Tracheal collapse

As tracheal collapse is known in domestic dogs collapse of the windpipe ( trachea Lat. ), by the softening of the supporting cartilage rings. This results in a decrease especially of the vertical diameter and thus a narrowing of the trachea, which can lead to severe breathing problems. In humans, a tracheal collapse occur as a result of tracheomalacia. The tracheal collapse dogs can usually be a long time dominated conservative with medications, surgical treatment is possible, but expensive and not always successful.

Occurrence and causes

A tracheal collapse is mainly used for domestic dogs, especially in dwarf breeds (Yorkshire Terrier, Chihuahua, Maltese, Pomeranian and Miniature Schnauzer ), above. Especially middle-aged animals are affected. Occasionally, a tracheal collapse even in domestic horses and cattle on, very rarely in domestic cats.

The cause of the disease has not been elucidated. Probably the tracheal collapse is genetic ( hereditary ). But the genesis by the coincidence of various factors ( multifactorial ) is not excluded. The disease can be favored by a number of other factors, including respiratory infections, allergies, narrowing of the trachea, toxic dusts and vapors as well as heart failure.

Pathogenesis

The chondromalacia comes about by changes in the cartilage matrix, mainly by a reduced content of glycosaminoglycans (especially chondroitin sulfate ) and glycoproteins, whereby the water-binding capacity of the cartilage and thus its elasticity decreases. The cell number in cartilage is lowered and the ground substance is porous. The decrease of the air tube inside diameter is accompanied by an increased flow resistance of the air and leads to turbulence.

Secondarily it comes through the tracheal collapse to a degeneration of the ciliated epithelium, hypertrophy of the glands in the lining of the trachea, sometimes even to the formation of polyps.

Clinic

The clinical presentation is highly variable, a tracheal can long remain without symptoms and the degree of narrowing does not correlate with the extent of clinical symptoms. The symptoms develop gradually and the disease progresses slowly.

A typical early appearance is a paroxysmal cough, which occurs especially when excited or greater physical burden. A collar can exert on a leash pressure on the trachea and thus trigger the coughing fits during heavy train. The cough occurs first as a "dry" cough in appearance, with the incoming secondary changes (increased mucus secretion by the glandular hyperplasia ) he may turn into a "wet" cough. In addition, there is a reduced performance of the animal.

Clinically, as a result of an increased " tracheal breathing sound " ( stridor trachealis, mostly in the form of humming tones), an increased respiratory rate ( tachypnea ) and increasing difficulty breathing (dyspnea ) on. These occur at the location of the neck portion of the trachea, especially during inspiration ( inhalation), wherein the chest portion manifestation more during exhalation ( expiration) on. The reason for this is the fact that an instability in the neck area of the collapse is caused by the inhalation resulting vacuum, while instability in the breast area usually collapse of the trachea through the occur during exhalation pressure in the chest cavity (based within the pressure the trachea ) to the cause has. With increasing dyspnea there is a lack of oxygen which manifests itself in a blue coloration ( cyanosis) of the mucous membranes.

Diagnosis

For localization in the neck portion of the trachea, the softening of the cartilage rings can be assessed using scanning (palpation ), which usually also cough is triggered. For more information, the X-ray imaging of the trachea deliver. The definitive diagnosis, however, can only be delivered by endoscopy.

Differential diagnoses

Must be differentiated primarily inflammatory diseases of the trachea ( tracheitis ) by infections or allergies. Also, foreign bodies and tumors in the trachea can cause narrowing and tracheal breath sounds. Finally, it can come about a narrowing of the trachea by compression from the outside through magnification of adjacent organs. Here in particular the trachea come adjacent organs such as the deep cervical and the anterior and middle mediastinal lymph nodes ( Lnn. deep cervical and mediastinal cranial et medii ), thyroid and parathyroid glands in the question. Also abscesses and bruising in the neighborhood of the trachea can lead to the compression from the outside.

Quite frequently occurs a compression of Endaufzweigung trachea due to an increase of the left atrium of the heart, which in turn cause an insufficiency of the mitral valve of the heart ( Klappenendokardiose ). Here, the symptoms in addition to the narrowing of the lumen is significantly enhanced by the constant mechanical irritation of the trachea due to the cardiac motion.

In some breeds ( English Bulldog, Boston Terrier) and to a hereditary growth disorder of the windpipe (trachea hypoplasia ) must be considered.

Therapy

A causal therapy is not possible.

Conservative the disease can be controlled relatively long in most dogs. Simple measures, such as the use of a chest harness instead of a collar, the avoidance of excessive physical exertion and avoid obesity can be carried out by the dog owners themselves.

To alleviate the symptoms antitussive agents, bronchodilators can briefly also anti-inflammatory glucocorticoids are used (eg, theophylline) or. Another conservative therapeutic approach is the use of parasympatholytics ( atropine, also in combination with diphenoxylate, such as Lomotil ®).

In the experimental stage is the onset of originally developed for human medicine stents to ensure a passive support of the trachea. Although this method is considered to be currently the most effective method of treatment of the disease ( almost 70 percent of patients are determined to be significant clinical improvement after the procedure ), it has not yet become standard therapy. Main reason for this are the high costs of the stent; Complications can also occur if the unstabilized of the endoprosthesis shares of the trachea and main bronchi collapse. In some animals, occurs due to the accumulation of secretions in the area is not completely resting against the tracheal wall stent portions remain on cough. Rarely, impaired breathing by excessive formation of granulation tissue; However, these symptoms seem to be rectified with the use of glucocorticoids. Anecdotal mention collapsing a stent with subsequent narrowing of the airway. As an alternative to the surgical stent, the fixation of the air tube may be placed around the trachea a plastic frame on the non- weiteseten procedure. As further possibilities interventions on the upper -lying membrane of the trachea as well as direct manipulation of the cartilage rings are described. These techniques have in common is that they are highly invasive and surgically very sophisticated process.