How do you diagnose equine asthma? (its gold standard)

• A. BAL
• B. Endoscopy
• C. Radiography
• D. CT

Answer: (A)

The main concept is that directly sampling the lower airways to look for inflammation provides definitive evidence for equine asthma. Bronchoalveolar lavage cytology is the gold standard because it collects fluid from the distal airways and lets you see the actual inflammatory cells driving the disease. A BAL sample typically shows increased neutrophils in inflammatory airway disease, with possible eosinophils or mast cells depending on the phenotype. This cellular picture confirms asthma and helps gauge severity, something imaging or endoscopy alone cannot provide. Endoscopy can reveal mucus and mucosal changes but doesn’t prove lower-airway inflammation. Radiography and CT may show secondary structural changes, but they don’t offer the direct cellular evidence that BAL cytology does.