Role of Lung Ultrasound in Screening for Interstitial Lung Disease in Patients With Rheumatoid Arthritis

Interstitial lung disease (ILD) is a common complication of connective tissue disease (CTD) and a leading cause of morbidity and mortality. Thus, early diagnosis and treatment may improve the prognosis of patients with ILD.

High-resolution computed tomography (HRCT) is the gold standard for ILD diagnosis. It can detect the location and type of lesions through its high resolution. Unfortunately, it is hampered by high cost and potential risks associated with radiation exposure, especially for pregnant women.

Accordingly, finding a low-cost, non-invasive, and non-ionizing diagnostic method is necessary for ILD. Lung ultrasound (LUS) has all of these advantages and is an accessible bedside procedure. As a result, it is easily accepted by patients. Over the last 20 years, LUS has mainly been applied in CTD-ILD diagnosis, where it has shown high sensitivity and specificity. The assessment of ILD by LUS is determined by the number of B-lines, which appear as a comet tail signal and originate from the pleural line without fading to the edge of the screen.

The total number of B-lines was found to correlate well with the HRCT score. To assess the number of B-lines, previous studies used various scoring systems by designing different intercostal spaces (LIS), such as 72 LIS, 50 LIS, and 14 LIS. This study aims to assess Lung ultrasound as a screening tool for early interstitial lung disease in connective tissue disease patients.

Inclusion criteria

• Confirmed diagnosis of rheumatoid arthritis and suspicion of interstitial lung disease on history and/ or clinical examination, age > 18 years

Exclusion criteria

• Patients who refuse to participate in the study,
• Patients with a history of pulmonary neoplasia or
• Patients with causes of interstitial fluid, such as, heart failure, diastolic dysfunction, asthma or pulmonary edema.