title: Pneumomediastinum in cats: 45 cases (2000-2010).
abstract: OBJECTIVE
  To characterize the incidence, etiology, presenting complaint, clinical course, and outcome of cats with pneumomediastinum.
  
  
  METHODS
  Retrospective study from the period of January 1st, 2000 to December 31st, 2010.
  
  
  METHODS
  University teaching hospital.
  
  
  METHODS
  Forty-five cats with a radiographic diagnosis of pneumomediastinum.
  
  
  METHODS
  None.
  
  
  RESULTS
  Medical and radiographic records were reviewed to identify cats with a radiographic diagnosis of pneumomediastinum. Clinical data were retrieved, including signalment, history, presenting clinical signs, diagnostic test results, treatment, complications, and survival to discharge. In 31 of 45 (69%) cats the pneumomediastinum was secondary to an obvious inciting cause. General anesthesia with endotracheal intubation and positive pressure ventilation was the most common cause in 17 of 45 (38%) cases. This was followed by trauma in 12 of 45 (27%) cats, and tracheal foreign bodies in 2 of 45 (4%) cats. Spontaneous pneumomediastinum (unknown underlying cause) was diagnosed in 14 of 45 (31%) of cases. Onset of clinical signs and diagnosis of spontaneous pneumomediastinum was preceded by emesis in 6 of 14 cats. Common presenting signs were tachypnea seen in 27 of 45 (60%) cats, increased respiratory effort in 26 of 45 (58%) cats, and subcutaneous emphysema in 30 of 45 (66%) cats. Concurrent pneumothorax was identified in 21 of 45 (47%) cats, pleural effusion in 10 of 45 (22%), and pneumoretroperitoneum in 21 of 45 (47%). The mainstay of treatment was supportive care and treatment of the underlying disease process. The prognosis for recovery was good, with 87% survival until hospital discharge.
  
  
  CONCLUSIONS
  Pneumomediastinum in cats is an infrequently diagnosed condition. It is often secondary to an event such as general anesthesia with endotracheal intubation and positive pressure ventilation but less frequently may occur spontaneously. The prognosis is good with appropriate supportive care.
authors.affiliation: Department of Clinical Studies-Philadelphia, School of Veterinary Medicine, University of Pennsylvania, 3859 Spruce St, Philadelphia, PA 19104, USA. emily.thomas@vets-now.com
authors.forename: Emily K
authors.initials: EK
authors.lastname: Thomas
authors.forename: Rebecca S
authors.initials: RS
authors.lastname: Syring
mesh_terms: D000818:Animals; D002371:Cat Diseases / Q000473:pathology*; D002415:Cats; D005260:Female; D008297:Male; D008478:Mediastinal Emphysema / Q000188:drug therapy / Q000473:pathology / Q000601:surgery / Q000662:veterinary*; D010100:Oxygen / Q000627:therapeutic use; D012189:Retrospective Studies
chemical_list: D010100:Oxygen
keywords: feline; pneumothorax; respiratory system; thoracic injuries; trauma