artery disease (CAD) in IPF patients, a method to calculate the build-up of calcium in the coronary arteries might be considered. Low-dose scanning strategies have been developed to reduce radiation exposure, especially for patients needing repeated imaging.
If other methods are not sufficient to confirm IPF, American Thoracic Society guidelines suggest considering a surgical lung biopsy unless the patient has a significant risk for complications. A biopsy procedure involves taking a small sample of lung tissue to examine under a microscope.
A type of bronchoscopy procedure called transbronchial lung cryobiopsy (TBLC) is another option for tissue sampling, but it’s suitability varies according to the patient. Recently, a set of recommended criteria was put together to help guide when a patient is suitable for TBLC or surgical lung biopsy.
Finally, a Multidisciplinary Discussion (MMD) involving various specialists can enhance diagnostic accuracy and play a key role in detecting IPF. A lung biopsy may be required if clinical assessment, lab testing, and HRCT don’t lead to a confident diagnosis.
Treatment Options for Idiopathic Pulmonary Fibrosis
Research indicates that patients with advanced stages of idiopathic pulmonary fibrosis (IPF), a type of lung disease that results in scarring (fibrosis) of the lungs, can experience a rapid decline in lung function despite receiving treatment. Therefore, it’s important to diagnose and start treating IPF early when it might be more successful in slowing down the disease’s progression.
To track the disease, patients can take pulmonary function tests (PFTs) every 3 to 6 months, depending on their symptoms and how their disease is progressing. There’s also a scoring system called the GAP score, determined through a patient’s gender, age, and two respiratory tests: forced vital capacity (FVC), which measures how much air you can forcibly exhale from your lungs, and diffusing capacity, which assesses how well oxygen passes from your lungs to your bloodstream. A higher GAP score can suggest a worse outcome. This score is especially useful when evaluating patients for lung transplant referrals.
Non-surgical treatments include quitting smoking, getting more oxygen, and a program of exercise, education, and support called pulmonary rehabilitation. While extra oxygen is often suggested for severe cases of lung disease, like IPF, there’s limited data that can guide its use in this specific population. Numerous studies have shown the benefits of pulmonary rehabilitation for people with various types of lung disease, including IPF. However, the quality of these findings is considered moderate to low due to concerns about how the studies were conducted.
In terms of medications for managing symptoms, antacid medication can be beneficial for patients who have gastroesophageal reflux disease (GERD) symptoms alongside IPF. For patients with IPF, flu shots and pneumonia vaccines are recommended. Two antifibrotic (anti-scarring) drugs, pirfenidone and nintedanib, are approved for use in IPF. Studies have shown that both drugs can slow disease progression and potentially reduce overall mortality and sudden disease flare-ups.
Patients with advanced IPF might be referred for a lung transplant early in the course of the disease, especially if they’re experiencing a steady decline in lung function. Studies have shown that a lung transplant can potentially extend survival for patients with IPF.
There are also a few additional treatments available. Acute exacerbations, which are sudden worsenings of the disease leading to a rapid decline in lung function, can occur in IPF. When these happen, it’s important to rule out other causes like heart failure and to treat potential infections and blood clots in the lungs (thromboembolic disease) promptly.
Lastly, palliative care, care designed to make you comfortable and help ease symptoms, but not to cure the disease, is highly recommended for people with advanced IPF. Studies have shown that palliative care can make symptom management, quality of life, and end-of-life care better for individuals with IPF. Currently, a few potential treatments for IPF are being investigated, such as drugs that could prevent or stop the formation of fibrosis and fibroblast (cells that produce collagen and other fibers), but these are still in early testing stages.
What else can Idiopathic Pulmonary Fibrosis be?
When your doctor is trying to figure out if you have Idiopathic Pulmonary Fibrosis (IPF), they will also consider other illnesses that have similar symptoms. These conditions include:
- Work-related lung diseases like pneumoconiosis and asbestosis
- Inflammation in the lungs due to accidentally breathing in food or drink (Aspiration pneumonitis)
- Bacterial and viral pneumonia
- ‘Farmer’s lung’ and other types of hypersensitivity pneumonitis
- Fungal infections in the lungs
- Lung cancer
- Pneumocystis jiroveci pneumonia, which is a fungal infection common in people with weakened immune systems
- Sarcoidosis, a disease that causes inflammation in organs
- Pulmonary edema, which is when fluid builds up in the lungs
- Connective tissue diseases
What to expect with Idiopathic Pulmonary Fibrosis
Idiopathic Pulmonary Fibrosis (IPF), a condition that keeps getting worse with time, has an average survival time of about 5 years. That being said, roughly 20% of patients can survive without treatment. The unpredictability of the disease’s progression, the severity of symptoms, and its generally bad outlook significantly impact the patient’s and their families’ quality of life.
The survival rate for IPF has shown some improvement since 2010, which could be due to treatments that help control fibrosis (scarring and hardening of tissues) in the lung and earlier detection of the disease.
However, individual survival rates can vary greatly, with around 20% to 25% of patients living more than 10 years after being diagnosed. Despite this, most patients still struggle with breathlessness and limited ability to exercise, leading to a poor quality of life. Deaths are more common in winter, even when there is no lung infection. Many patients develop pulmonary hypertension, a type of high blood pressure that affects the arteries in the lungs and the right side of the heart, which increases their risk of a pulmonary embolism (a sudden blockage in a lung artery) and sudden heart-related death. Those with severe changes seen in medical imaging and who don’t respond well to oxygen treatment tend to have a worse outlook.
Possible Complications When Diagnosed with Idiopathic Pulmonary Fibrosis
Complications from idiopathic pulmonary fibrosis (IPF) may include high blood pressure in the lungs, blood clots in the lungs, medication side effects, additional lung infections, heart attack, and low oxygen levels leading to breathing failure.
Common Complications:
- High blood pressure in the lungs (pulmonary hypertension)
- Blood clots in the lungs (thromboembolic disease)
- Side effects from medications
- Additional infections in the lungs
- Heart attack (acute coronary syndrome)
- Low oxygen levels leading to breathing failure (hypoxic respiratory failure)
Preventing Idiopathic Pulmonary Fibrosis
At present, there are no specific guidelines for regular screenings or prevention measures for F. However, if you’re diagnosed with IPF (Idiopathic Pulmonary Fibrosis – a lung disease that results in lung scarring), you should stick to these recommendations:
First, it’s important to maintain a healthy weight and indulge in regular physical exercises. Pulmonary rehabilitation, which is a formal exercise program, could also be helpful.
If you’re a smoker, you should try to quit – smoking can worsen your lung condition.
Also, you should try to avoid places or occupations that might expose you to things that can worsen your lung disease.
If you suffer from acid reflux, make sure to manage it as needed. Acid reflux occurs when stomach acid frequently flows back into the tube connecting your mouth and stomach.
You need to continue disease-specific treatments and consider getting a lung transplant if referred by your doctor.
Lastly, make sure to get vaccinated for the flu, pneumonia, and COVID-19. People with IPF have less lung capacity to manage respiratory infections and hence preventive steps like vaccinations are crucial.