24 ECAC
24.1 What this covers
- Excessive (or expiratory) dynamic airway collapse of the posterior membrane (EDAC)
- Tracheobronchomalacia (TBM)
- aka expiratory central airway collapse.
24.2 Learning objectives
- Excessive (or expiratory) dynamic airway collapse of the posterior membrane (EDAC)
- Tracheobronchomalacia (TBM)
- aka expiratory central airway collapse.
- Reference: https://www.mayoclinicproceedings.org/article/S0025-6196(20)30258-5/fulltext
- Often comorbid COPD, GERD/LPR, autoimmune/RP. ICS postulated to be causal in some cases.
- Presentation: nonspecific - ‘seal-bark like cough’, impaired secretion clearance.
- PFT may be obstructive (45%), restrictive (20%) or normal (20%)
24.3 Bottom line / summary
- aka expiratory central airway collapse.
- Reference: https://www.mayoclinicproceedings.org/article/S0025-6196(20)30258-5/fulltext
- Often comorbid COPD, GERD/LPR, autoimmune/RP.
- ICS postulated to be causal in some cases.
- Presentation: nonspecific - ‘seal-bark like cough’, impaired secretion clearance.
24.4 Approach
- ECAC
- Excessive (or expiratory) dynamic airway collapse of the posterior membrane (EDAC)
- Tracheobronchomalacia (TBM)
24.5 Red flags / when to escalate
- TODO: List red flags that require urgent escalation.
24.6 Common pitfalls
- TODO: Capture common errors or missed steps.
24.7 References
- https://www.mayoclinicproceedings.org/article/S0025-6196(20)30258-5/fulltext
- https://photos.collectednotes.com/photos/5187/54348f54-151d-4bda-bfe2-19717d33dbc1
24.8 Source notes
24.8.1 ECAC
25 ECAC
aka expiratory central airway collapse.
Reference: https://www.mayoclinicproceedings.org/article/S0025-6196(20)30258-5/fulltext
Often comorbid COPD, GERD/LPR, autoimmune/RP. ICS postulated to be causal in some cases.
Presentation: nonspecific - ‘seal-bark like cough’, impaired secretion clearance.
PFT may be obstructive (45%), restrictive (20%) or normal (20%)

25.1 Excessive (or expiratory) dynamic airway collapse of the posterior membrane (EDAC)
normal = 50 +/- 20% luminal collapse on forced expiration. 70+% is excessive
25.2 Tracheobronchomalacia (TBM)
abnormal movement of cartilagenous wall (anterior). Can be cartilagenous (splaying at the end of the tracheal cartilage) or circumfrential (e.g. in relapsing polychondritis)