Cytology and bacteriology of bronchoalveolar lavage on horses suffering from exercice-induced pulmonary haemorrhage

Cytological and bacteriological analyses of bronchoalveolar lavages (BAL) from 32 horses suffering from exercise induced pulmonary haemorrhage (EIPH) and from 10 healthy horses were performed. The age, sex ratio and the races were similar between the 2 groups. The endoscopic examination revealed a left larynx hemiplegia in 5 diseased animals. Mild to severe inflammatory lesions within bronchus and bronchioles were also seen but haemorrhage signs were only evidenced in 3 horses with EIPH. Although the difference was not statistically significant because of a strong value dispersion, the overage cellular density of BAL was more elevated in diseased horses and the strongest value was observed in this group. The leukocyte formula were similar between the 2 groups; however, 4 EIPH horses exhibited a marked increase of neutrophil counts (>36%). In addition, hemosiderophages were evidenced by Peris coloration in 72% of diseased animals and in 30% of healthy horses. Potentially pathogen bacteria were isolate from BAL in diseased horses as well as in controls. Theses results suggest that cytological analysis of BALF may be helpful to diagnostic through hemosiderophage detection (although false positives occur in healthy horses) and that an inflammatory response would partially be involved in the aetiology of this syndrome.