Introduction

• A group of non-infectious, non-neoplastic diseases characterized by inflammation and/or fibrosis of the interstitium of the lung.
• Cause: can be primary or secondary to hematogenous or inhaled irritants.
• Signs: tachypnea, exercise intolerance, variable coughing.
• Diagnosis: difficult. Radiography and CT can be suggestive. Definitive diagnosis requires lung biopsy.
• Treatment: manage clinical signs and secondary pulmonary hypertension.
• Prognosis: variable response to therapy, tends to progress respiratory failure.

Pathogenesis

Etiology

• Primary/idiopathic.
• Secondary:
  • Inhaled irritants, eg dust, asbestos, silicosis, fumes, allergens.
  • Hematogenous insults, eg drugs, immune-mediated, systemic disease.
• Miscellaneous, eg radiation therapy.
• Idiopathic pulmonary fibrosis (IPF) Idiopathic pulmonary fibrosis is a familial interstitial lung disease in West Highland White Terriers.

Pathophysiology

• Pulmonary fibrosis is the end-stage lesion for many different disease processes.
• Chronic lung injury triggers inflammation and fibrosis resulting in irreversible damage to the lung interstitium. The alveoli and bronchi may also be affected.
• The overall effect is impairment of gas exchange and a reduction in lung compliance, which reduces inspiratory capacity and the animal's ability to increase tidal volume when necessary.

Timecourse

• Months to years.

Diagnosis

Treatment

Outcomes