Eosinophilic bronchopneumopathy (eosinophilic bronchitis) is a relatively uncommon respiratory disease of dogs characterized by eosinophilic infiltration of the lung and bronchial mucosa and bronchiectasis and closely resembled human asthma.
The cause of this condition is thought to be a hypersensitivity to inhaled allergens is suspected, particularly fungi, drugs, bacteria and parasites that triggers CD4+ helper cell release of cytokines.
Persistent antigenic exposure is thought to result in chronic irritation of the tracheal and bronchial mucous membranes and inflammation, with eventual epithelial desquamation, hyperplasia of the mucous glands, and airway obstruction. These changes impair mucociliary clearance and predispose to secondary bacterial infections, ultimately resulting in bronchiectasis.
Affected dogs usually present with chronic progressive coughing unresponsive to conservative palliative treatment. A cough can easily be elicited by palpation of the trachea. Thoracic auscultation reveals severe crackles and expiratory wheezes over all lung fields. As the condition worsens, dyspnea and cyanosis may develop and in rare cases, hemoptysis. A seasonality to the condition may be noted in some dogs, that makes it difficult, clinically, to distinguish from chronic pulmonary interstitial fibrosis.
Complete blood (cell) count, serum chemistry panel, and urinalysis are usually unrewarding.
Chest radiographs usually reveal multiple rounded bullae-like structures, predominantly found in the ventral lung fields, consistent with diffuse, severe, cylindrical bronchiectasis.
Diagnosis is by demonstration of an eosinophilic inflammatory cell infiltrate within respiratory tract cytological specimens (tracheal wash or bronchoalveolar lavage fluid).
A differential diagnosis would include tracheal collapse, chronic bronchitis, heartworm disease, pulmonary interstitial fibrosis, pulmonary parasite infection (e.g. heartworm disease, Aspergillus spp, Histoplasma spp), bronchopneumonia, and pulmonary blastomycosis.
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