Felis ISSN 2398-2950

Trachea: collapse

Contributor(s): Elizabeth Rozanski, Penny Watson

Introduction

  • Very rare in cats.
  • Cause: usually narrowing of trachea due to extraluminal mass, rarely idiopathic collapse similar to that seen in small and toy dog breeds, ie failure of tracheal rings to maintain their normal C shape.
  • Occasionally collapse of cervical trachea due to trauma.
  • Signs: classic chronic 'honking' which may be exercise- or stress-related. Palpation or compression of the trachea induces coughing.
  • Diagnosis: radiography, endoscopy, fluoroscopy, to show collapse and exclude other obstructive airway diseases.
  • Treatment: long-term medication may be adequate. Surgery if other problems can be managed adequately.
  • Prognosis: depends on cause of collapse.

Pathogenesis

Etiology

  • Underlying etiology, eg pulmonary edema Lung: pulmonary edema, respiratory infection, allergy, may be identified.
  • Collapse of cervical trachea may be associated with trauma.
  • Lymphosarcoma is most common extraluminal mass, although may be any benign mass of sufficient size.
  • Granuloma or polyp or tumor in trachea may also cause collapse.

Specific

Pathophysiology

  • Rare disorder in cats compared with dogs.
  • Tracheal collapse occurs as the result of failure of the tracheal rings to maintain their normal C shape.
Idiopathic
  • Weakening of the tracheal cartilage allows the rings to adopt a progressively more flattened profile resulting in a reduction in the dorsoventral diameter. As a consequence of the tracheal rings opening, the dorsal ligament becomes elongated and flaccid.
  • Dyspneic respiratory efforts may cause the membrane to be drawn into the tracheal lumen promoting respiratory obstruction - often termed dynamic collapse as it happens during breathing.
Compressive
  • Mass in anterior thorax compresses trachea.
  • Granuloma or polyp in trachea may also result in collapse (see Scherding).
Idiopathic
  • Weakening of the tracheal cartilage   →   progressive flattening   →   reduction in the dorsoventral diameter   →   the dorsal ligament becomes elongated and flaccid.
  • Dyspneic respiratory efforts may   →   mucosa drawn into the tracheal lumen (on inspiration in cervical trachea and expiration in thoracic trachea)   →   respiratory obstruction.

Timecourse

  • Weeks to years.

Diagnosis

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Treatment

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Outcomes

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Further Reading

Publications

Refereed papers

  • Recent references from PubMed and VetMedResource.
  • Johnson L R, McKiernan B C (1995) Diagnosis and medical management of tracheal collapse. Semin Vet Med Surg (Small Anim) 10 (2), 101-108 PubMed.
  • Spaulding G L (1992) Medical management considerations for upper airway disease. Probl Vet Med (2), 419-428 PubMed.
  • Hendricks J C, O'Brien J A (1985) Tracheal collapse in two cats. JAVMA 187 (4), 418-419 PubMed.

Other sources of information

  • Levy & Ford Diseases of the Upper Respiratory Tract. In: The Cat - diseases and Clinical Management. 2nd edn, Vol. 1. Ed: Sherding.


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