Association of owner-reported noise with findings during dynamic respiratory endoscopy in Thoroughbred racehorses.
Authors: Witte S H P, Witte T H, Harriss F, Kelly G, Pollock P
Journal: Equine veterinary journal
Summary
# Editorial Summary Owner-reported respiratory noise in racehorses is a poor predictor of specific upper airway pathology, despite being a common reason for clinical investigation. Witte and colleagues performed dynamic respiratory endoscopy (DRE) on 85 Thoroughbreds presented for abnormal respiratory noise and/or poor performance, examining the strength of association between the sounds owners describe and actual anatomical or functional abnormalities identified during exercise. Whilst 82% of horses presented for noise complaints did have one or more obstructive conditions on DRE, the relationship between noise type and diagnosis was frequently misleading: 48% of horses described as making guttural, rattling or rough sounds had isolated soft palate dysfunction, but a further 24% had palatal dysfunction combined with other abnormalities; amongst horses with a history of whistling or roaring (suggesting laryngeal disease), only 27% had recurrent laryngeal neuropathy as a sole finding, whilst 40% presented with vocal cord collapse alongside additional pathology. The sensitivity of abnormal noise for detecting upper respiratory obstruction was high (84%), but specificity was poor (25%), and whilst whistling and roaring showed good specificity for laryngeal dysfunction (≥80%), characteristic noise patterns had only moderate to low sensitivity for specific conditions. For practitioners, these findings emphasise that clinical diagnosis based on owner observations and performance history alone risks missing complex, multi-site upper airway disease; DRE should be regarded as essential rather than confirmatory in horses with reported respiratory noise to establish complete diagnoses and appropriate treatment strategies.
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Practical Takeaways
- •Do not rely on owner-reported noise patterns alone to diagnose specific upper respiratory conditions—many horses with abnormal noise have complex, multifactorial obstructions that require DRE to identify completely
- •Perform dynamic respiratory endoscopy in all racehorses presenting with abnormal respiratory noise, even if the noise pattern seems characteristic, to avoid missing concurrent conditions that may affect performance
- •While whistling and roaring are reasonably specific for laryngeal pathology, gurgling and rattling are non-specific markers that commonly indicate palatal dysfunction but frequently coexist with other obstructions
Key Findings
- •82% of 85 horses with abnormal respiratory noise had one or more obstructive upper respiratory tract abnormalities on dynamic respiratory endoscopy
- •48% of horses reported to gurgle, rattle or make rough noise were diagnosed with solitary palatal dysfunction, with 24% having palatal dysfunction combined with another abnormality
- •27% of horses with whistling or roaring history showed recurrent laryngeal neuropathy; 7% had vocal cord collapse alone and 40% had vocal cord collapse with another abnormality
- •Owner-reported noise had high sensitivity (84%) but low specificity (25%) for any upper respiratory obstruction; whistling and roaring showed highest specificity (≥80%) for laryngeal dysfunction