Pulmonary Infiltration with Eosinophilia

Also known as : PIE - Eosinophillic Lung disease

Introduction

Pulmonary Infiltration with Eosinophilia (PIE) is a broad term describing an inflammatory lung disease in which the predominant infiltrating cell is the eosinophil. It is thought to be an immune mediated condition where the airway abnormalities are a consequence of a hypersensitivity reaction to an unidentified allergen such as microfilariae of heartworms, lungworms, chronic bacterial or fungal infections (eg, histoplasmosis, aspergillosis), viruses, external antigens, and unknown precipitating factors.
Eosinophillic pulmonary granulomatosis is a severe type of PIE seen in dogs and is characterzied by the development of nodules and hilar lymphadenopathy. It is most often associted with a hypersensitivity reaction to microfilarie in heartworm infection.

History & Clincial signs

Eosinophillic lung diseases are seen in young and older dogs. It is rare in the Cat.
Affected dogs usually present because of slowly progressive respiratory signs such as a cough, increased respiratory effort and exercise intolerance, wheezing and occasionally haemoptysis may be seen.The cough may be mild or severe, productive or nonproductive, and progressive or nonprogressive. Systemic signs are rarely present but may include anorecia and weight loss. There may be a history of a recurring cough which is unresponsive to antibiotics but often responsive to corticosteroid therapy. The clinical signs may be seasonal in appearance.
Severely affected animals may exhibit moderate to severe dyspnea and cyanosis at rest.

Diagnosis

Physical examination

Physical examination is largely normal. Thoracic auscultation may reveal crackles or expiratory wheezes.

Radiography

The most comon radiographic finding is a diffuse Interstitial lung pattern, a bronchial and/or alveolar pattern may also be visible. Eosinophilic Pulmonary Granulmatosis results in the formation of nodules, usually with indistinct borders. Consolidation of lung lobs and a hilar lymphadenopathy may also be seen.

Bronchoscopy

Bronchoscopy may reveal increased amounts of mucous in the airways which may have a greenish appearannce