Endoscopic scoring of the tracheal septum in horses and its clinical relevance for the evaluation of lower airway health in horses.
Authors: Koch C, Straub R, Ramseyer A, Widmer A, Robinson N E, Gerber V
Journal: Equine veterinary journal
Summary
# Editorial Summary: Tracheal Septum Scoring and Lower Airway Assessment Whilst endoscopic evaluation of tracheal septum thickness has been adopted clinically to assess lower airway disease in horses, the Koch et al. study rigorously tested whether this measurement actually reflects meaningful pathology or inflammation. Using standardised endoscopic scoring, the researchers examined intra- and interobserver reliability, correlated septum thickness scores (STS) with established markers of airway inflammation (mucus accumulation, neutrophil counts in lavage fluid), compared affected and clinically normal horses, and assessed whether pharmacologically induced changes in breathing effort altered measurements. Although STS demonstrated excellent reproducibility within individual observers and acceptable consistency between different examiners, the critical finding was that STS failed to correlate with any established indicator of lower airway disease—including mucus scores, airway neutrophilia, and RAO status during both exacerbation and remission phases. Notably, older horses (≥10 years) showed significantly higher septum scores, suggesting age-related structural changes unrelated to active inflammation. For equine practitioners, this represents an important reality check: whilst tracheal septum endoscopy is technically reliable and reproducible, it should not be interpreted as a marker of lower airway inflammation or disease severity, and reliance on this measurement alone may lead to diagnostic error. Further validated diagnostic approaches remain essential for accurately assessing tracheobronchial health in clinical cases.
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Practical Takeaways
- •Tracheal septum thickness scoring by endoscopy is reproducible between observations, but should not be used as a standalone diagnostic indicator of lower airway disease or inflammation in clinical practice
- •Age-related increases in septum thickness occur independently of airway disease, so septum scores must be interpreted cautiously in horses ≥10 years old
- •Diagnosis of lower airway disease and inflammation should rely on other established clinical, endoscopic, and cytological findings (mucus accumulation, neutrophilia in secretions) rather than septum thickness alone
Key Findings
- •Endoscopic septum thickness scores showed excellent intra-observer and satisfactory inter-observer agreement, demonstrating reproducibility of the measurement technique
- •Septum thickness scores did not correlate with established clinical, endoscopic, and cytological indicators of lower airway inflammation including mucus accumulation and airway neutrophilia
- •Horses aged ≥10 years had significantly higher septum scores (P = 0.022) compared to younger horses, independent of airway disease status
- •Septum thickness scores did not differ significantly between clinically normal horses and those affected with recurrent airway obstruction in either exacerbation or remission phases