ILD on the Rise, Doctors Offer Tips for Diagnosing Deadly Disease

Thomas R. Collins

September 14, 2022

Too often, when patients come to see Tejaswini Kulkarni, MD, with shortness of breath and cough and are diagnosed with interstitial lung disease (ILD), they are past the point when treatments would most benefit them.

"There is definitely a delay from the time of symptom onset to the time that they are even evaluated for ILD," said Kulkarni of the department of pulmonary, allergy and critical care medicine at the University of Alabama, Birmingham. "Some patients have had a significant loss of lung function by the time they come to see us. By that point we are limited by what treatment options we can offer."

Interstitial lung disease is an umbrella term for a group of disorders involving progressive scarring of the lungs – typically irreversible – usually caused by long-term exposure to hazardous materials or by autoimmune effects. It includes idiopathic pulmonary fibrosis (IPF), a disease that is fairly rare but which has therapy options that can be effective if caught early enough. The term pulmonary fibrosis refers to lung scarring. Another type of ILD is pulmonary sarcoidosis, in which small clumps of immune cells form in the lungs in an immune response sometimes following an environmental trigger, and can lead to lung scarring if it doesn't resolve.

Cases of ILD appears to be on the rise, and COVID-19 has made diagnosing it more complicated. One study found the prevalence of ILD and pulmonary sarcoidosis in high-income countries was about 122 of every 100,000 people in 1990 and rose to about 198 of every 100,000 people in 2017. The data were pulled from the Global Burden of Diseases, Injuries, and Risk Factors Study 2017. Globally, the researchers found a prevalence of 62 per 100,000 in 1990, compared with 82 per 100,000 in 2017.

If all of a patient's symptoms have appeared post COVID and a physician is seeing a patient within 4-6 weeks of COVID symptoms, it is likely that the symptoms are COVID related. But a full work-up is recommended if a patient has lung crackles, which are an indicator of lung scarring, she said.

"The patterns that are seen on CT scan for COVID pneumonia are very distinct from what we expect to see with idiopathic pulmonary fibrosis," Kulkarni said. "Putting all this information together is what is important to differentiate it from COVID pneumonia, as well as other types of ILD."

A study published earlier this year found similarities between COVID-19 and IPF in gene expression, their IL-15-heavy cytokine storms, and the type of damage to alveolar cells. Both might be driven by endoplasmic reticulum stress, they found.

"COVID-19 resembles IPF at a fundamental level," they wrote.

Jeffrey Horowitz, MD, a pulmonologist and professor of medicine at the Ohio State University, said the need for early diagnosis is in part a function of the therapies available for ILD.

"They don't make the lung function better," he said. "So delays in diagnosis mean that there's the possibility of underlying progression for months, or sometimes years, before the diagnosis is recognized."

In an area in which diagnosis is delayed and the prognosis is dire – 3-5 years in untreated patients after diagnosis – "there's a tremendous amount of nihilism out there" among patients, he said.

He said patients with long-term shortness of breath and unexplained cough are often told they have asthma and are prescribed inhalers, but then further assessment isn't performed when those don't work.

Diagnosing ILD in Primary Care

Many primary care physicians feel ill-equipped to discuss IPF. More than a dozen physicians contacted for this piece to talk about ILD either did not respond, or said they felt unqualified to respond to questions on the disease.

"Not my area of expertise" and "I don't think I'm the right person for this discussion" were two of the responses provided to this news organization.

"For some reason, in the world of primary care, it seems like there's an impediment to getting pulmonary function studies," Horowitz said. "Anybody who has a persistent ongoing prolonged unexplained shortness of breath and cough should have pulmonary function studies done."

Listening to the lungs alone might not be enough, he said. There might be no clear sign in the case of early pulmonary fibrosis, he said.

"There's the textbook description of these Velcro-sounding crackles, but sometimes it's very subtle," he said. "And unless you're listening very carefully it can easily be missed by somebody who has a busy practice, or it's loud."

William E. Golden, MD, professor of medicine and public health at the University of Arkansas, Little Rock, is the sole primary care physician contacted for this piece who spoke with authority on ILD.

For cases of suspected ILD, internist Golden, who also serves on the editorial advisory board of Internal Medicine News, suggested ordering a test for diffusing capacity for carbon monoxide (DLCO), which will be low in the case of IPF, along with a fine-cut lung CT scan to assess ongoing fibrotic changes.

It's "not that difficult, but you need to have an index of suspicion for the diagnosis," he said.

New Initiative for Helping Diagnose ILD

Kulkarni is a committee member for a new effort under way to try to get patients with ILD diagnosed earlier.

The initiative, called Bridging Specialties: Timely Diagnosis for ILD Patients, has already produced an introductory podcast and a white paper on the effort, and its rationale is expected to be released soon, according to Kulkarni and her fellow committee members.

The American College of Chest Physicians and the Three Lakes Foundation – a foundation dedicated to pulmonary fibrosis awareness and research – are working together on this initiative. They plan to put together a suite of resources, to be gradually rolled out on the college's website, to raise awareness about the importance of early diagnosis of ILD.

The full toolkit, expected to be rolled out over the next 12 months, will include a series of podcasts and resources on how to get patients diagnosed earlier and steps to take in cases of suspected ILD, Kulkarni said.

"The goal would be to try to increase awareness about the disease so that people start thinking more about it up front – and not after we've ruled out everything else," she said. The main audience will be primary care providers, but patients and community pulmonologists would likely also benefit from the resources, the committee members said.

The urgency of the initiative stems from the way ILD treatments work. They are antifibrotic, meaning they help prevent scar tissue from forming, but they can't reverse scar tissue that has already formed. If scarring is severe, the only option might be a lung transplant, and, since the average age at ILD diagnosis is in the 60s, many patients have comorbidities that make them ineligible for transplant. According to the Global Burden of Disease Study mentioned earlier, the death rate per 100,000 people with ILD was 1.93 in 2017.

"The longer we take to diagnose it, the more chance that inflammation will become scar tissue," Kularni explained.

William Lago, MD, another member of the committee and a family physician, said identifying ILD early is not a straightforward matter .

"When they first present, it's hard to pick up," said Lago, who is also a staff physician at Cleveland Clinic's Wooster Family Health Center and medical director of the COVID Recover Clinic there. "Many of them, even themselves, will discount the symptoms."

Lago said that patients might resist having a work-up even when a primary care physician identifies symptoms as possible ILD. In rural settings, they might have to travel quite a distance for a CT scan or other necessary evaluations, or they might just not think the symptoms are serious enough.

"Most of the time when I've picked up some of my pulmonary fibrosis patients, it's been incidentally while they're in the office for other things," he said. He often has to "push the issue" for further work-up, he said.

The overlap of shortness of breath and cough with other, much more common disorders, such as heart disease or chronic obstructive pulmonary disease (COPD), make ILD diagnosis a challenge, he said.

"For most of us, we've got sometimes 10 or 15 minutes with a patient who's presenting with 5-6 different problems. And the shortness of breath or the occasional cough – that they think is nothing – is probably the least of those," Lago said.

Golden said he suspected a tool like the one being developed by CHEST to be useful for some and not useful for others. He added that "no one has the time to spend on that kind of thing."

Instead, he suggested just reinforcing what the core symptoms are and what the core testing is, "to make people think about it."

Horowitiz seemed more optimistic about the likelihood of the CHEST tool being utilized to diagnose ILD.

Whether and how he would use the CHEST resource will depend on the final form it takes, Horowitz said. It's encouraging that it's being put together by a credible source, he added.

Kulkarni reported financial relationships with Boehringer Ingelheim, Aluda Pharmaceuticals and PureTech Lyt-100 Inc. Lago, Horowitz, and Golden reported no relevant disclosures.

Katie Lennon contributed to this report.

This article originally appeared on MDedge.com, part of the Medscape Professional Network.

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