Tracheal collapse, chronic bronchitis Flashcards
which finding outside of ref. intervals need not be care about?
unspecific thrombocytosis not unusual in old dogs
Trachea is composed of 35-45 cartilaginous, C-shaped rings joined dorsally by the dorsal tracheal membrane.
Tracheal collapse is
progressive dorsoventral flattening of the
tracheal rings with laxity of the dorsal tracheal membrane.
Tracheal collapse - etiology
Softening of cartilage rings - but why?
Genetic and environmental factors
Primary congenital abnormality suspected
◦ Small dogs with TC are Found to have Decreased: Chondrocytes, glycosaminoglycans, chondroitin sulfate
Secondary factors affecting progression
◦ Obesity, airway inflammation, respiratory infection, intubation, pollutants…
Can be accompanied by bronchial collapse and bronchomalacia.
Tracheal collapse – signalment and clinical signs
Commonly middle-aged and older dogs, but can also be young.
Small and toy-breeds commonly
◦ Yorkshire terrier, pomeranian, poodle, Maltese, chihuahua
Chronic coughing, honking, grunting (worsened by excitement, pulling on the leash, drinking), exercise intolerance, dyspnea, cyanosis, even syncope.
Tracheal collapse - location
Location of the collapse can vary.
◦ Cervical
◦ Intrathoracic
Or both, like in the thoracic inlet. The entire trachea can also see collapse.
Commonly dynamic collapse
◦ Cervical occurs on inspiration
◦ Intrathoracic occurs on expiration
Tracheal collapse severity grading
grades 1-IV
I = 25% collapse (no clinical signs yet, common finding)
II = 50%
III = 75%
IV = 90-100% or shaped like a ‘W’
Tracheal collapse – physical examination
Avoid provoking the cough!
Variable changes in breathing pattern and auscultation.
e.g. Normal breathing pattern or difficulty on inspiration or expiration
or e.g. Normal lung sounds, stridorous sounds or crackles
Tracheal collapse – diagnosis
Signalment: Not really ever found in big dogs or cats.
History of cough (or honk or grunting like a pig), physical examination findings.
Blood work, faecal examination for parasites
! Thoracic and cervical radiographs
! Bronchoscopy
Tracheal collapse – thoracic radiographs
Radiographs are not the best way to diagnose tracheal collapse but can
give a good hint of what is going on.
Study found: Radiographic and endoscopic tracheal collapse -diagnoses
corresponded in 70% of dogs.
- In 44% of dogs, the location was incorrectly evaluated from x-rays
- In 8% of dogs, the collapse was not visible in x-rays
Tracheal collapse – treatment
No curative treatment!
Always medical management and in very advanced cases intratracheal stent (or surgery) which depends on collapse location and severity.
Tracheal collapse can be a medical emergency.
Manage with: Cool environment, harness instead of a collar, weight loss, avoiding excitement and barking.
Tracheal collapse – medical management (4)
Corticosteroids often used:
◦ Oral prednisolone for short courses only, fluticasone inhalation for long-term
Bronchodilator (theophylline):
◦ No effect on large airways but reduces smaller-airway spasm which lowers
intrathoracic pressure and the tendency of larger airways to collapse.
+ Improves mucociliary clearance, reduces diaphragmatic fatigue, reduces cough.
Antitussives if cough cannot be controlled (maropitant, butorphanol).
Antibiotics when needed
Which location of tracheal collapse
occurs on inspiration?
occurs on expiration?
◦ Cervical occurs on inspiration
◦ Intrathoracic occurs on expiration
Tracheal collapse – surgical treatment
If medical management fails and severe clinical signs.
For cervical collapses only
Surgery is largely replaced by intraluminal stents but Extrathoracic Tracheal Ring Prosthesis also possible in cervical tracheal collapses (image).
Tracheal collapse – intraluminal stents
In cases where medical management fails and there are severe clinical signs.
◦ Cervical collapse, intrathoracic collapse
Careful selection of patient and stent size.
Usually inserted in fluoroscopic
guidance.
Complications:
◦ Stent fracture, migration, infection
Bronchomalacia is characterized by
weakness of the wall of principal bronchi and/or other smaller airways supported by cartilage, which lose their integrity, and become less rigid and functionally incompetent.
What are your ddx?
etc.
What is the A-a gradient?
The alveolar to arterial (A-a) oxygen gradient, which is the difference between the amount of the oxygen in the alveoli (the alveolar oxygen tension [PAO2]) and the amount of oxygen dissolved in the plasma (PaO2), is an important measure to help narrow the cause of hypoxemia.
Normal A-a gradient: Means oxygen transfer is working well (usually small difference).
High A-a gradient: Suggests a problem with oxygen transfer, such as in lung diseases like pneumonia, pulmonary embolism, or fibrosis.
what pattern
broncho-interstitial pattern
Chronic bronchitis is
a Common chronic respiratory disease in older dogs (but can happen at any age).
Chronic airway inflammation, bronchial wall thickening and mucus hypersecretion.
Chronic, inexplicable cough on most days in 2 consecutive months in the preceding year.
In left image
