Tracheal Collapse (Tracheobronchomalacia)

TL;DR. Tracheal collapse is a progressive weakening of the windpipe's structural rings, causing airway obstruction, a signature 'goose-honk' cough, and respiratory distress that requires careful medical management or, in severe cases, surgical intervention.

Tracheal collapse occurs when the normal round cartilage rings flatten, narrowing the airway.

What is it?

Tracheal collapse, scientifically known as tracheobronchomalacia (TBM), is a chronic, progressive disease of the respiratory tract. To understand this condition, it helps to picture the trachea (the windpipe) as a flexible, vacuum-cleaner-like hose. In a healthy animal, this tube is held open by a series of rigid, C-shaped rings made of hyaline cartilage. The open top of the "C" is bridged by a smooth muscle sheet called the dorsal tracheal membrane. Together, these structures keep the airway wide open, allowing air to flow freely to and from the lungs during breathing.

In animals suffering from tracheal collapse, these cartilage rings gradually lose their structural integrity. They lose essential water-retaining molecules, become soft and floppy, and begin to flatten. At the same time, the dorsal membrane becomes stretched, loose, and redundant. When the animal inhales or exhales, the changes in pressure cause this loose membrane to sag into the airway, while the flattened cartilage rings fail to support the tube. This results in a dynamic airway obstruction, meaning the windpipe narrows or completely pinches shut as the animal breathes.

Veterinarians grade the severity of tracheal collapse on a scale from I to IV:

• Grade I: The cartilage rings maintain their normal shape, but the dorsal membrane is slightly loose, reducing the airway space by about 25 percent.
• Grade II: The cartilage rings are slightly flattened, and the membrane sags further, reducing the airway space by approximately 50 percent.
• Grade III: The cartilage rings are nearly flat, and the membrane is highly redundant, reducing the airway space by 75 percent.
• Grade IV: The cartilage rings are completely flat or may even curve backward, entirely blocking the airway.

As a leading veterinary surgical reference describes Grade IV collapse:

"Grade IV: The trachealis muscle is lying on the dorsal surface of the tracheal cartilages. The tracheal cartilages are flattened and may invert dorsally. The tracheal lumen is essentially obliterated."

While this condition is most famous in toy breed dogs, it is also diagnosed in cats and horses. Because clinical cases in cats and horses are rare, much of our diagnostic and treatment guidance for these species is extrapolated from canine protocols, though horses present unique anatomical challenges due to their size and athletic demands.

Causes & risk factors

Tracheal collapse is primarily considered a congenital condition, meaning animals are born with a genetic predisposition to weaker tracheal cartilage. Over time, normal wear and tear, combined with aging, causes the cartilage to deteriorate further.

As noted in a leading veterinary internal medicine textbook:

"Overall, although any signalment is possible, TBM occurs most commonly in middle-aged toy and miniature dogs. Signs may occur acutely but then may slowly progress"

Several secondary factors can trigger the onset of symptoms or rapidly accelerate the progression of the disease:

• Obesity: Excess body fat puts physical pressure on the chest and neck, increasing the effort required to breathe and worsening airway collapse.
• Respiratory Infections: Concurrent bacterial or viral infections cause inflammation and coughing, which further damages the delicate lining of the trachea.
• Airborne Irritants: Exposure to cigarette smoke, household dust, aerosol sprays, and outdoor allergens can trigger coughing fits that exacerbate the collapse.
• Cardiomegaly: An enlarged heart can physically press upward against the main airways (bronchi), worsening the collapse in the chest cavity.
• Intubation Trauma: Occasionally, the placement of an endotracheal tube for anesthesia can temporarily irritate a pre-existing, silent tracheal weakness.

Signs to watch for

Symptoms of tracheal collapse can range from mild, occasional coughing to life-threatening respiratory emergencies. The hallmark sign is a dry, harsh, paroxysmal cough that sounds remarkably like a honking goose.

• Goose-honk cough (Cardinal) – A loud, dry, honking cough that often occurs in spasms, especially when the animal is excited, active, or pulling on a collar.
• Nonproductive cough (Cardinal) – A dry cough that does not produce phlegm or mucus.
• Exercise intolerance (Common) – Reluctance to walk or play, tiring quickly, or sitting down during exercise.
• Respiratory distress (Common) – Labored breathing, rapid breathing, or breathing with an open mouth and flared nostrils.
• Gagging after eating or drinking (Occasional) – The physical act of swallowing can irritate the sensitive, collapsed trachea, leading to a gag or retch.
• Expiratory wheeze (Occasional) – A high-pitched whistling sound heard specifically when the animal exhales.
• Stertor (Occasional) – A low-pitched, snoring sound originating from the upper airway.
• Stridor (Occasional) – A high-pitched, harsh, vibrating sound that indicates severe upper airway obstruction.
• Hypoxemia (Occasional) – Low levels of oxygen in the blood, which can cause weakness, lethargy, or blue-tinged gums.

Dogs in respiratory distress will often extend their necks and breathe with an open mouth to maximize airflow.

How vets diagnose it

Diagnosing tracheal collapse requires a systematic approach to rule out other causes of coughing, such as heart disease, pneumonia, or airway parasites. Your vet will start with a thorough physical examination, which often includes tracheal palpation. Gently touching or massaging the trachea in the neck will easily trigger a characteristic coughing fit in affected animals.

To confirm the diagnosis and determine the severity, your vet may recommend several diagnostic tests:

• Thoracic and cervical radiography (X-rays): X-rays of the neck and chest are a standard starting point. However, because tracheal collapse is dynamic, standard X-rays can miss the collapse if they are taken when the animal is not actively breathing in or out.
• Fluoroscopy: This is a continuous, real-time X-ray video that allows your vet to watch the trachea expand and collapse as your pet breathes, coughs, and swallows. It is highly sensitive for identifying dynamic collapse.
• Computed tomography (CT): High-resolution CT scans can provide detailed three-dimensional images of the airway, helping to map out the exact areas of narrowing.
• Tracheal ultrasound: A non-invasive tool that can visualize the cartilage structure in the neck area.
• Tracheoscopy and bronchoscopy [GOLD STANDARD]: Under light anesthesia, a specialist inserts a tiny, flexible camera into the windpipe. This allows direct visualization of the entire airway, precise grading of the collapse, and the collection of fluid samples (bronchoalveolar lavage) to check for underlying infections or inflammation.

Your vet will also recommend routine blood work to assess your pet's overall health and screen for secondary complications. As a standard small animal critical care manual notes:

"Complete blood count and serum chemistry evaluation should be performed in patients with tracheal collapse to look for inflammatory leukogram changes consistent with infection and evidence of liver dysfunction (elevated ALT and bile acids), which has been documented in dogs with tracheal collapse and is suspected to be secondary to hypoxemia."

Treatment options

Treatment for tracheal collapse is tailored to the severity of the disease. Most patients with mild to moderate collapse (Grades I and II) can be managed successfully with medical therapy and lifestyle changes.

First-Line Medical Therapy

Medical management focuses on reducing inflammation, controlling cough cycles, and dilating the airways:

• Glucocorticoids (Corticosteroids): These powerful anti-inflammatory medications help reduce swelling and irritation in the tracheal lining, which breaks the cycle of coughing and further inflammation. They are often prescribed as short oral courses or administered via inhalers.
• Anticholinergics / Parasympatholytics (such as Atropine): These medications help reduce excessive secretions in the airway and relax the smooth muscles of the respiratory tract.
• Cough Suppressants (Antitussives): Controlling the cough is vital, as coughing physically irritates the trachea and worsens the collapse.
• Bronchodilators: These help open up the smaller airways deeper in the lungs, reducing the overall effort required to breathe.

Environmental and Lifestyle Management

Medical therapy must be paired with strict environmental controls to be effective:

• Weight Loss: Keeping your pet at a lean body weight is one of the most effective ways to manage this disease. Even a small amount of weight loss can dramatically improve breathing.
• Harness Only: Never use a neck collar on a pet with tracheal collapse. Switch exclusively to a body harness that does not put pressure on the windpipe.
• Air Quality: Eliminate environmental triggers. Avoid smoking around your pet, use air purifiers, and minimize dust and strong chemical cleaners in the home.

As outlined in a leading veterinary internal medicine textbook, initial management should involve:

"Initiate trial therapy with anti-Mycoplasma drug. Initiate trial environmental manipulations to minimize potential allergen and irritant exposure."

Surgical and Interventional Options

For patients with advanced disease (Grades III or IV) that fail to respond to medical management, surgical intervention may be necessary. These procedures are highly specialized and typically performed by board-certified veterinary surgeons:

• Extraluminal Prosthetic Rings: Plastic rings are surgically placed around the outside of the trachea in the neck to hold it open. This is highly effective for neck-level collapse but cannot be used for collapse inside the chest cavity.
• Intraluminal Stents: A self-expanding metallic mesh tube (stent) is placed inside the trachea using a camera (endoscope). This holds the airway open from the inside. While highly effective at restoring immediate breathing, stents carry risks of long-term complications, such as metallic fatigue, stent fracture, or the growth of scar tissue over the stent.

Prognosis

Many patients with tracheal collapse respond well to medical management and environmental controls, enjoying a good quality of life for several years. However, because this is a progressive disease, the structural integrity of the windpipe will continue to decline over time.

Patients that fail conservative therapy and require surgical intervention face a more guarded prognosis. While procedures like stenting can be life-saving, they carry significant potential morbidity, requiring lifelong monitoring, regular follow-up imaging, and ongoing medical management.

In cats and horses, where tracheal collapse is exceedingly rare, long-term prognosis data is limited, and outcomes are highly dependent on the individual animal's response to extrapolated canine therapies.

Prevention

Because tracheal collapse is a congenital, structural defect, there is no known way to prevent the disease from developing. However, you can prevent or significantly delay the onset of clinical signs and slow the progression of the disease through proactive lifestyle management:

• Maintain your pet at an ideal body weight from puppyhood.
• Use a harness instead of a neck collar for all walks.
• Keep your home environment free of smoke, aerosols, and heavy dust.
• Seek prompt veterinary care for any respiratory infections or coughing.

When to call your vet

Tracheal collapse can escalate into a life-threatening crisis if the airway becomes severely obstructed. You should contact your veterinarian if you notice an increase in the frequency or severity of your pet's coughing fits.

Seek immediate emergency veterinary care if your pet exhibits any of the following red-flag signs:

• Blue, purple, or pale gums and tongue (cyanosis)
• Fainting, collapsing, or losing consciousness during a coughing fit
• Extreme difficulty breathing, characterized by a sucking in of the chest and abdomen
• An inability to calm down or rest due to constant struggling for air
• A high-pitched, whistling or squeaking sound with every breath (stridor)

For specific breeds

Tracheal collapse is highly associated with specific toy and miniature dog breeds. If you own any of the following breeds, you should be highly vigilant for the early signs of a mild, dry cough:

• Yorkshire Terrier
• Poodle (Toy and Miniature)
• Pomeranian
• Chihuahua
• Maltese

In these breeds, the genetic predisposition to cartilage weakness is well-documented. Implementing lifestyle modifications—such as using a harness and maintaining a lean body weight—early in life is highly recommended to protect their sensitive airways.

Sources

• Small Animal Internal Medicine, 5th Edition, pages 343-344.
• Current Techniques in Small Animal Surgery, 5th Edition, page 416.
• Small Animal Critical Care Medicine, 2nd Edition, page 120.