Left and Right Laryngeal Hemiplegia in horses

The endoscopic images below are from two different horses with similar clinical complaints yet slightly different physical problems. The gelding in Figure 1 presented for significant respiratory noise during the canter (roaring) and resistance when cantering to the right. The gelding was 12 years old and had a history of "roaring" for multiple years.  In Figure 1, it is evident that there is complete paralysis of the left arytenoid process. Under exercise, the paralyzed process tended to cross over mid-line and prevent adequate passage of air.  He was referred to a surgical facility and a "tie back" procedure was performed. Thirty day post-op endoscopy revealed near complete abduction of the left arytenoid (Figure 2)!! The gelding is significantly improved and will likely perform at a higher level than that prior to surgery.

Figure 1

Figure 2

The endoscopic images in Figure 3 and 4 were from a gelding that presented for significant exercise intolerance at the canter in either direction. The initial endoscopic exam revealed complete paralysis of the right arytenoid process (Figure 3). Paralysis of the right arytenoid is much less common than paralysis of the left arytenoid process and is associated with a worse prognosis. Consultation with an equine surgeon determined that the gelding was NOT a candidate for a "tie back" procedure. In an attempt to improve the gelding's airway, a surgical ablation of several components of the larynx was performed. The thirty day post-op endoscopy revealed a significantly improved airway (Figure 4). Prognosis for this horse as a sport horse remains to be determined however his quality of life has significantly improved! These two cases demonstrate the importance of acquiring the correct diagnosis and surgical intervention via an experienced and highly skilled equine surgeon!! Thank you Dr. John Madison (Ocala Equine Hospital)

Figure 3

Figure 4

Severe Roaring in a Horse!!

A teen-age mare presented for respiratory noise during exercise and poor performance. The mare had made noise during exercise for the past 2-3 years WITHOUT poor performance. Interestingly, the mare has always been resistant when cantering to the RIGHT! Recently, it was noted that the mare demonstrated signs of exercise intolerance at the canter. During the exam, the mare was asked to canter on a lunge line and she carried her head to the outside of the circle with her nose turned up. After 1-2 minutes of cantering to the right, it became increasingly more difficult for her to catch her breath and she would occasionally cough/gag violently!. 

Figure 1

 The mare was scoped immediately after exercise and complete paralysis of the left arytenoid was discovered (Figures 1-2). During inspiration, the left arytenoid was across mid-line (yellow line) and obstructing at least 50% of the mare's airway (Figure 2).  It is highly likely that during heavy exercise, the increased negative pressure during inspiration would cause the paralyzed arytenoid to completely cover the airway and prevent the mare from breathing! 

Figure 2

In addition, while scoping the horse, the mare tended to displace her soft palate in such a position that the epiglottis was trapped below (Figures 3-4). When this occurred, the mare instantly began to cough/gag until she corrected the displacement! Displacement of the soft palate is not always associated with arytenoid hemipligia but when it does occur may worsen the exercise intolerance.

Figure 3

The prognosis for this mare is dependent on additional evaluation by an equine surgeon and the recommended surgical procedure. If she is a good candidate for surgery and the surgery is a success, there is a good likelihood that she will return to work and perform significantly better than before.

Resolved Aspiration Pneumonia

Approximately 2 months ago a young warm blood gelding presented for a 4-6 month history of chronic coughing, bilateral nasal discharge, poly-synovitis, and failure to thrive. At presentation, the gelding was in poor body condition and there was a moderate amount of nasal discharge which consisted of mucus mixed with feed/hay. Auscultation of the thorax noted abnormal lung sounds, bilaterally.  As I reported previously, endoscopic exam revealed feed material within the larynx and trachea (Figure 1 and 2). The feed material was noted through out the entire trachea and a trans-tracheal wash revealed the presence of feed material and bacteria in the cranial ventral lung lobes! The gelding was diagnosed with dysphagia and aspiration pneumonia.

Figure 1

Figure 2

Based on the trans-tracheal culture results the gelding was treated with oral antibiotics for 30 days. In addition, he was treated with systemic anti-inflammatory medication and systemic anti-arthritic medication. Once the antibiotic treatment was started, the coughing episodes subsided but were not completely abolished. The gelding began to gain weight and for the first time was seen laying down to sleep and roll in the pasture! A follow-up endoscopy performed at the end of 30 days of antibiotics revealed feed material within the larynx (Figure 3) and an intermittent dorsal displacement of the soft palate (Figure 4). Mild to moderate ulcerations were noted along the caudal edge of the soft palate when displaced. At this point, we were not sure what was going to happen once we stopped treating with antibiotics however based on the continued presence of feed material in the pharynx, it was assumed that a recurrence of aspiration pneumonia was soon to follow.

Figure 3

After discussing the limited options with the owner, it was decided to pursue acupuncture as a potential source of treatment. Dr. Marilyn Maler was asked to examine the gelding and provide her expert opinion and treatment options. She immediately instituted an acupuncture regiment that was directed at treating the horse's difficulty with swallowing among other points of interest. According to the owner, the gelding's cough improved significantly and in a short period of time was completely absent! The gelding continued to gain weight and has been eating "normally" for over 4 weeks. A follow-up exam was performed 2 days ago and the gelding's condition has improved so dramatically that I did not even recognize the horse!  Endoscopic exam noted NO feed material in the pharynx and normal lung sounds!! The gelding has a long way to go but our conversation has shifted from when might it be time to "do the humane thing" to when might it be time to ride him!!  This case is a strong reminder of the benefits of acupuncture for treating chronic diseases and I wish to extend a special thanks to Dr. Maler for all her help!!

Figure 4

Final note: On the day of the most recent exam, the gelding was feeling so good that he played hard to get. So, he was enticed with several hand fulls of feed just prior to the endoscopic exam. This happens to be a crude method of detecting dysphagia in horses and the gelding passed with flying colors!!

Figure 5

Dysphagia and Aspiration Pneumonia in a horse!!

The endoscopy images below were from a young gelding that presented for a history of coughing while eating. In addition, an intermittent nasal discharge was present and the gelding was described as a "hard keeper". In Figure 1, a small amount of feed material was noted along the floor of the soft palate, just in front of the epiglottis. In addition, feed particles were noted on the epiglottis and the walls of the pharynx. These findings alone are not 100% indicative of a dysphagic (difficulty swallowing) horse however, generally speaking there should NOT be any feed material in the pharynx or larynx. 

Figure 1

When the endoscope was passed through the larynx into the trachea (wind pipe) copious amounts of feed material mixed with mucus was noted on the walls of the trachea. In Figure 2, green and brown feed material  can be seen adhered to the wall of the trachea. As the endoscope was pass further down the trachea, feed material mixed with mucus remained present in significant amounts. 

Figure 2

At the very end or deepest region of this image (Figure 3) is the primary bifurcation of the trachea which occurs just in front of the heart. The presence of feed material at this level of the airway is consistent with aspiration and a trans-tracheal wash was performed to confirm pneumonia.  

Figure 3

Dysphagia and aspiration pneumonia are quite uncommon in horses and may be secondary to a neuropathy affecting the nerves that control the swallow reflex. The most common disease processes in horses that may affect these nerves include equine protozoal myeloencephalitis (EPM), cervical spine trauma, trauma to the guttural pouches, temporohyoid osteopathy (THO), strangles, encephalitis, and basisphenoid bone fracture. Unfortunately, the prognosis is poor for horses with this condition. The likelihood that they will recover their normal swallow reflex, regardless of the cause, is low!  In addition, the aspiration pneumonia that results from the dysphagia  is a recurring problem that typically results in their failure to thrive!