Interstitial Lung Disease and Its Causes

INTERSTITIAL LUNG DISEASE Prof .Dr: MUHAMMED WAHEEB AL,OBAIDY CONSULTANT CHEST PHYSCIAN MEDICAL COLLEGE UNIVERSITY Of BAGHDAD. MUHAMMED WAHEEB 2018

Objectives To know clear definition of disease. To cover important risk factors. Classification of diseases. Main way of clinical presentation. Approach to reach diagnosis of disease. Board line in disease management. Main complication of disease.

Definition A large group of disorders characterized by progressive scarring of the lung tissue between and supporting the air sacs. The scarring cause progressive lung stiffness Interstitial lung disease may be broadly categorized into known and unknown causes. Common known causes include autoimmune or rheumatologic diseases, occupational and organic exposures, medications, and radiation. Interstitial lung disease of unknown cause is predominated by idiopathic pulmonary fibrosis, a specific and progressive fibrotic lung disease, followed by the idiopathic interstitial pneumonias, such as nonspecific interstitial pneumonia (NSIP), and Sarcoidosis. Once lung scarring occurs, it's generally irreversible. Medications may slow the damage of interstitial lung disease, Lung transplant is an option for some people who have worsening interstitial lung disease despite treatment.

Causes Interstitial lung disease may occur when an injury lungs triggers an abnormal healing response. Interstitial lung disease can be triggered by many things including autoimmune diseases, exposure to organic and inorganic agents in the home or workplace, medications, and some types of radiation. In some cases, the cause is unknown.

Occupational and environmental factors Long-term exposure to a number of organic and inorganic materials and agents can damage your lungs. These include: Asbestos fibers Bird protein (live pets and feather-containing products) Coal dust Grain dust Mold from indoor hot tubs, showers and prior water damage Silica dust

Breathing in dust or other particles in the air is responsible for some types of interstitial lung diseases. Specific types include : Black lung disease among coal miners, from inhaling coal dust. Farmer's lung, from inhaling farm dust. Asbestosis, from inhaling asbestos fibers. Siderosis, from inhaling iron from mines or welding fumes. Silicosis, from inhaling silica dust.

Medications Many drugs can damage lungs, especially: Chemotherapy/immunomodulating drugs, such as methotrexate and cyclophosphamide. Heart medications, such as amiodarone (Cordarone, Nexterone, Pacerone) and propranolol (Inderal, Inderide, Innopran). Some antibiotics, such as nitrofurantoin (Macrobid, Macrodantin, others) and sulfasalazine (Azulfidine).

Radiation Some people who have radiation therapy for lung or breast cancer show signs of lung damage months or sometimes years after the initial treatment. The severity of the damage depends on: How much of the lung was exposed to radiation. The total amount of radiation administered. Whether chemotherapy was also used. The presence of underlying lung disease.

Medical conditions Lung damage can be associated with the following autoimmune diseases: Dermatomyositis/polymyositis Mixed-connective tissue disease Pulmonary vasculitis (microscopic polyangiitis) Rheumatoid arthritis Sarcoidosis Scleroderma Sjogren's syndrome Systemic lupus erythematosus Undifferentiated connective tissue disease

Risk factors Factors that may make you more susceptible to interstitial lung disease include: Age. More likely to affect adults, although infants and children are sometimes affected. Exposure to occupational and environmental toxins. work in mining, farming or construction or for any reason are exposed to environmental agents known to damage lungs. Family history. There is evidence that some forms of interstitial lung disease are heritable and risk of developing it is increased if close family members have the disease.

Risk factors Radiation/chemotherapy/immunomodulator drugs: Smoking. Some forms of interstitial lung disease are more likely to occur in people with a history of smoking, and active smoking may make the condition worse, especially if there is associated emphysema.

Symptoms The primary signs and symptoms of interstitial lung disease include: Dry cough Shortness of breath at rest or with exertion. By the time symptoms appear, irreversible lung damage may have already occurred.

Diagnosis Identifying and determining the cause of interstitial lung disease can be challenging. 1-Imaging tests A-Chest X-ray. . Occasionally, the chest X-ray is normal and further tests are required to explain shortness of breath. In some diseases (Sarcoidosis), chest X- rays may also be used to track the progression of disease

Diagnosis B-Computerized tomography (CT) scan. A high-resolution CT scan can be particularly helpful in determining the extent of lung damage caused by interstitial lung disease. It can reveal details and patterns of fibrosis. C-Echocardiogram. This test can be used to assess abnormal pressures in the right and left sides heart.

Diagnosis 2-Pulmonary function tests : A- PulseOximetry. To measure the oxygen saturation in blood during and while walking. If there is concern about low oxygen levels during sleep, the test can be performed overnight. B-Spirometry and diffusion capacity. It also measures how easily oxygen can move from the lungs into the bloodstream.

Diagnosis 3-Lung tissue analysis The tissue sample may be obtained in one of these ways: A-Bronchoscopic biopsy. The serious risks of bronchoscopic biopsy include bleeding or a deflated lung. B-Open lung biopsy. It's often the only way to obtain a large enough tissue sample to make an accurate diagnosis. During the procedure under general anesthesia, surgical instruments and a small camera are inserted through two or three small incisions between ribs. The camera allows surgeon to view lungs on a video monitor while removing tissue samples from lungs.

Treatments and drugs The lung scarring that occurs in interstitial lung disease is often irreversible. Treatment will not always be effective in stopping the ultimate progression of the disease. Some treatments may improve symptoms temporarily or slow disease progress. Because many of the different types of scarring disorders have no approved or proven therapies, clinical studies may be an option to receive an experimental treatment

Treatment 1- Avoid offending agent: If there is a known exposure, avoiding the inciting agent is a first step to treatment 2-Medications Depending on the underlying cause of interstitial lung disease, treatments fall into two categories: A-Anti-inflammatories: Interstitial lung disease that has a known inflammatory or autoimmune process may benefit from initial anti-inflammatory or immunosuppressing medications. B- Anti-fibrotics. Specifically for idiopathic pulmonary fibrosis, there are two medications now available for slowing the scarring process.

PIRFENIDONE. Pirfenidone (1800 mg/day for 1 year) (5-methyl-1-phenyl-2-[1H]- pyridone) is a novel anti-fibrotic and anti-inflammatory agent that inhibits the progression of fibrosis in animal models. It reduced disease progression as reflected by better lung volume (decreases the rate of decline in forced vital capacity) , improved exercise tolerance, and better progression-free survival.

Nintedanib (50mg /d up to 150 mg twice daily). - No significant difference between groups are seen in mortality. - The percentage of patients with more than 10% FVC decline during 1 year follow-up period are lower with the highest dose. - It decrease (in any dose) the risk of IPF acute exacerbations compared with controls

Treatment 3-Oxygen therapy Using oxygen can't stop lung damage, but it can: A-make breathing and exercise easier. B-Prevent or lessen complications from low blood oxygen levels. C-Reduce blood pressure in the right side heart. D-Improve sleep and sense of well-being.

Treatment 4-Surgery Lung transplantation may be an option of last resort for people with severe interstitial lung disease who haven't benefited from other treatment options.

5-Vaccinations and Infection Avoidance Because many ILD patients are treated with immunosuppressive medications and are at some modest increased risk for the development of infections, Patients with ILD should receive a pneumococcal and a yearly influenza virus vaccine. Additionally, we recommend that patients practice good hand hygiene (e.g., frequent hand washing). We do not recommend the use of masks or special antibacterial products. Patients treated with certain specific immunosuppressive regimens should receive Pneumocystis prophylaxis..

6-Pulmonary Rehabilitation and Exercise Therapy: pulmonary rehabilitation in the management of ILD has not been as well studied as it has in obstructive lung disease. Pulmonary rehabilitation is important in building aerobic fitness, maintaining physical activity, and improving quality of life. We encourage all of our patients to enroll in outpatient pulmonary rehabilitation and to continue maintenance therapy.

Complications Interstitial lung disease can lead to a series of life- threatening complications, including: Acute exacerbation. Acute exacerbation is a rapid worsening of respiratory function, increased lung infiltrates seen on x-Rays and shortness of breath that are not caused by other definable processes such as congestive heart failure, blood clots in the lung or infection. Gastroesophageal reflux disease (GERD). Recent studies suggest that GERD is associated with a more rapid progression of idiopathic pulmonary fibrosis.

complication pulmonary hypertension: It begins when scar tissue or low oxygen levels restrict the smallest blood vessels, limiting blood flow through the lungs. leading to failure or dysfunction of the right side of the heart (cor pulmonale). Low oxygen (hypoxemia). As lung disease progresses, oxygen support may be required both at rest and with exertion. Respiratory failure. In the end stage of chronic interstitial lung disease, respiratory failure occurs when severely low blood oxygen levels along with rising pressures in the pulmonary arteries and the right ventricle cause heart failure.

Conclusion The entities grouped as ILDs are a diverse group of illnesses of varied causation, treatment, and prognosis. In general, these diseases manifest as chronic, progressive dyspnea on exertion and cough. Findings on examination are often limited to the chest in the form of fine inspiratory crackles. The most common chest radiograph finding is diffuse reticular or reticulonodular infiltrates with reduced lung volumes. Pulmonary function testing usually reveals restrictive physiology and decreased diffusion capacity; however, other patterns can be seen. Therapy depends on the underlying disease and may consist of immunosuppressive drugs and avoidance of disease- inducing exposures.

Summary Chronic nonmalignant pain (CNMP) is our leading cause of disability. The interstitial lung diseases are a diverse group of disorders organized by cause. A careful history, paying attention to exposures and systemic diseases, is required to arrive at a correct diagnosis. High-resolution computed tomography scanning and pulmonary function testing are integral to diagnosing and monitoring disease progression. Treatment depends entirely on the disease cause and may include observation, exposure avoidance, or immunosuppression.

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