Canis ISSN: 2398-2942

Lung: chronic pulmonary interstitial disease

Contributor(s): Lynelle Johnson

Introduction

  • Seen mostly in older West Highland White Terrier West Highland White Terrier and the Cairn Terrier Cairn Terrier.
  • Cause: paraquat poisoning, pneumocysis, other causes unknown.
  • Signs: tachypnea, exercise intolerance, variable coughing.
  • Diagnosis: difficult - often made on basis of exclusion of all other possible causes.
  • Treatment: manage clinical signs.
  • Prognosis: variable response to therapy, tends to progress respiratory failure.

Pathogenesis

Etiology

  • Chronic lung injury may trigger irreversible damage to the lung interstitium.

Old dogs

  • Increased interstitial lung patterns are common incidental findings and may be part of the aging process.
  • Chronic interstitial changes are noted commonly in the aged West Highland White Terrier and Cairn Terrier and the condition is seen most in these breeds. The etiology of the changes in these breeds is not known.

Pathophysiology

  • Pneumocystis infection may be related to an underlying immune defect.
  • With idiopathic disease, changes are probably secondary to other underlying respiratory and non-respiratory diseases, with replacement of alveolar walls and the lung interstitium with fibrous tissue.
  • The overall effect is a reduction in lung compliance, which reduces inspiratory capacity and the animal's ability to increase tidal volume when necessary.
  • The exact mechanisms underlying the development of chronic interstitial changes in the lungs of dogs is not known. However, such changes are commonly recognized on thoracic radiographs in animals with chronic respiratory disease.

Timecourse

  • Months 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.
  • Lobetti R G, Milner R & Lane E (2001) Chronic idiopathic pulmonary fibrosis in five dogs. JAAHA 37 (2), 119-127 PubMed.
  • Corcoran B, Dukes-McEwan J, Rhind S & French A (1999) Idiopathic pulmonary fibrosis in a Staffordshire bull terrier with hypothyroidism. JSAP 40 (4), 185-188 PubMed.
  • Brownlie S E (1990) A retrospective study of diagnosis in 109 cases of canine lower respiratory disease. JSAP 31 (8), 371-376 VetMedResource.


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