Equine tracheobronchial lavage: comparison of lavage cytologic and pulmonary histopathologic findings.

This study examines the relationship between cell counts from bronchial lavage samples and lung pathology in horses. The data gathered did not show a strong correlation between lavage cellular features and the state of lungs in the test subjects.

Research Methods and Findings

• The study involved bronchial lavage specimens taken from 166 horses. Bronchial lavage is a diagnostic procedure wherein a fluid is sent into the bronchial tree and then recollected for examination. This method is commonly used to diagnose lung diseases.
• The researchers conducted postmortem gross and histologic examinations to establish the pathologic diagnosis of the lungs from these horses. Histograms are representations of the distribution of data, used here to determine varied lung conditions.
• The pathological findings from these examinations were grouped into several categories: normal lungs (92 or 55% of the total), interstitial pneumonia (18, 11%), bronchopneumonia (13, 8%), focal eosinophilia (13, 8%), diffuse eosinophilia (11, 7%), chronic bronchitis (11, 7%), and suppurative bronchitis (8, 5%). Interstitial pneumonia is an inflammation of the lung’s interstitium, bronchopneumonia is a type of pneumonia that invades both the bronchi and the lungs, eosinophilia is a condition caused by an elevated number of eosinophils in the blood, while chronic and suppurative bronchitis are inflammatory conditions of the bronchitis, the former being long-term and the latter associated with pus.
• The main conclusion of the research was that there was little relationship found between cellular features of the lavage specimens and the pathologic status of the lungs of individual horses. In simpler terms, the cell counts from bronchial lavage samples were not reliably predictive of the specific lung conditions the horses were suffering from.

Significance of Study

• This study has notable implications for veterinary pathology and diagnosis, particularly in the field of respiratory diseases in equine species.
• The findings suggest that differential cell counts from bronchial lavage do not provide a reliable diagnostic tool for determining the specific pathologic status of horse lungs.
• This may lead diagnosticians and veterinary clinicians to seek and validate alternative diagnostic procedures or tests when dealing with potential respiratory diseases in horses.