| dc.description.abstract | Even though the respiratory system is one of the most accessible organs for diagnostic testing, it is not always easy to define respiratory diseases in horses. In mature horses results of physical examination can be difficult to interpret accurately and although pertinent ancillary diagnostic modalities can help further characterize and localize causes for respiratory dysfunction, in most cases, however the findings are not specific. Early recognition of respiratory abnormalities during the postnatal period is of special importance for successful management of critically ill foals. In most foals, physical examination is not adequate for precise identification of the cause or severity of respiratory dysfunction, even when clinical signs are present. Clinical signs have to be interpreted in conjunction with clinicopathologic and diagnostic imaging findings.
Diagnostic procedures performed by first opinion veterinarians in the field are often restricted to taking the history and performing clinical examination. Respiratory tract endoscopy, tracheal or bronchoalveolar lavage and blood sampling are sometimes used but other specific ancillary examinations are seldom performed in stable settings. Therefore, our objectives were to evaluate the diagnostic value of different techniques and examination types routinely used in the diagnostic workup of chronic equine lower airway cases in both stable and clinical circumstances. Another aim of this study was to estimate the prevalence of different chronic pulmonary disorders among horses admitted to a Hungarian referral clinic. According to the conditional inference tree method, age of the horse, history, clinical examination, respiratory tract endoscopy and bronchoalveolar lavage cytology proved to be the most valuable tools to define pathology. It was also concluded that in 22% of cases more specific ancillary diagnostic modalities, unavailable for the field veterinarian, were needed to establish the final diagnosis. According to our study, the most frequently diagnosed chronic pulmonary disorders in Hungary are of non-infectious origin, principally recurrent airway obstruction (RAO). Regardless of the cause, and interestingly including RAO as well, these diseases occur primary during the warm months.
Thoracic radiographs of foals made immediately after birth are characterized by a pronounced interstitial-alveolar opacity with blurring of small vessels. This opacity is the result of incomplete lung inflation, the presence of residual fluid in the small airways, and uptake of fetal alveolar fluid
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into the lung interstitium. Foals with respiratory disease may have a similar radiographic pattern, but it typically persists beyond the normal absorption time. In the second part of my thesis the kinetics of postnatal equine lung using sequential thoracic radiography was characterized. The aim was to establish the earliest time when normal foals have clear, radiolucent lung fields, and to characterize the pattern of this clearance. Both right-to-left and left-to-right thoracic radiographs were acquired in lateral recumbency at peak inspiration within the first 30 min after birth and thereafter at 1, 2, 3, 4, 6, 8, 12, 24, 48, and 72 h. Radiographs were interpreted by three observers. The overall assessment of radiographic lung clearance was followed by the evaluation of individual lung quadrants to document changes in pulmonary radiographic patterns over time. It was concluded that thoracic images in a healthy foal older than 4 h should be characterized by clear lungfields and after this period distinctions between physiologic and pathologic conditions can be made. The ventral lung cleared first, presumably due to the greater flexibility of the thoracic wall in this anatomic region. | en |
