The cause of tracheobronchomalacia (TBM) varies depending on whether a person has primary TBM (also called congenital TBM) or acquired TBM (also called secondary TBM). Most cases of primary TBM are caused by underlying genetic conditions that weaken the walls of the airway (the trachea and bronchi). For example, primary TBM has been reported in people with mucopolysaccharidoses (such as Hunter syndrome and Hurler syndrome), Ehlers-Danlos Syndrome, and a variety of chromosome abnormalities. Primary TBM can also be idiopathic (unknown cause) or associated with prematurity and certain birth defects (such as a tracheoesophageal fistula).[3][1][5] A small proportion of adults with TBM have the primary form but are not diagnosed until adulthood.[4]
Acquired TBM is generally caused by the degeneration (break down) of cartilage that typically supports the airways. In most adults with acquired TBM, the underlying cause of this cannot be identified.[4] Many adults diagnosed with acquired TBM have common respiratory conditions such as asthma, chronic bronchitis and emphysema.[4] Acquired TBM may be associated with inflammatory conditions (such as relapsing polychondritis), exposure to toxins (e.g. mustard gas), enlargement of structures near the airway (such as goiter or a tumor), and complications from medical procedures (such as endotracheal intubation).
Excerted from https://rarediseases.info.nih.gov/diseases/7791/tracheobronchomalacia.
The weakened airway walls--the trachea and the bronchi--are the ones that have the hyaline cartilage that I was researching in the winter of 2018 when I looked into why influenza often brings on pneumonia, usually bacterial pneumonia that is caused by bacteria that normally populate the upper respiratory tract without causing problems. Tracheobronchomalacia appears to be a slow-motion pneumonia.
Because of my research on pneumonia and cartilage, I now keep a combination glucosamine-chondrotitin sulfate supplement in my home and regularly use it whenever someone in my family has a sore throat or a cough. The purpose of the glucosamine is to protect the hyaline cartilage in the upper respiratory tract, and that of the chondroitin sulfate is to help provide the hyaline cartilage with what it needs to rebuild itself well. We suck on the tablets like lozenges so as to get the cartilage-supporting compounds partially aerosolized within the upper respiratory tract and thus deliver them to the surfaces that most need them.
I haven't had that many opportunities to use the glucosamine-chondroitin sulfate supplement recently because it has been summer here, but when we have used it, it seems to stop the progression of the soreness and/or cough and put us on the road to recovery. I hope someone has seen my video (at https://www.youtube.com/watch?v=JnN_OL1J8Vw) or my blog post (see https://petticoatgovernment.blogspot.com/2018/02/glucosamine-to-protect-cartilage-during.html) about the potential of glucosamine to help support the structural integrity of the upper respiratory tract and begun to investigate it for themselves. Perhaps such an effort will lead to better, more effective treatments for tracheobronchomalacia in the future.