MAUI, HAWAII – who develop shortness of breath and cough or a precipitous drop in their forced expiratory volume on pulmonary function testing, , said at the 2019 Rheumatology Winter Clinical Symposium.
“This is an underappreciated – and I think among the most potentially devastating – of the lung diseases we as rheumatologists will encounter in our patients,” said Dr. Fischer, a rheumatologist at the University of Colorado at Denver, Aurora, with a special interest in autoimmune lung disease.
“If you’re seeing patients with rheumatoid arthritis, SLE, or Sjögren’s and they’ve got bad asthma they can’t get under control, you’ve got to think about bronchiolitis because I can tell you your lung doc quite often is not thinking about this,” he added.
Bronchiolitis involves inflammation, narrowing, or obliteration of the small airways. The diagnosis is often missed because of the false sense of reassurance provided by the normal chest x-ray and regular CT findings, which are a feature of the disease.
“This is really important: You have to get a high-resolution CT that includes expiratory images, because that’s the only way you’re going to be able to tell if your patient has small airways disease,” he explained. “You must, must, must do an expiratory CT.”
A normal expiratory CT image should be gray, since the lungs are empty. Air is black on CT, so large areas of black intermixed with gray on an expiratory CT – a finding known as mosaicism – indicate air trapping due to small airways disease, Dr. Fischer noted.
Surgical lung biopsy will yield a pathologic report documenting isolated constrictive, follicular, and/or lymphocytic bronchiolitis. However, the terminology can be confusing: What pathologists describe as constrictive bronchiolitis is called obliterative by pulmonologists and radiologists.
Pulmonary function testing shows an obstructive defect. The diffusing capacity of the lungs for carbon monoxide (DLCO) is fairly normal, the forced expiratory volume in 1 second (FEV1) is sharply reduced, and the forced vital capacity (FVC) is near normal, with a resultant abnormally low FEV1/FVC ratio. A patient with bronchiolitis may or may not have a response to bronchodilators.
“I tell you, I’ve seen a bunch of these patients. They typically have a precipitous drop in their FEV1 and then stay stable at a very low level of lung function without much opportunity for improvement,” Dr. Fischer said. “Stability equals success in these patients. It’s really unusual to see much improvement.”
In theory, patients with follicular or lymphocytic bronchiolitis have an ongoing inflammatory process that should be amenable to rheumatologic ministrations. But there is no convincing evidence of treatment efficacy to date. And in obliterative bronchiolitis, marked by airway scarring, there is no reason to think anti-inflammatory therapies should be helpful. Anecdotally, Dr. Fischer said, he has seen immunosuppression help patients with obliterative bronchiolitis.
“Actually, the only proven therapy is lung transplantation,” he said.
He recommended that his fellow rheumatologists periodically use office spirometry to check the FEV1 in their patients with rheumatoid arthritis, Sjögren’s, or SLE, the forms of connective tissue disease most often associated with bronchiolitis. Compared with all the other testing rheumatologists routinely order in their patients, having them blow into a tube is a simple enough matter.
“We really don’t have anything to impact the natural history, but I like the notion of not being surprised. What are you going to do with that [abnormal] FEV1 data? I have no idea. But maybe it’s better to know earlier,” he said.
Dr. Fischer reported having no financial conflicts of interest regarding his presentation.