Interstitial Lung Disease (ILD) and Prevalence in Sjögren’s
Interstitial lung disease (ILD) refers to a broad group of disorders that can cause inflammation and/or scarring in the lungs. Over time, this can progress to cause symptoms such as shortness of breath and chronic cough, pose limitations in daily life, and in severe cases be life threatening. Many different insults such as environmental exposures, viral infections etc. can lead to the development of ILD, including autoimmune diseases such as Sjögren’s disease. In fact, ILD can be seen in about 10-15% of patients with Sjögren’s.
ILD Symptoms in Sjögren’s
The most common symptoms from ILD include shortness of breath and cough; however, early in the disease course patients may be relatively asymptomatic. This is one of the reasons behind the recommendation to actively screen for lung involvement in patients with Sjögren’s in the recently published Guidelines for Pulmonary involvement in Sjögren’s. It is also worth noting that ILD may be the presenting manifestation of Sjögren’s disease. Thus, it is important to ask about symptoms that might clue towards the possibility of underlying Sjögren’s disease (or other autoimmune diseases) when evaluating patients with ILD.
Diagnosis of ILD
The best non-invasive way to look for ILD is via chest CT scan. Chest CT can not only help answer whether there is ILD but can also provide useful information regarding the type and severity of ILD. Patients with Sjögren’s, especially those with pulmonary symptoms such as shortness of breath and/or cough that lasts beyond a few weeks, should have a low threshold to obtain chest imaging. Lung biopsy is generally not needed in patients with underlying Sjögren’s; however, may be required in some instances on a case-by-case basis depending upon the underlying features and individual circumstances.
Complications of ILD in Sjögren’s Patients
In addition to the inflammation and scarring typically seen in all ILDs, patients with Sjögren’s tend to develop a unique form of lung involvement where air gets trapped within the lungs and causes the formation of multiple air-filled pockets, known as cysts. These cysts might make patients with Sjögren’s more likely to experience sudden onset lung collapse, also known as pneumothorax. As such, it is important for patients with Sjögren’s to be aware of the most common symptoms of a pneumothorax - sudden onset shortness of breath and chest pain that is worsened by deep breathing. The development of these symptoms should prompt patients with Sjögren’s to seek immediate medical attention.
Treatment of ILD
Patients with ILD require long-term monitoring to better understand the disease trajectory and to help make treatment decisions. This goal is typically accomplished by performing serial pulmonary function tests (PFTs). Patients with minimal symptoms and normal to mildly affected PFTs, especially those with stable PFTs over time, may not require any specific treatment beyond supportive care. On the other hand, patients with significant symptoms and/or moderate-severe derangement in PFTs or progressive disease often require treatment for their ILD. General modalities for treatment include immunosuppressive therapies with consideration of antifibrotics in patients who progress despite adequate immune suppression. Detailed description and suggested algorithms for the management of ILD in patients with Sjögren’s is available here.