Adding to the Diagram
Recently at an appointment, I was discussing my phenotype with my respirologist, and he mentioned my key tissues and, as usual, that my case is complex. For some reason, we always draw diagrams during this part of the discussion. I really value them because they have turned out to explain to me about airway fibrosis and remodeling.1
Severe airway hyperresponsiveness
Severe airways hyperresponsiveness is another term for super twitchy airways (also twitchy airway always make me think of itchy airways which, I guess, while not exactly the same, is similar to that mechanism).2 My crazy inflammation and my ongoing roller coaster ride with eosinophilia, while not all my inflammation is connected to processes related to eosinophilia, it is a major contributor.3
Mucus hypersecretion is the worst part of my asthma. Unfortunately, there is very little that can be done. Although, some of the new biologics look to be promising.4 Airway obstruction is now making an appearance in the diagram as scarring or airway fibrosis. There has been some discussion about this in the past. The discussions seemed to be more theoretical than reality, but I guess it is official now.
Refresher course on airway fibrosis
I needed a refresher course on what airway fibrosis (or airway scarring) is. It is thought to be associated with airway hyperresponsiveness and fixed airway obstruction and a key factor in the pathogenesis of asthma.1 One of the thoughts is that chronic airway inflammation, resulting in airway fibrosis, can lead to airway remodeling. The exact role of inflammation in airway remodeling is controversial, however, it is thought to be a contributing factor. It is thought that inflammation leads to a secondary repair process.2
Airway remodeling can be considered to be structural changes in both the large and small airways. This includes changes in the subepithelial fibrosis, increased smooth muscle mass, enlargement of glands, neovascularization, and epithelial alterations.3
Remodeling changes the airway walls by thickening them, which leads to airway narrowing, bronchial hyperresponsiveness, airway edema, and mucus hypersecretion.5
Identifying airway remodeling
Airway remodeling is measured by lung specimens. While bronchoscopy is safe and minimally invasive. The development of new tools to identify remodeling markers in blood, urine, and sputum have been developed as alternatives to biopsy sampling through bronchoscopy. Corticosteroids are a mainstay of inflammation control and one of the preventive measurements although much is still being learned in hopes that alternative therapies can be developed.4
Airway fibrosis and airway remodeling are linked to poor clinical outcomes in asthmatics. Early diagnosis and hopefully prevention of airway modeling leads to better outcomes in asthmatics. I am hoping that I can keep any further remodeling at bay.
Does cold weather impact your asthma?