Interpretation of multisegment bronchoalveolar lavage in cats (1/2001-1/2011).

Abstract

Background: Cytologic results from bronchoscopic BAL in cats with naturally occurring respiratory disease have not been reported, and the clinical utility of multisegment lavage has not been evaluated.

Hypothesis: BAL cytology from 2 separate lung segments in cats will have similar cell counts, cytologic interpretation, or both.

Animals: Eighty-seven cases in 85 cats (2 examined twice) with naturally occurring lower respiratory disease.

Methods: A combined prospective/retrospective evaluation of all cats with multisegment BAL was performed. BAL fluid was evaluated for total nucleated cell counts, differential cell counts, and cytologic characteristics at each lavage site. BAL fluid was categorized as eosinophilic, neutrophilic, lymphocytic, hypercellular, or mixed. Radiographs were assessed for diffuse or focal disease.

Results: Clinical diagnoses included inflammatory airway disease (n = 63), pneumonia (n = 15), neoplasia (n = 6), and undetermined (n = 3). Total nucleated cell counts varied between sites regardless of radiographic evidence of focal or diffuse radiographic disease. In 28/87 cases (32%), cell counts differed between lavage sites by 2.2-40 fold. BAL yielded similar cytologic interpretation of inflammation in 45/87 (52%) cases. In 8/14 cases that had BAL performed at the site of a focal radiographic infiltrate, as well as at a site of diffuse infiltrates, the same inflammatory interpretation was made at each site.

Conclusions and clinical importance: Total and differential cell counts in BAL fluid often differ between lung segments in cats with lower respiratory disease, and caution is warranted when using a single BAL cytology to define the inflammatory response in cats with spontaneously occurring lower respiratory tract disease.