EDAC

[evaparodi]

Has anyone got some advice on Excessive Dynamic Airway Collapse?

My specialist didn't have any ideas.

[2greys]

Continuous positive airway pressure or called CPAP appears to be a treatment. A nippy machine (a portable CPAP machine) may help you.

thorax.bmj.com/content/67/1/95

[evaparodi in reply to 2greys]

Thank you!

[Hidden]

So, this is something I’ve looked into quite a bit, because EDAC is often ‘misdiagnosed’ or confused for tracheomalacia and vice versa, and my daughter has a diagnosis of congenital TM/TBM. Apologies if you know all of this already, and feel free to skip over it to the last para if you just want to read what I know about managing it, but over the years, much of the scientific research has interchangeably used terms like malacia and tracheobronchial collapse when TM and EDAC, although sharing almost identical outward symptoms, are two separate conditions. Medics also use terms interchangeably on procedural reports, so they’re not really helping themselves (or us) either. Even a study from Guys and St Thomas three years ago says they refer to both as TM in the study 🤦‍♂️

Bronch is the gold standard diagnostic for both conditions, but diagnosing which is which can be difficult unless you’ve got an experienced specialist who will look for specific clinical factors like the condition (and presence) of cartilage in the trachea to support the diagnosis of TM versus EDAC, along with specifically which wall of the trachea is the source of collapse: EDAC is the posterior wall collapsing more than 50% on expiratory effort, whereas TM tends to be more of a global dysfunction with clear involvement/abnormalities of cartilage. The shape of the collapse can also give some indication, but even then, the clinician may still use the ‘wrong’ term diagnostically. The most accurate and helpful way to diagnose EDAC is actually cine MRI, but there is a massive lack of expertise for being able to accurately read the films for the condition, so its use is very rare. CT scan with inspiratory and expiratory measures is also employed diagnostically with good rates of success, and used quite routinely within the UK. Measures like pulmonary function tests will often demonstrate upper airway dysfunction in the flow-volume loops, along with a distinctive oscillating pattern, and a characteristic ‘notch’ at the start of the graph, but there are no features on spirometry that can define which you’re dealing with, and the features are not unique to TM and EDAC, they can also be seen in things like severe obstructive sleep apnea. Putting the lung function stuff into English, this just means you tend to get a fairly odd looking graph with either condition when you do spirometry, with some characteristic features that demonstrate there’s an upper airway issue. Some people also have results that show an obstructive pattern, but not all. Most non-specialists look at my daughter’s lung function results and think something’s wrong with the test.

Both TM and EDAC are widely found to be acquired conditions, although TM is also known to be congenital, and often found in adult patients with underlying respiratory conditions, or a past history of respiratory illness, people (including children) who’ve had fairly prolonged mechanical ventilation, or some instances of blunt force trauma like car crashes. Some other conditions are also considered to cause airway malacia and/or dynamic collapse (you can have both at the same time), including connective tissue disorders such as Ehlers danlos syndrome and some autoimmune issues such as relapsing polychondritis. If you’re scientifically minded and you like a good research paper, then this is quite an informative read that goes through how the two conditions are different despite being used interchangeably:

onlinelibrary.wiley.com/doi...

The problem with both TM/TBM and EDAC is actually an astounding lack of research. We know they exist in the general population, we know they’re probably fairly common within the respiratory illness cohort, and we know the difficulties they can cause in terms of breathlessness, coughing, exercise intolerance, recurrent infection and difficulty clearing secretions, but there have been very few prospective studies with regards to understanding the conditions properly, or measures to better manage them. If you have an underlying respiratory issue warranting chest clearance physio, or utilise physio when you have a chest infection, then the formal recommendations are that you want to be using a technique that utilises positive expiratory pressure (PEP) as this splints collapsed airways open and enables improved clearance. If you have phlegm to clear in your throat, gentle manoeuvres are more helpful than coughing - because when you cough, the airway collapses - so wherever possible gentle huffing is the best option, preferably through some kind of tube. We use peak flow tubes, but the idea is that by having the mouth sealed around the tube, it offers resistance and reduces the collapse of the airway when trying to clear. More broadly, unfortunately there is very little in the way of actual treatment unless the impact is life-threatening. CPAP is the mainstay for fairly severe cases, and even if that’s not deemed appropriate during the day in your case, it would be worth establishing to what extent it impacts on you during the night: some people have clinically significant problems whilst sleeping as a result of relaxation exacerbating the degree of collapse. Tracheal stenting is sometimes performed in severe cases but with generally poor outcomes, particularly in relation to long term, post-operative infections. Tracheoplasty is also an option but not popular. For the vast majority of people with stable TM/EDAC, the primary feature of management is appropriately treating any underlying respiratory issues, including rapid and sufficient treatment of infections, and recognising that the patient will generally experience more chest infections and be more difficult to manage than others.

I hope you didn’t think I was trying to teach you to suck lemons, and that some of it was useful.

[Michowls2 in reply to Hidden]

Thanks for that information I’ve learnt more from that reply than I have from my specialist. My main frustration is no one seems to know what edac is when you arrive in a&e and dismiss it.

[Hidden in reply to Michowls2]

Glad you found it helpful 👍 To be honest, even amongst specialists it seems to be quite a specialist subject; we’re ‘lucky’ in that my daughter also has cystic fibrosis, and acquired TM and/or EDAC occurs in around 30% of adult patients with cf, so although still in paeds, her cf team are familiar with airway collapse and the implications. It may not be relevant to you, but if you also have an underlying respiratory condition that tends to make you productive, a paper was published last year that was co-written by a physio from the hospital she’s under (the Royal Brompton) making consensus recommendations for the first time about airway clearance and chest physio in patients with collapse of the large airways.

openres.ersjournals.com/con...

If it’s causing you major problems, the other thing to potentially consider would be asking for a referral to somewhere that is more au fait with EDAC, even if it was just to explore if there was any treatment you might benefit from in relation to that?