What is Narrowed Bronchi?
Tracheal collapse is a chronic condition that can become advanced with time. The central and largest windpipe that links to the bronchi (lungs) is called the trachea, which is supported by C-shaped rings. The trachea can be pictured as a snorkel or a vacuum tube that breathes in oxygen to be distributed to the bronchi and circulated within the blood to the central nervous system and the other major organs and areas of the body. The dorsal membrane is tissue membrane that protects the cartilage rings, and as it extends it weakens and becomes flattened to the point where the C-shaped rings become U-shaped. As a result of the C-rings being crushed, the trachea collapses inducing coughing, and struggles to obtain a sufficient amount of O2 to flow through the airways. There is a possibility of this to occur in the trachea within the neck (cervical trachea) or in the chest (intrathoracic trachea).
Tracheal Collapse in dogs is the weakening and crushing of the cartilage rings protecting and surrounding the trachea, inhibiting and obstructing oxygen to flow freely through the air passages through to the bronchi. Tracheal collapse occurs in the neck area when a dog inhales, and happens in the chest as he exhales.
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Symptoms of Narrowed Bronchi in Dogs
- Dry cough
- Rapid breathing
- Gagging or difficulty drinking or eating
- Respiratory distress
- Inability to exercise
- Fainting or collapsing
- Your pet’s appearance may turn blue
Tracheal collapse can be either congenital or it can be an acquired condition. Pertaining to congenital circumstances, the condition is usually more common in smaller toy dogs such as the Pug, Pekingese, Pomeranian, Chihuahua, Maltese, Miniature Poodle, Shih Tzu and Yorkshire Terrier, and canines who are middle aged or older. This is because these breeds are known to be genetically lacking in levels of calcium, chondroitin, glycosaminoglycans, and other natural factors that support bone, cartilage, and joint health. In the case of acquired conditions, it affects generally older dogs, aged 6 and above.
Causes of Narrowed Bronchi in Dogs
Tracheal collapse is known to be prevalent in dogs that have other medical conditions such as heart disease, respiratory disease (especially dogs that live in an avid smoking environment), poor nutrition (especially obesity), and as mentioned previously, as a congenital condition(inherited and present at birth).
Diagnosis of Narrowed Bronchi in Dogs
This condition is fairly simple to diagnosis. Physical examination and the use of X-rays are extremely helpful for your veterinarian to determine the area or region of collapse. The use of a fluoroscopy, which is a moving X-ray, is tremendously useful to assess the exact location of collapse as your dog’s cervical trachea is provoked to induce coughing. A culture of the tracheal tissue may be taken with the use of a bronchoscope. This is a more intrusive technique as this instrument is attached to a fiber optic camera. However, it can take visual pictures to assess the level of inflammation, to determine if there is a bacterial infection, and to assess the severity of the narrowing, which will be graded on a level of 1 to 4.
Treatment of Narrowed Bronchi in Dogs
Immediate hospitalization is required along with sedation if your dog is in respiratory distress and has depleted levels of oxygen. The primary function of the respiratory tract is to circulate oxygen through the blood, and to eliminate carbon dioxide. Oxygen supplementation will be given to ensure that your dog’s tissue and organs will be able to function normally; being deprived of oxygen can lead to organ dysfunction.
Some dogs should never wear collars, but instead, wear harnesses, as they are safer for them, especially if they are prone to pulling and jumping. All smoke or any kind of air pollutants should be eliminated from your dog’s environment. If he is overweight or obese, measures will be taken to ensuring healthy dietary management. Cough suppressants will be given to counter the coughing associated with tracheal collapse. Other medications, such as bronchodilators, will be given to widen the tracheal pathway to enable freer breathing. Anti-inflammatory medications such as corticosteroids, antibiotics (if there is bacteria infection) and tranquilizers/pain killers to sedate anxiety may be prescribed.
It is also common to prescribe other supplements that treat arthritis such as glucosamine, methylsulfonylmethane, and chondroitin, as they are known to strengthen joints, develop bone cartilage and naturally ease pain. In dire cases with extensive damage, surgery may be required. If the collapsed injury occurs in the neck (cervical) or the thoracic inlet (the entrance hole in the thoracic cavity) the use of prosthetic polypropylene rings (plastic rings) will be surgically inserted inside of the trachea. If the collapse occurs in the chest (intrathoracic), a flexible, metal, stent will be inserted inside the trachea in order to keep the air pathways open.
Recovery of Narrowed Bronchi in Dogs
Up to 70% of dogs are responsive to medical treatment, which must be continued up until the end of life, though coughing (in a milder form) may never completely cease. In the instance of surgery, there is an estimated 75-85% survival rate. However, surgery always comes with risks. Dogs having surgery in the neck are at risk for hemorrhage, coughing, and in the worst-case scenario, a paralyzed larynx. Dogs that have stents placed in their chests also are at risk of severe coughing and inflammation. Stents can also be broken or be moved inappropriately as this area is susceptible to movement, causing inflammation. If the inflammation becomes severe, there is a possibility that dense tissue may develop and obstruct the pathways in the air ducts. Therefore, it is imperative to control and reduce coughing to prevent further risk of complications.