Risk Factors for Interstitial Lung Disease

What Is Interstitial Lung Disease?

The term "interstitial lung disease" is a generalized term used to describe a broad range of diseases that result in inflammation and fibrosis (scarring) of the lung tissues. It is a heterogeneous group of disorders that can be classified based on common histopathology, radiological findings, and clinical parameters. Interstitial lung disease, or ILD, is a diffused parenchymal disease. Scarring makes the lungs stiff, which makes it challenging to breathe and deliver oxygen to the blood. Interstitial lung disease-related lung damage is frequently permanent and worsens over time. Interstitial lung disease can affect anyone, even young children. ILDs can be caused by a variety of factors, including genetics, particular drugs, asbestos exposure, and medical procedures like radiation or chemotherapy.

What Are Some Examples of the Interstitial Lung Disease?

There are more than 200 interstitial lung diseases. Some of the common interstitial lung diseases are:

• Idiopathic pulmonary fibrosis (most common).

• Asbestosis.

• Silicosis.

• Radiation pneumonitis.

• Nonspecific interstitial pneumonia.

Are Interstitial Lung Diseases Common?

Estimating the incidence rates of interstitial lung disease in the United States has been challenging. Many people believe that the frequency is much more than previously assumed. The failure to diagnose the condition may be the cause of the reported occurrence being so low.

• The estimated incidence rate is 30 patients per 100,000 individuals every year.

• In general, there are 80.9 cases per 100,000 males and 67.2 cases per 100,000 females each year.

What Causes Interstitial Lung Disease?

Common causes of interstitial lung disease include the following:

• Environmental and Occupational Exposure: The lungs can get damaged from prolonged exposure to environmental or occupational contaminants. Toxins in gases, chemical dust, and mineral dust are common agents that can cause interstitial lung diseases like silicosis, asbestosis, etc. There are associations between various types of mineral dust, but silica, asbestos, dust from a coal mine, and beryllium are the most commonly known to cause interstitial lung disease.

• Autoimmune Diseases: Several rheumatic and autoimmune diseases affect almost all parts of the lungs and result in interstitial lung diseases.

• Drug-Induced: About 350 medications have been found to contribute to pulmonary problems, either directly or indirectly via reactive metabolites or as a part of a broader reaction.

• Idiopathic: This is the most common cause of interstitial lung diseases. Unlike infectious pneumonia, this main type is known as idiopathic interstitial pneumonia and causes inflammation and lung fibrosis. There are seven main varieties, each with distinct histological characteristics and clinical differences. The majority of instances are random, but genetics may be involved.

What Are the Risk Factors for Interstitial Lung Disease?

Interstitial lung diseases may occur due to the above-mentioned causes. However, certain risk factors increase the chances of developing interstitial lung disease in an individual. These risk factors are as follows:

• Age: Advanced or old age is a well-established risk factor for ILD. Individuals over the age of 70 are at the highest risk.

• Gender: Men are more susceptible to ILD as compared to women.

• Smoking: Smoking cigarettes, vapes, e-cigarettes, hookah, etc., increases the risk of ILD in an individual because smoking damages the lungs.

• Certain Medical Conditions: A person is more likely to acquire ILD if they have a history of specific diseases or conditions, such as hepatitis C virus infection, TB (tuberculosis), pneumonia, chronic obstructive pulmonary disease (COPD), or connective tissue disease.

• Occupation: An individual regularly exposed to harmful substances like silica and asbestos at work is also at a high risk of developing ILD.

• Radiation Exposure: An individual who has undergone radiation therapy for the chest or has been exposed to radiation is also at high risk for developing ILD.

What Are the Symptoms of Interstitial Lung Disease?

Symptoms of interstitial lung disease include:

• Dyspnea or shortness of breath due to damaged lungs is the most common symptom.

• Chest discomfort.

• Cough (dry).

• Tiredness and fatigue.

• Specific symptoms depend on the cause of interstitial lung disease.

• Pleuritic chest pain.

• Hemoptysis (spitting blood from lungs).

• Some patients may exhibit atypical imaging while being fully asymptomatic.

• Patients with severe illness may have physical symptoms of pulmonary hypertension and digital clubbing.

How Is Interstitial Lung Disease Diagnosed?

It might be difficult to identify and pinpoint the etiology of interstitial lung disease because this broad category includes a lot of diseases. Additionally, various medical disorder’s signs and symptoms can resemble those of interstitial lung disease; therefore, before reaching a final diagnosis, clinicians must rule out other similar diseases.

• Blood Examinations: Proteins, antibodies, and other indicators of autoimmune conditions or inflammatory responses to environmental factors can be detected in some blood examinations.

• CT (Computerized Tomography) Scan: CT scans are the gold standard for diagnosing interstitial lung disease. In a CT scan, X-ray pictures captured from numerous angles are combined by a computer to create cross-sectional views of the organ (lungs). A high-resolution CT scan can assess the level of lung injury caused by ILD (interstitial lung disease). It may provide information about fibrosis that helps in diagnosing the condition and determining the best course of treatment.

• Echocardiogram: An echocardiogram, a heart sonogram, employs sound waves to view the heart. It can create still pictures of the internal anatomy of the heart and videos of the heart.

• Spirometry: During this test, the patient must perform a rapid and forceful exhalation through a tube attached to a device that monitors how much air they can hold in their lungs and how fast they can expel it. Additionally, this test gauges how efficiently oxygen can enter the blood from the lungs.

• Oximetry: In this easy test, the blood's oxygen saturation is measured using a tiny device placed on one of the patient's fingers.

• Bronchoscopy: During this treatment, the doctor uses a tiny, flexible tube (bronchoscope) inserted via mouth or nose into the lungs to retrieve extremely small tissue samples; typically, the sample is the size of a pinhead. The sample is then sent to the laboratory for analysis.

• Bronchoalveolar Lavage: During this treatment, the doctor uses a bronchoscope to inject around a tablespoon of salt water into a lung, which is quickly suctioned out. Cells from air sacs are present in the solution that is extracted.

• Surgical Biopsy: A tissue sample is surgically collected and sent to the laboratory for analysis during this procedure. Even though biopsy is a more invasive technique with risks, it is frequently the only method to get a big enough sample of tissue to establish a precise diagnosis.

How Is Interstitial Lung Disease Treated?

There is no specific treatment for interstitial lung disease. ILD treatment often focuses on addressing the underlying condition and reducing symptoms. Interstitial lung disease causes lung scarring that cannot be reversed, and treatment may not always successfully stop the condition's eventual progression. Some therapies may momentarily reduce symptoms or prevent the spread of the disease. Other treatment modalities may support enhancing the quality of life.

1. Medications:

• Corticosteroids: Prednisone is a corticosteroid frequently used in conjunction with other immune-suppressing medications to treat interstitial lung diseases.

• Medications for Idiopathic Pulmonary Fibrosis: Pirfenidone and Nintedanib have been shown to halt the course of some interstitial lung diseases.

2. Oxygen Therapy: Oxygen therapy cannot reverse the damage or scarring of the lungs, but it can help in breathing easily, prevent complications due to reduced blood oxygen saturation, reduce blood pressure, and improve other symptoms.

3. Rehabilitation: The goal of pulmonary rehabilitation is to assist persons with interstitial lung disease to live healthy, fulfilling lives and improve everyday functionality. Pulmonary rehabilitation focuses on the following:

• Lung exercises to improve stamina and endurance.

• Improving lung efficiency with different breathing techniques.

• Nutritional monitoring.

• Psychological and emotional support.

4. Surgery: For some individuals with advanced interstitial lung disease who have not responded well to conventional treatments, lung transplantation may be their final resort.

Conclusion:

Living with interstitial lung diseases can be mentally and physically challenging on everyday levels. There are several risk factors associated with the development of interstitial lung diseases. These risk factors increase the chances of developing interstitial lung disease and can worsen the condition's symptoms and prognosis. Different interstitial lung disease subgroups have different prognoses. Acute eosinophilic pneumonia, cellular interstitial pneumonia, lymphocytic interstitial pneumonitis, granulomatous interstitial pneumonitis, alveolar proteinosis, etc., are common sub-classes that respond to treatment. Advanced diseases like idiopathic pulmonary fibrosis are examples of subtypes that are extremely resistant to treatment. In any scenario, the prognosis still corresponds to how severe the symptoms were when it was first diagnosed.