Diagnostic Approaches for the Assessment of Equine Chronic Pulmonary Disorders

Abstract

a b s t r a c tEven though the respiratory system is one of the most accessible organs for diagnostic testing, it is not always easy to define chronic lower airway disease in the horse. 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 noninfectious origin, principally recurrent airway obstruction. Regardless of the cause, and interestingly including recurrent airway obstruction as well, these diseases occur primarily during the warm months.

Analysis of Tracheal Secretion in Healthy Horses Undergoing a Vaquejada Simulation Test

“…History, clinical exam, endoscopy of the respiratory tract, and cytology of the tracheal lavage are valuable tools for investigating respiratory disease [24]. In the current study, we observed that, among these, cytology of the tracheal lavage is the most effective method for diagnosis, for there were no changes on physical exam, clinical history, or even endoscopy that would justify the cytology profile observed in these animals.…”

“…Although endoscopy is an easily performed exam, it is still little used routinely. In a previous study with 100 horses, 22 underwent endoscopy, of which 20 had a tracheal sample collected for cytology [24]. Endoscopy is the only method capable of identifying functional disorders of the upper respiratory tract [36] [37].…”

Recurrent airway obstruction: A review

“…In contrast to lung mechanics testing, endoscopic evaluation of the airways of horses presenting with respiratory disease is relatively commonplace in equine practice and is a principal diagnostic technique employed in the assessment of RAO cases. Visualisation of the tracheal lumen reveals an increase in tracheal mucus, a finding that has been shown to correlate with the presence of lower airway inflammation .…”

Advances in the Diagnosis of Equine Respiratory Diseases: A Review of Novel Imaging and Functional Techniques

“…An accurate characterization of the amount, location, and characteristics of pleural fluid or pleural thickening is easily obtained. Parenchymal lesions can be localized with high accuracy but often appear very similar and cannot be differentiated via an ultrasound examination [9]. During lung inflammation, the most common occurring artifact is comet tail, which can be detected in 91% of horses with equine asthma or exercise-induced pulmonary hemorrhage [10].…”