Page 740 - Equine Clinical Medicine, Surgery and Reproduction, 2nd Edition

Respir atory system: 3.4 Medical conditions of the lower respir atory tr act 715

VetBooks.ir 3.177 3.178

Fig. 3.178 Cytology of BAL fluid from a horse with
previous pulmonary haemorrhage. Haemosiderin is
visible as dark pigment within pulmonary alveolar
macrophages (arrows). A mast cell (arrowhead) is also
present in this sample.

Fig. 3.177 Haemorrhage noted in the trachea of a
horse with exercise-induced pulmonary haemorrhage, health, but their impact on EIPH has not been dem-
immediately post exercise. onstrated. Commercially available nasal strips have
been shown to reduce upper airway inspiratory
resistance and reduce the severity of EIPH during
Haemosiderin in alveolar macrophages (hae- intense exercise. An emerging treatment is the use
mosiderophages) can be detected in BAL fluid of hyperbaric oxygen therapy in affected horses,
(Fig. 3.178). Although this confirms previous lung although scientific evaluation of the benefits of this
haemorrhage, it is not possible to estimate the time treatment is currently lacking.
or severity of haemorrhage by cytology. Radiography,
ultrasonography and nuclear scintigraphy appear to Prognosis
have limited diagnostic value in the evaluation of In the majority of horses with mild EIPH the progno-
EIPH, and their interpretation is difficult. sis for performance is unaffected, but in more severely
affected animals it may be performance- limiting.
Management A poor understanding of the pathogenesis, progres-
Furosemide is widely used to manage EIPH dur- sion and appropriate treatment of this condition
ing exercise, especially in the Thoroughbred racing makes the prognosis uncertain in such animals.
industry. Studies suggest that 0.5–1 mg/kg of furo-
semide administered i/v 4 hours before strenuous LOWER RESPIRATORY
exercise reduces severity and incidence of EIPH and TRACT NEOPLASIA
is associated with improved racing outcomes. Its use
is prohibited in some racing jurisdictions. Although Definition/overview
this medication may reduce the severity of haemor- Primary pulmonary neoplasias are reported infre-
rhage in some horses it does not prevent bleeding quently in horses and include pulmonary lym-
completely. Currently, several additional treatments phosarcoma, granular cell tumour, pulmonary
are used for EIPH, but their efficacy in treat- adenocarcinoma, bronchogenic carcinoma, pul-
ing and/or preventing this condition is unknown. monary carcinoma, bronchogenic SCC, pulmo-
Bronchodilators, broad-spectrum antimicrobials nary chondrosarcoma and bronchial myxoma
and corticosteroids may improve general pulmonary (Figs. 3.179, 3.180). Affected animals are generally