Dr. Dinesh Khanna, (Professor of Medicine at University of Michigan, USA.), spoke about Interstitial Lung Disease (ILD) and its treatment in scleroderma at the 2024 Sclerocon conference organized by Scleroderma India.
Dr. Khanna highlighted that lung fibrosis affects 60% to 70% of scleroderma patients and emphasized the importance of early diagnosis and timely treatment. He also discussed the role of autoantibodies, the necessity of immunizations and shed light on ongoing clinical trials for advanced treatments.
Effect of lung fibrosis on lung function
The lungs are essential for breathing and oxygenating the blood. We have two lungs: the right lung with three lobes – upper, middle, lower, and the left lung with two lobes – upper and lower. When we breathe, air travels through the trachea into the lungs, and reaches to alveoli. Those are surrounded by capillaries, allowing oxygen to diffuse into the blood and carbon dioxide to be exhaled.
About 60% to 70% of individuals with scleroderma develop by lung fibrosis. This condition impairs the normal process of oxygen exchange in the lungs due to damage and scarring of the alveoli and capillaries. This leads to a reduced oxygen supply and compromised lung function.
Why do we worry about lung involvement in scleroderma?
The two leading causes of death in people with scleroderma are pulmonary fibrosis (lung fibrosis) and pulmonary arterial hypertension. Studies have stated that pulmonary fibrosis and hypertension are the main causes of mortality in scleroderma patients. At the University of Michigan where I practice, these conditions continue to be the leading cause of death. Systemic sclerosis associated interstitial lung disease (SSc-ILD) affects approximately 70% of patients leading to reduced lung function and severe complications.
Diagnosis of lung fibrosis
It involves a combination of symptoms assessment, Pulmonary Function Tests (PFT), and CT scans. Doctors often conduct blood tests to identify autoantibodies as they are predictive of progressive ILD. Autoantibodies are antibodies produced against proteins that are normally present but can be targeted in autoimmune diseases. For scleroderma, also known as systemic sclerosis, a common autoantibody is the anti-nuclear antibody, which is present in about 95% of the patients. There are also other scleroderma specific autoantibodies such as;
- Anti-centromere antibody – lower risk of severe lung fibrosis; more common in India.
- Anti-topoisomerase I antibody – high risk of severe lung fibrosis.
- Anti RNA polymerase III antibody – medium risk of lung fibrosis; it is less common in India.
- Anti fibrillarin antibody – medium risk of lung fibrosis.
- Anti Pm-Scl antibody – low to medium risk of lung fibrosis.
Pulmonary Function Test (PFT) measures lung volume and diffusion capacity, providing detailed information on lung function. This test is usually done by Pulmonologist and takes 30-90 minutes. Normal lung function can range between 8-120%. PFTs can be normal in 25% of patients with ILD. It can be abnormal due to poor fit of mouthpiece or muscle weakness. Hence there are some challenges associated with this test.
CT scans are gold standard for detecting lung fibrosis, even when PFTs are normal. But sometimes patients or doctors do not do CT of the chest because of the risk of radiation. Radiation exposure from a CT scan is about 2 to 4 mSv, which is comparable to the annual natural background radiation in the US. This level is much lower than the occupational exposure limit of 50 mSv per year for radiology technicians. It is generally safe to have one or two CT scans over a life time for better diagnosis for scleroderma patients.
Shortness of breath and chronic cough may indicate lung fibrosis in patient. Shortness of breath can also result from other conditions such as pulmonary hypertension, heart involvement or gastric reflux. Hence, it is crucial to consult your Rheumatologist and Pulmonologist for early diagnosis without delay.
Ongoing clinical trials for lung fibrosis
Currently we are conducting an international clinical trial called CONQUEST, which includes 400 scleroderma patients from India. This trial aims to evaluate two novel therapies for lung fibrosis in scleroderma patients. The goal is to preserve lung function and improve the quality of life for the patients. It is a good opportunity to bring advanced treatments to a broader population, including those in India.
Treatment and management for lung fibrosis in scleroderma patients
It includes a combination of health education, oxygen therapy, immunization, and pharmacological interventions. Understanding lung fibrosis and what actions to take for managing this condition is crucial. Patient must get flu, pneumonia, COVID-19 and shingles vaccines before initiation of immunosuppressive therapy.
Immunosuppressive therapies like mycophenolate and rituximab, and antifibrotic therapies such as nintedanib and pirfenidone, are commonly used. Stem cell transplantation or lung transplantation may be considered for advanced cases.
Any scarring, whether in the skin, kidney, gut, heart, liver or lung is irreversible. Hence, it is advised not to wait for symptoms to occur, as this can worsen the disease. Keep consulting your rheumatologist or pulmonologist for regular examinations.
Managing acid refluxes to prevent aspiration into the lungs is critical as it can lead to lung inflammation. Patients should sleep at an angle by elevating the head of the bed with bricks, not just extra pillows, and use proton pump inhibitors as prescribed by their doctors.
Early detection can help preserve lung function and prevent irreversible damage. Do not wait for symptoms to appear before seeking medical care. Effective management of heart and lung health is essential for maintaining quality of life.
Dr. Dinesh Khanna ( M.D.,M.S.)
Frederick G.L.Huetwell Professor of Rheumatology, Professor of Medicine, University of Michigan
Over 30 years of experience, particularly in lung complications of scleroderma,
Twitter : @sclerodermaUM
Note : This is a loosely edited text of the presentation made by Dr. Khanna at the Sclerocon 2024 Conference - https://www.youtube.com/watch?v=0GoVfFIb83w
