Classically, UIP appears as peripheral, basilar disease with honeycombing. In NSIP, groundglass opacities predominate, with the potential for sub-pleural sparing.3
Vasculitis & the Lungs
“Vasculitic diseases with pulmonary involvement have a highly variable presentation, but a lot depends on the size of the vessel involved,” Dr. Guttentag explained.
Example: Capillary involvement causes alveolar hemorrhage, and small artery involvement causes nodules, masses or consolidations in anti-neutrophil cytoplasmic antibody (ANCA) associated vasculitis. In large vessel vasculitis, vessel stenosis and aneurysms are typical.4
Not All CTD Is Autoimmune
Dr. Guttentag took care to remind his audience that in patients with rheumatic disease and abnormal CT chest findings, we can’t forget about direct drug toxicity and opportunistic infections. “CTD itself isn’t always the culprit. Drug toxicity and infections may cause any IIP pattern, and clinical presentation may be acute or subacute,” he said.
Summary
Dr. Guttentag summarized take-home points in one slide. Many standard chest CTs are now thin section, so not all patients need a HRCT. But HRCT is essential for the initial evaluation of known or suspected ILD. Rheumatic diseases, drug toxicity and infection can have overlapping radiographic appearances because the lung can react to injury in only so many ways. Thus, keep your differential broad and integrate imaging findings with clinical history and laboratory data.
Samantha C. Shapiro, MD, is an academic rheumatologist and an affiliate faculty member of the Dell Medical School at the University of Texas at Austin. She received her training in internal medicine and rheumatology at Johns Hopkins University, Baltimore. She is also a member of the ACR Insurance Subcommittee.
References
- Webb WR, Muller NL, Naidich DP. High-Resolution CT of the Lung, 5th Edition. LWW; Fifth edition. 2014 Aug 19.
- Mira-Avendano I, Abril A, Burger CD, et al. Interstitial lung disease and other pulmonary manifestations in connective tissue diseases. Mayo Clin Proc. 2019 Feb;94(2):309–325.
- Travis WD, Costabel U, Hansell DM, et al. An official American Thoracic Society/European Respiratory Society statement: Update of the international multidisciplinary classification of the idiopathic interstitial pneumonias. Am J Respir Crit Care Med. 2013 Sep 15;188(6):733–748.
- Chung MP, Yi CA, Lee HY, et al. Imaging of pulmonary vasculitis. Radiology. 2010 May;255(2):322–341.
