Equine laryngeal hemiplegia part II: Some clinical observations.

The research article discusses the clinical characteristics observed in horses suffering from equine laryngeal hemiplegia, a common cause of abnormal respiratory noise in horses. It details the onset of symptoms, associated health anomalies found, and the outcome of medical examinations.

Findings and Observations

• The study is based on the observation of 127 horses diagnosed with laryngeal hemiplegia. The onset of symptoms in these horses varied, with some displaying sudden onset while others showed insidious development of the condition.
• The common reason for these cases being brought to attention was an abnormal noise during respiration, particularly when exercising. There were other clinical signs observed, some of which were similar to laryngopalatal dislocation, a condition where the larynx and soft palate do not coordinate properly.
• The left arytenoid was affected in all examined cases. In three horses, however, bilateral laryngeal dysfunction was noted, indicating the presence of the disorder in both the left and right arytenoids.

Investigations and Associated Anomalies

• In-depth examination of 65 animals using a fiber-optic endoscope revealed the presence of other upper respiratory tract abnormalities along with abnormal arytenoid movements in 30 horses. This points to the likelihood of concurrent health issues when laryngeal hemiplegia is present.
• Despite the severity of the condition, electrocardiograms (EKGs) of 45 affected horses did not show a significantly greater incidence of abnormalities compared to the general horse racing population. This halts any association of laryngeal hemiplegia with cardiac conditions.
• In the majority of the hemograms (blood tests) conducted on the affected horses, results were within normal limits, implying that the horses were otherwise healthy, and laryngeal hemiplegia didn’t appear to interfere with their overall health condition.

Limitations and Conclusions

• Interestingly, the study could identify possible causes of the condition in only 11% of the affected horses. This shows a considerable gap in understanding the etiology of this disorder, indicating the need for more focused research.