What is Interstitial Pulmonary Fibrosis?
Nonidiopathic interstitial pulmonary fibrosis (non-IPF), in simple terms, refers to a set of lung disorders that cause inflammation and scarring in the areas of the lung where gas exchange occurs, due to an identifiable cause. This means it becomes more difficult for oxygen to move from your lungs into your blood. Depending on the exact type of disorder, it might also affect various parts of the lungs, including the windpipe, bronchi (large air passages), bronchioles (small air passages), air sacs in the lung (alveoli), and the lining around your lungs (pleura).
Most of these diseases can be characterized using clinical observations, imaging scans, cellular study (pathology), and physical tests. The common symptoms often include a gradual increase in shortness of breath and cough. Abnormal findings in chest images and signs of inflammation and scarring under microscopic examination are often seen. Lung function tests (PFTs) often indicate a restrictive pattern, meaning the lungs struggle to take in a full — breath and a decreased ability to transfer inhaled oxygen into the bloodstream (DLCO).
What Causes Interstitial Pulmonary Fibrosis?
There are more than 200 known causes of non-IPF, a type of lung disease not related to a specific cause called Idiopathic pulmonary fibrosis (IPF). These causes are often sorted into several categories.
Exposure to certain materials or substances at work or in the environment can lead to this lung disease. This includes:
– Asbestos, often encountered by plumbers, shipyard and construction workers.
– Beryllium, a substance handled by aerospace workers and miners.
– Carbon dust, commonly found in coal mines.
– Silica, encountered in mining and sandblasting occupations.
– Chromium, used in metal and chemical manufacturing.
– Certain organic substances like fungi, bird droppings, and specific bacteria (B. subtilis, B. cereus).
Several drugs can also cause lung toxicity, leading to interstitial pulmonary fibrosis, a type of lung disease. These include medications like amiodarone, cancer-fighting drugs, beta-blockers, nitrofurantoin, statins, and exposure to radiation therapy.
The disease can also be caused by connective tissue diseases (CTD). These are a group of disorders that affect the tissues that serve as a framework for your body. They include conditions such as systemic lupus erythematosus (SLE), systemic sclerosis, rheumatoid arthritis, antisynthetase syndrome, polymyositis/dermatomyositis, and mixed connective tissue disease.
Lastly, some systemic illnesses can lead to this type of lung disease. These conditions include sarcoidosis, pulmonary Langerhans cell histiocytosis, lymphangiomyomatosis, granulomatosis with polyangiitis, anti-glomerular basement membrane antibody disease, chronic aspiration, and alveolar proteinosis.
Risk Factors and Frequency for Interstitial Pulmonary Fibrosis
Pulmonary fibrosis, which can come in various types, is slightly more common in men than women. It often starts affecting people in their fifties or sixties. This is a trend seen not only in the United States, but also globally. There are 31.5 new cases annually per 100,000 men and 26.1 new cases per 100,000 women. The total number of people living with the disease at a given time, known as the prevalence, is between 25 to 74 per 100,000 people.
Signs and Symptoms of Interstitial Pulmonary Fibrosis
Non-Idiopathic Pulmonary Fibrosis (non-IPF) is a lung condition that typically affects people in their fifties or sixties. The symptoms are often vague, including shortness of breath and a persistent cough. Some people may also experience wheezing, chest pain, or coughing up blood. These signs can develop over weeks or even years, and they are often linked to long-term exposure to certain substances or having an autoimmune disease. When diagnosing the cause of non-IPF, it’s important to learn about a patient’s family history with autoimmune diseases, medication and smoking use, potential radiation exposure, and job-related exposures.
The causes discussed are linked to ongoing inhalation of natural and unnatural substances, medicine-related toxicity, connective tissue diseases, and systemic illnesses. Patients might also have symptoms unrelated to their lungs, which might help to pinpoint the diagnosis. Examples include scleroderma and Raynaud’s phenomenon in systemic sclerosis.
Physical check-ups might be normal or might alternately vary depending on the disease. Here is a list of symptoms that a patient might have:
- General symptoms: Rapid breathing and blueish skin color or lips if low on oxygen. In cases of connective tissue diseases or sarcoidosis, there may be a fever.
- Head, ears, eyes, nose, and throat symptoms: Sinus infection symptoms in eosinophilic granulomatosis with polyangiitis (Churg-Strauss syndrome). Eye symptoms, including uveitis and retinal vasculitis, might be associated with sarcoidosis.
- Lungs/thorax symptoms: Fine crackling sounds in the lungs at the end of a breath. If the airway is involved (like in Churg-Strauss syndrome or hypersensitivity pneumonitis), there might be a wheezing sound.
- Musculoskeletal symptoms: Enlarged fingertips is a common and nonspecific finding. Patients with connective tissue diseases may show muscle weakness typically seen in polymyositis, Raynaud’s phenomenon in systemic sclerosis, and other joint abnormalities.
- Neurological symptoms: In the case of sarcoidosis, the patients may experience cranial and/or peripheral nerve damage. Asymmetric nerve damage often presents in Churg-Strauss syndrome.
- Skin symptoms: Most skin symptoms in non-IPF patients are related to connective tissue or systemic diseases. Skin inflammation is a characteristic of eosinophilic granulomatosis with polyangiitis. A thickening of skin and facial spider veins are indications of scleroderma. Skin thickening coupled with Raynaud’s phenomenon suggests systemic sclerosis. A purple- or red-colored rash on the upper eyelids, the face, and body points to dermatomyositis. Red, painful bumps on the skin indicate cutaneous sarcoidosis. In rheumatoid arthritis, there may also be touchable lumps beneath the skin.
Testing for Interstitial Pulmonary Fibrosis
If your doctor suspects that you have a non-IPF related condition (IPF stands for Idiopathic Pulmonary Fibrosis – an illness which damages your lungs), they will need to carry out a range of medical tests. This can sometimes include an invasive procedure known as a biopsy, which is where a small sample of tissue is taken for closer examination. What kind of tests your doctor chooses will depend on your personal medical history and any physical symptoms you’ve been experiencing.
Your doctor will start off with basic laboratory tests, checking your blood count, electrolyte levels, and kidney and liver functions. If your symptoms and medical history suggest that your immune system might not be working properly – such as joint pain, fever, fatigue or weight loss – you’ll need further blood tests. These tests will look for certain proteins that the body produces when it identifies something wrong. If one of these markers, known as ANA, seems high, then your doctor might suggest further tests to find out more about what could be causing your symptoms.
There might be other blood tests too. For instance, if your doctor suspects you have a condition called sarcoidosis, they might check your blood for a chemical called angiotensin-converting enzyme. However, this test isn’t always useful, so may not be included. If your doctor is worried that you might have a condition where your lungs react to certain substances, they might also check your blood for particular antibodies.
Imaging, like x-rays and scans, can be really useful in diagnosing non-IPF conditions. Early on in some diseases, these images might look normal. However, as the condition progresses, your doctor might start to see specific changes on the images, like changes in the size of your lungs, certain patterns or perhaps the lymph nodes in your chest look larger than they should. One kind of chest scan, called a high-resolution computed tomography (HRCT), can be particularly helpful in confirming some lung diseases. The patterns this scan picks up, along with details from your medical history, often allow doctors to make a precise diagnosis and find out how far the disease has progressed. There are certain tell-tale signs that the doctors look for in these scans, like a “ground-glass” appearance or a pattern known as “honeycombing”.
If it’s still unclear what’s causing your symptoms, your doctor might need to examine some fluid from your lungs (this fluid is called “bronchoalveolar lavage”) or small bits of lung tissue (this is known as “transbronchial lung biopsy”). Rarely, your doctor might request a surgical biopsy, but this is a more invasive procedure and generally only done if other tests haven’t given clear results.
All patients who might have a non-IPF condition should have lung function testing. This will give an idea of the severity of your condition and how quickly it is progressing. These tests are done at resting and during activity and will need to be repeated regularly to monitor your condition.
Treatment Options for Interstitial Pulmonary Fibrosis
Chronic disease management mainly involves supportive measures that aim to improve the patient’s quality of life. To manage chronic illnesses, it’s recommended that patients quit smoking, get influenza and pneumococcal vaccinations, undergo pulmonary rehabilitation, and avoid harmful agents, such as certain medications.
When patients’ oxygen levels in the blood drop significantly, supplemental oxygen therapy could become necessary. The treatments can differ based on the specific diagnosis of the chronic condition. In certain situations, corticosteroids, which are medications that reduce inflammation, may be used. For severe cases, a lung transplant might be considered as an option, and it’s advised that patients are evaluated early to be placed on the transplant waiting list.
If the disease worsens suddenly, the patient could experience acute respiratory failure, where the body is not getting enough oxygen. To cope with this, supplemental oxygen is provided, and corticosteroids are typically administered intravenously (directly into the bloodstream). In severe cases or if the disease is progressing quickly, another medication known as cyclophosphamide may be used as a secondary treatment or as the primary treatment if the lung disease is caused by inflammation of the blood vessels.
What else can Interstitial Pulmonary Fibrosis be?
Possible causes of respiratory difficulties could be due to a variety of conditions including:
- Infections
- Pulmonary embolism (blockage in the lungs)
- Heart failure with a reduced ejection fraction (heart not pumping blood effectively)
- Acute respiratory distress syndrome (sudden severe difficulty in breathing)
- Chronic obstructive pulmonary disease (long-term lung disease)
- Idiopathic pulmonary fibrosis (scarring of the lungs)
- Aspiration pneumonitis/pneumonia (inflammation or infection due to inhalation of foreign matter)
- Malignancy (cancer)
- Pulmonary edema (excess fluid in the lungs)
- Pneumocystis pneumonia (type of lung infection)
What to expect with Interstitial Pulmonary Fibrosis
The outlook and death rates of a disease can vary a lot. They depend on many factors such as the cause of the disease, how severe it is, how fast it progresses, lung function tests including DLCO (a test to check how well your lungs are working), availability of medical treatments, and presence of any other medical conditions. In some severe cases, the death rates can be as high as 100% during a sudden worsening of non-IPF (a type of lung disease not related to Idiopathic Pulmonary Fibrosis). This can happen due to specific causes like connective tissue diseases or hypersensitivity pneumonitis (a type of lung inflammation). Death rates in all types of non-IPF diseases get higher when one encounters acute respiratory failure, a severe condition where the amount of oxygen reaching the lungs is not sufficient.
Possible Complications When Diagnosed with Interstitial Pulmonary Fibrosis
Numerous complications can happen based on the specific causes, especially in people with widespread diseases. Here are some of the known complications experienced by individuals with nonidiopathic interstitial pulmonary fibrosis, a lung disease:
- Acute (sudden) and/or chronic (long-term) breathing failure
- Permanent scarring of the lungs, also known as pulmonary fibrosis
- High blood pressure in the lungs, referred to as pulmonary hypertension
- Increased pressure in lung arteries known as pulmonary arterial hypertension in those with a widespread skin condition known as systemic sclerosis
- Heart problems due to lung disease, commonly known as cor pulmonale
- Blood clots in the lungs, a condition referred to as thromboembolic disease
- Cancer
- Sudden escape of air from the lungs into the chest cavity, known as spontaneous pneumothorax
Preventing Interstitial Pulmonary Fibrosis
Quitting smoking is crucial for improving your health, as well as avoiding contact with harmful natural and synthetic substances. If you have conditions that affect the ‘connective tissues’ (the materials that support and bind other tissues in the body), or other illnesses that affect your entire body, it’s important to get medical help.