Clinic for Horses, University of Veterinary Medicine Hannover, Foundation, Bünteweg 9, 30559, Hannover, Germany.
Institute of Biochemistry, University of Veterinary Medicine Hannover, Foundation, Bünteweg 17, 30559, Hannover, Germany.
Acta Vet Scand. 2024 Sep 18;66(1):51. doi: 10.1186/s13028-024-00773-7.
Equine asthma is a common, non-infectious, chronic lung disease that affects up to 80% of the horse population. Strict phenotyping and identification of subclinically asthmatic horses can be challenging. The aim of this study was to describe equine asthma phenotypes (mild, moderate, and severe asthma) defined by BALF cytology and occurrence of clinical signs in a population of privately owned horses and to identify the variables and examination steps with best discriminative potential. The standardised examination protocol included clinical examinations, blood work, airway endoscopy with bronchoalveolar lavage fluid analysis, arterial blood gas analysis and radiography under clinical conditions performed by one veterinarian.
Out of 26 horses, four were diagnosed with mild (subclinical), seven with moderate, and seven with severe asthma based on clinical examination and BALF cytology. Eight horses served as controls. Cough with history of coughing was the strongest variable in phenotype differentiation. Factor analysis revealed an increasing clinical variability with disease severity and an overlapping of clinical presentations between phenotypes. Elevated mast cell (4/4 horses) and neutrophil counts (3/4 horses) in bronchoalveolar lavage cytology differentiated mild asthmatic horses from healthy horses. Moderate and severe asthmatic horses were characterised by clinical signs and neutrophil counts.
The results indicate that medical history, clinical examination and bronchoalveolar lavage cytology are minimum indispensable steps to diagnose equine asthma and that phenotypes are clinically overlapping. A differentiation of three phenotypes without neutrophil and mast cell counts in bronchoalveolar lavage cytology is not sufficient for clinical diagnostics. A comparably exact diagnosis cannot be achieved by relying on alternative examinations used in this study. Screenings of inconspicuous horses with bronchoalveolar lavage can aid in diagnosing subclinically affected animals, however, group size was small, the procedure is invasive and clinical relevance of slightly elevated cells in bronchoalveolar lavage remains unclear. Clinical relevance could not be clarified in this study, since follow-up examinations or lung function testing were not performed.
马气喘病是一种常见的非传染性慢性肺部疾病，影响了多达 80%的马群。严格表型分析和亚临床气喘马的识别具有挑战性。本研究旨在描述通过 BALF 细胞学和临床症状在私人拥有的马匹中定义的马气喘病表型（轻度、中度和重度气喘），并确定具有最佳鉴别潜力的变量和检查步骤。标准化的检查方案包括临床检查、血液检查、气道内窥镜检查和支气管肺泡灌洗分析、动脉血气分析和放射学检查，由一名兽医在临床条件下进行。
在 26 匹马中，根据临床检查和 BALF 细胞学，有 4 匹马被诊断为轻度（亚临床）、7 匹马为中度和 7 匹马为重度气喘。8 匹马作为对照。有咳嗽史的咳嗽是表型差异的最强变量。因子分析显示，随着疾病严重程度的增加，临床变异性增加，表型之间的临床表现重叠。支气管肺泡灌洗细胞学中嗜酸性粒细胞（4/4 匹马）和中性粒细胞计数（3/4 匹马）升高可将轻度气喘马与健康马区分开来。中度和重度气喘马的特征是临床症状和中性粒细胞计数。
结果表明，病史、临床检查和支气管肺泡灌洗细胞学是诊断马气喘病的最低必需步骤，且表型在临床上有重叠。没有支气管肺泡灌洗中性粒细胞和嗜酸性粒细胞计数的三种表型的区分对于临床诊断来说是不够的。在本研究中使用的替代检查无法达到比较准确的诊断。支气管肺泡灌洗对无症状马匹的筛查有助于诊断亚临床受影响的动物，但组规模较小，该程序具有侵入性，支气管肺泡灌洗中稍高细胞的临床相关性尚不清楚。由于没有进行后续检查或肺功能测试，本研究无法明确其临床相关性。
