Tracheal collapse is a common respiratory condition usually found in middle-aged toy and small breed dogs. The collapse is thought to occur secondary to a genetic predisposition to have weak cartilaginous rings, resulting in an easily compressible trachea. These tracheal rings may collapse spontaneously or when there is an increase in respiratory pressures, leading to the clinical signs of tracheal collapse. Collapse may occur in the intrathoracic trachea, extrathoracic trachea, bronchi, or any combination of these locations.
Dogs with tracheal collapse usually have a history of a progressive cough that is dry, hacking or "goose-honking" and often more notable with excitement, exercise, eating or drinking. On physical examination cough may be easily elicited upon palpation of the trachea. A honking cough may be visualized in the exam room, but lack of eliciting a cough or hearing a cough does not rule out the possibility of collapse. Stridor, expiratory wheezes or grunting may also be noted during breathing. Dogs with severe collapse may demonstrate dyspnea either upon inhalation (extrathoracic collapse) or exhalation (intrathoracic collapse). Hepatomegaly or obesity may also be noted. Usually the remainder of the physical examination is normal.
Diagnosis is made b
y appropriate clinical signs in conjunction with imaging. Thoracic radiographs should in
clude the entire trachea, and should be taken upon both inhalation and exhalation. Supportive changes include narrowing of
the trachea and/or bronchi on lateral views, or undulating tracheal margins (see figure 1). Thoracic radiographs cannot exclude the diagnosis of collapsing trachea, as collapse is often dynamic, and may only be present during one particular phase of respiration or during coughing. Fluoroscopy provides a video image
o
f the airways, so allows for examination upon inhalation an
d exhalation, as well as evaluation of airways during an induced cough. It ma
y also more accurat
ly assess the severity of the collapse. Tracheoscopy is an additional excellent add
itional diagnostic modality that not only can be utilized for diagnos
is, but can also allow for collection of airway samples for cytology and culture to rule out other concurrent or alternative disorders (see figure 2).
Treatment should initially consist of pharmaceutical therapy and weight management. Weight management alone has been shown to improve clinical signs in obese patients, and is a very important part of treatment. Pharmaceutical therapy is aimed at breaking the cycle of coughing, treating for any existing inflammation or infection, and keeping intrathoracic pressure low via bronchodilators to help prevent collapse of larger airways. Breaking the cycle of coughing usually requires treatment with cough suppressants such as hydrocodone or butorphanol. It might also be necessary to provide sedation (acepromazine, others) during times of increased anxiety or excitement. These sedatives can be used on a daily or "as needed" basis. Antibiotic therapy may be indicated if secondary bacterial infection is suspected, which can easily occur due to a dysfunctional mucociliary apparatus. A short course of anti-inflammatory steroids can be helpful if inflammation and edema of the airway are suspected due to prolonged or more severe coughing.
If medical therapy fails to stabilize clinical signs, surgical intervention with extra-tracheal ring placement or placement of an intrathoracic stent (see figure 3) may be necessary. These procedures should only be utilized when medical management has been attempted and is failing, and it is important to notify owners that medical therapy will still likely be necessary following surgical treatments. Tracheal ring placement is only effective for extrathoracic collapse. Intratracheal stents are placed under anesthesia using fluoroscopic-guidance, with the goal of expanding and holding open the collapsed trachea. Stenting is the only option available for intrathoracic collapse, but can also be used for cases of extrathoracic collapse.
Tracheal stents can be life-saving for patients failing medical management, but are not without complications. The most common complications associated with tracheal stents include granuloma formation (see figure 4), infection, stent migration, or fracture of the stent. Although tracheal collapse is a progressive disease even with interventional therapies, reported survival times are 75% >1 year, and 58% >2 years following stent placement. If you have a case in which further investigation or treatment of tracheal collapse is desired, Alameda East can assist you with fluoroscopic examination, tracheoscopy and sampling, and stent placement.
Dr. Scott received a BS in zoology from the University of Oklahoma, and then obtained her DVM at Oklahoma State University in 2003. Following a one-year internship at Kansas State University, she went on to complete her small animal internal medicine residency at Texas A&M University. Dr. Scott became board certified by the American College of Veterinary Internal Medicine in Small Animal Internal Medicine, and continued to work in the small animal internal medicine section at Texas A&M University.
Dr. Scott brings her skill in numerous interventional radiology techniques to us here at VCA Alameda East. Her interests primarily include gastroenterology, infectious diseases, urology, and minimally invasive procedures. She is proficient in all endoscopic procedures. She is also a member of the American Association of Feline Practitioners.
