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Identifying Idiopathic Subglottic Stenosis: Signs & Symptoms

Author Julia Casazza covers Identifying Idiopathic Subglottic Stenosis: Signs & Symptoms on BackTable ENT

Julia Casazza • Updated Aug 16, 2024 • 49 hits

Dyspnea, abundant mucus, plus non-response to asthma and reflux medications? Idiopathic subglottic stenosis symptoms could be the culprit. While ISS is rare, the progressive airway stenosis that patients experience can be fatal. Expert laryngologist Dr. Stephen Schoeff recently shared thoughts on idiopathic subglottic stenosis causes, diagnosis and management with the BackTable ENT Podcast.

This article features excerpts from the BackTable ENT Podcast. We’ve provided the highlight reel in this article, and you can listen to the full podcast below.

The BackTable ENT Brief

• Nearly all patients affected by idiopathic subglottic stenosis are women in their twenties to seventies. Men comprise fewer than 5% of those affected, largely due to their greater airway diameter.

• Idiopathic subglottic stenosis symptoms will present with complaints of slowly-progressive exercise intolerance and a constant need to clear their throat.

• Idiopathic subglottic stenosis shares symptoms with laryngopharyngeal reflux (LPR), airway manifestations of granulomatosis with polyangiitis (GPA), paradoxical vocal fold motion (PVFM), and pulmonary disease. Presence or absence of associated symptoms and serologies aid in diagnosis.

• Labs are not useful for diagnosing idiopathic subglottic stenosis itself, but can help confirm or eliminate competing diagnoses. History and physical with bronchoscopy is sufficient to diagnose most cases.

• Idiopathic subglottic stenosis has a distinct “spiraling” scar pattern visible on endoscopic examination.

Identifying Idiopathic Subglottic Stenosis: Signs & Symptoms

Table of Contents

(1) Initial Idiopathic Subglottic Stenosis Symtpoms

(2) History-Taking with Idiopathic Subglottic Stenosis in Mind

(3) Physical Exam Findings in Idiopathic Subglottic Stenosis

(4) Labs & Imaging for Idiopathic Subglottic Stenosis

Initial Idiopathic Subglottic Stenosis Symtpoms

Idiopathic subglottic stenosis symptoms present as a slow-onset stridor accompanied by increased mucus. Patients may report previous (ineffective) treatment with antacids or asthma meds. Patients may also report an incessant need to clear their throat. This constant throat-clearing is caused by mucus buildup in the stenosed, inflamed airway. Demographically, almost all patients with ISS are women in their third to eighth decades of life; men are far less likely to develop idiopathic subglottic stenosis due to their wider airways.

[Dr. Stephen Schoeff]
That's a great question. At some level, it's an all the above sort of answer, but idiopathic patients really do tend to present a little differently than some of the other causes of subglottic stenosis. The classic subglottic stenosis that most non-laryngologists think about is going to be more of your traumatic or iatrogenic subglottic stenosis. You're likely to encounter that patient in the hospital. They've been intubated for a while, or they've had a tracheostomy and then they have an A-frame deformity. A lot of times they're going to be in these higher acuity settings and a more rapid onset of symptoms or persistence of symptoms. Whereas, the idiopathic patients tend to get shuffled around quite a bit. They often are otherwise pretty healthy. They're showing up with some mild stridor, potentially, but often not even stridor at their first presentation to someone where they're presenting, say, to their primary care provider with increasing mucus in the throat, which we all know is a super common complaint, or increased cough, maybe slightly shorter breath, but pretty gradual, pretty slow onset. That's part of what makes it such a challenging condition is that they oftentimes get managed with some OTC meds, or maybe acid reflux meds, and albuterol inhaler and they're not getting better. Oftentimes, they'll end up actually getting sent over to allergy or pulmonology first. Then finally, the stridor becomes more noticeable. That's oftentimes when they may either end up in an urgent care or emergency room setting or in the ENT clinic.

[Dr. Ashley Agan]
Do most of your patients already have the diagnosis by the time they get to you?

[Dr. Stephen Schoeff]
Yes, I would say a good portion come to me with a diagnosis. Either they've been into an urgent care or an emergency room and are getting a scan, a CAT scan that might show it, or they're being seen by an ENT consultant, or getting into a general ENT clinic where a careful, flexible laryngoscopy exam might show it. It's also quite possible for these patients to get into an ENT clinic and say just a standard flexible laryngoscopy, it might not be evident. If the stridor isn't particularly noticeable, it can even be missed in that setting as well. I would say the majority of patients have at some point gotten a diagnosis before they end up in my clinic. Probably about, I don't know, I'd say 85 or 90%. Occasionally, I do get patients where they've had stridor, they've had dyspnea for a while and end up in my clinic and we're finding it for the first time.

Listen to the Full Podcast

Idiopathic Subglottic Stenosis Evaluation & Management with Dr. Stephen Schoeff on the BackTable ENT Podcast)
Ep 161 Idiopathic Subglottic Stenosis Evaluation & Management with Dr. Stephen Schoeff
00:00 / 01:04

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History-Taking with Idiopathic Subglottic Stenosis in Mind

Patients with suspected idiopathic subglottic stenosis should be asked about the timing and intensity of their symptoms. Classically, a patient with idiopathic subglottic stenosis will complain of slowly progressive exercise intolerance and increased mucus burden. Conditions that share symptoms with, and are sometimes mistaken for, idiopathic subglottic stenosis include laryngopharyngeal reflux (LPR), paradoxical vocal fold motion (PVFM), granulomatosis with polyangiitis (GPA), and functional dyspnea.

[Dr. Ashley Agan]
Let's think about the patient that hasn't been diagnosed yet. When you're going through your history taking, are there particular questions that you're asking to screen for this diagnosis in particular that's unique or is it your standard list of questions from your laryngologist?

[Dr. Stephen Schoeff]
Yes. I would say, I naturally am more suspicious of it, I would say, than probably the average ENT. I may ask a little bit more about progressive dyspnea, progressive inability to tolerate exercise. I would say the biggest thing about this condition is it tends to move along pretty slowly. Classic timeline is about two years from when somebody starts to have symptoms to when they actually are seeing a laryngologist. Usually by then, their airway is probably 60 or 70% narrowed. The biggest thing for me is that slowly progressive loss of exercise capacity. Because people will describe this, yes, initially, I just couldn't- I used to be able to walk a few miles, then I couldn't walk more than a couple miles. Then now I'm struggling to get up the stairs. I'm having to stop and take breaths as they're talking. Definitely, the people who are presenting in that way, you'll have that clinical suspicion as you hear them talk as well.

Physical Exam Findings in Idiopathic Subglottic Stenosis

Physical examination helps clinicians identify (or note the absence of) signs that suggest alternative etiologies for idiopathic subglottic stenosis. Dr. Schoeff performs a complete head and neck exam on all of his patients, looking for telltale signs of autoimmune diseases with airway involvement. For example, he inspects the nasal cavity to look for septal perforation potentially caused by granulomatosis with polyangiitis (GPA). He then proceeds to in-office bronchoscopy. He uses either 4% lidocaine dribbled onto the vocal folds or, alternatively, a transcricothyroid injection of 2% lidocaine when anesthetizing the patient. During scoping, idiopathic subglottic stenosis will appear as spiraled scarring, whereas iatrogenic subglottic stenosis will appear as thick scarring in a concentric pattern, and autoimmune subglottic stenosis will present with dramatic red inflammation.

[Dr. Stephen Schoeff]
Yes. Obviously starting out with just a routine head-neck exam. I feel like I'm answering the boards.

[Dr. Stephen Schoeff]
But routine head-neck exam. We didn't get too much into autoimmune disease yet, but that's always the overlap there is the potential for autoimmune disease. Looking to see is there a septal perforation, major crusting in the nose, any fluid in the ears, things that make you think of GPA, granulomatosis, polyangiitis, the former Wegener's, and sarcoidosis, a couple other- those can be the big ones. Then listening to the patient breathe, having them do forced inspiration. A rapid through the mouth inspiration can definitely help you to hear whether or not there's that core stridor. Then moving on to some combination of laryngoscopy or an office bronchoscopy. If I know coming in that somebody has stenosis on a CT, we're going to be set up already to plan a bronchoscopy in the clinic. Usually I'm just using a channeled scope where we're going to really spray their nose well, get them a little bit set up. Particularly if they have a small nose, we'll pack the nose just because the camera is a little bigger. Then we will go ahead and dribble some lidocaine onto the vocal folds with sustained phonation, and then that allows me to do a full airway exam down into the trachea and even see the main stem bronchi. In the patient where I don't know yet, say they just get sent to me for a nonspecific complaint, but I'm suspecting that and say I'm not set up with a channeled scope and for whatever reason don't have the ability to switch over to that, sometimes I'll just use transcutaneous, transcricothyroid injection of 2% lidocaine. Just prep them, discuss, tell them that I'm suspicious of something deeper in the airway and that it'll feel a little uncomfortable at first, a little injection of lidocaine and make them cough quite a bit at first to get the lidocaine all through the airway. Most patients actually tolerate that really well in terms of numbing the airway and then you're able to do a full airway exam. With that as well to see the subglottis and the distal trachea even with a normal or just a regular flexible laryngoscope.

[Dr. Gopi Shah]
Then on the scope exam, when a patient does have idiopathic subglottic stenosis, what are you looking for? What does it look like? How does it look different than the patient who has had an intubation history or a reason for subglottic stenosis?

[Dr. Stephen Schoeff]
Oftentimes this idiopathic subglottic stenosis has a fairly trademark look, I would say, and it tends to be this almost spiral pattern to it. The usually slightly red tissue that's spiral. It may be eccentric, it may be concentric, you may have a pretty midline circle, but it may be that the left side is pretty involved, but the right side is less so. The main differences, I would say, that I feel like I see with idiopathic versus say an iatrogenic, which fortunately in my practice, iatrogenic subglottic stenosis is quite rare, that tends to be a thicker appearing scar. Usually doesn't have this spiral pattern to it. It's just usually concentric, thick. It looks more dense and may or may not be located right in this cricotracheal junction area, but obviously can vary a little bit more. Of course, you have the history piece of I was in the ICU for the last six weeks from those patients as well. Then the other one that I would say could be a little harder to differentiate is the autoimmune disease. I would say the patients I've seen who present with GPA that's otherwise been diagnosed, which is going to be by far the most likely thing to present in the subglottis, those patients, it looks horrible. It is extremely red, usually there's a lot of crusting. Oftentimes the vocal folds will be inflamed, and it just looks way more inflamed than I would say the average idiopathic patient looks. They may have a little bit of crusting, but usually it's dramatically more inflamed in somebody who's presenting particularly with a new diagnosis of GPA and even some of these other autoimmune conditions that may affect that area. I've seen lupus affect the subglottis as well, and just tends to really show up with a more significant inflammatory appearance.

Labs & Imaging for Idiopathic Subglottic Stenosis

The history and physical exam results provide most of the information needed to treat idiopathic subglottic stenosis. When ordered, labs and imaging help rule in/out specific etiologies. When GPA could account for airway stenosis, a c-ANCA antibody should be ordered. When c-ANCA is positive, MPO and PR3 antibody tests should follow to confirm GPA. Given the visualization available during bronchoscopy, imaging offers limited value when investigating idiopathic subglottic stenosis. CT scans should be reserved for patients with suspected airway structural abnormalities.

[Dr. Stephen Schoeff]
Usually, ideally, we have a really good exam in-clinic, that we've evaluated the extent of the trachea to make sure this is really isolated to this area, which again tends to be the cricotracheal junction. Then we are going over just the nature of, okay, you have airway stenosis, which is a huge change for somebody, of course, who's coming in largely healthy, thinking that maybe they have- they know something's wrong, but they're trying to figure out what it is. That's a big deal, and just processing that initially with folks is always a first step. Then we start talking about what to do next. I don't necessarily feel like a CT is needed, even though sometimes patients come to me with one. As long as we have a really good exam in the clinic, I don't think a CT is going to add anything. Unless I'm concerned for something else going on or structural abnormality or something like that, which A-frame stenosis or something like that tends to be pretty obvious inside the airway as well. Then in terms of work-up, historically, previously I used to get more labs and I think generally the consensus is that we don't need a ton of lab work to rule out autoimmune disease, in part because many of the labs are so nonspecific. For me now, it's primarily a c-ANCA, and then that'll auto spin off into the MPO and PR3, I believe are the two subtests for GPA. I order that for everybody. To date, in somebody where I did not have suspicion for GPA, I've never seen that be positive, but there's always theoretically that possibility. I don't get ANA and things like that, just because it's not infrequent they're positive, but you send them to rheumatology or communicate with a rheumatologist and they say, what do you do with that? I generally don't, unless I am really suspicious that this is something different.

[Dr. Ashley Agan]
Yes, I've had that experience too. That positive ANA is really common and then you're just like, what are we looking at? What does it mean? Then the rheumatologist is like, nothing, it's not a big deal, why are you sending this patient?

[Dr. Stephen Schoeff]
Exactly.

Podcast Contributors

Dr. Stephen Schoeff discusses Idiopathic Subglottic Stenosis Evaluation & Management on the BackTable 161 Podcast

Dr. Stephen Schoeff

Dr. Stephen Schoeff is a laryngologist at Kaiser Permanente in Tacoma, Washington.

Dr. Ashley Agan discusses Idiopathic Subglottic Stenosis Evaluation & Management on the BackTable 161 Podcast

Dr. Ashley Agan

Dr. Ashley Agan is an otolaryngologist in Dallas, TX.

Dr. Gopi Shah discusses Idiopathic Subglottic Stenosis Evaluation & Management on the BackTable 161 Podcast

Dr. Gopi Shah

Dr. Gopi Shah is a pediatric otolaryngologist and the co-host of BackTable ENT.

Cite This Podcast

BackTable, LLC (Producer). (2024, March 5). Ep. 161 – Idiopathic Subglottic Stenosis Evaluation & Management [Audio podcast]. Retrieved from https://www.backtable.com

Disclaimer: The Materials available on BackTable.com are for informational and educational purposes only and are not a substitute for the professional judgment of a healthcare professional in diagnosing and treating patients. The opinions expressed by participants of the BackTable Podcast belong solely to the participants, and do not necessarily reflect the views of BackTable.

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