Recurrence of Pharyngeal Pythiosis in a Horse

The image in Figure 1 is that of a "normal" larynx and pharynx in a horse. In Figure 2-4, the pharynx is filled with granulomas that are nearly completely obstructing the larynx. The images in Figures 2-4 belong to a middle-aged quarter horse mare that has been treated several times over 2 years for pythiosis of the pharynx. After each treatment with systemic anti-fungal medication, the granulomas shrink in size and the hemorrhagic discharge stops (Figure 4) . However, once the medication stops, the granulomas slowly begin to re-grow and the discharge returns. The image in Figure 4 was taken approximately 12 months prior to Figures 2 and 3. Although the granulomas are present and there is some drainage, the over-all condition of the pharynx is better than what we see in Figures 2 and 3!

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Figure 2

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Figure 4

 The most likely scenario in this case is that the pythiosis pathogen resides within the granulomas and although they shrink and appear to become inactive, the pathogen persists. Once the medication is stopped, the pathogen is allowed to multiply and the granulomas grown unabated!  Pythiosis was once believed to be a fungi put is now described as an algae that lives in stagnant water throughout the southeastern United States. The pathogen gains access to the horse through small wounds in skin or mucosa. I have diagnosed pharyngeal pythiosis in over a dozen horses in the past 10 years. Every case has involved horses with access to free standing water and all have responded favorably to the systemic anti-fungal. The case imaged in the figures above has been refractory and proven difficult to completely resolve!!

Guttural Pouch Fungal Infection Resolved!!

Back in January, a gelding presented for a history of recurrent nasal discharge. Endoscopic exam revealed the presence of a fungal infection within one of the guttural pouches (Figures 1 and 2) . A bacterial and fungal culture was performed on fluid/debris collected from the pouch. The bacterial culture was negative however the fungal culture was positive for Cladosporium spp. This species of fungi is very common in the environment, especially in the presence of moist or wet wood. In humans, it is a big player in fungi induced allergies. Interestingly, this species of fungi has not been described in the guttural pouch of a horse previously!

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Figure 2

The gelding was treated with a specific anti-fungal medication given by mouth daily. After 4 weeks of treatment, there was a 50% reduction in the size of the fungal plaque and the degree of inflammation (Figures 3 and 4).

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Figure 4

After 2 months of treatment there has been complete resolution of the fungal infection and inflammation (Figures 5 and 6). The stylohyoid bone remains slightly thickened compared to the opposite stylohyoid bone (Figure 7) however this will like resolve over the next 3-6 months. This case is unusual in several ways. First, the species of fungi has not been described before in the guttural pouch of a horse, secondly, most guttural pouch fungal infections include bleeding (epistaxis) thirdly, there are few reports of successful treatment of guttural pouch fungal infections in horses with JUST systemic anti-fungals.

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Round Two!! Pharyngeal Phythiosis

Figure 1

The endoscopic image in Figure 1 is from a middle aged quarter horse that presented for abnormal noise during exercise. The entire pharynx is obstructed by multiple granulomas.  Initial biopsy results were consistent with pythiosis and the gelding was treated with systemic anti-fungal medication for several months. 

Figure 2

Recheck endoscopy after 45 days revealed a significant improvement (Figure 2) ; however, treatment was discontinued prematurely and a final endoscopy was not performed.

Figure 3

Over 1 year after the initial presentation, the abnormal noise returned along with bloody nasal discharge. The pale yellow nodules have increased in size and number. Multiple small yellow granuoles are noted through out the pharynx and there is evidence of mild bleeding. The horse will again be treated with systemic anti-fungal medication. A follow up exam to follow!!

Cleft Palate!

Image 1

The first two images are from a yearling thoroughbred that presented for a long history of nasal discharge, coughing while eating, and the presence of water exiting from nostrils while drinking. The filly had been treated with antibiotics prior to the exam. Endoscopic exam revealed a defect within the soft palate that extended nearly the entire length of the soft palate. In addition, the epiglottis was entrapped by the aryepigltottic fold. 

Image 2

 The defect within the soft palate is known as a "cleft palate" and most likely has been there since birth. Fortunately, this is a relative rare condition! Normally, the palate plays the role of separating the nasal passages from the oral passage. Hence, a horse is an obligate nasal breather and the palate keeps water and feed from entering the airway. When a cleft palate exists, there is communication between the air passage and oral passage resulting in feed and water going the "wrong way". This may consist of feed material exiting the nostril and/or traveling down the trachea into the lungs. If these horse go undiagnosed they are typically "poor doers" with failure to thrive secondary to chronic respiratory infections. Sadly, there is little to be done to help such a severe cleft palate. Less severe cases may be addressed with surgical intervention with mixed results. 

Image 3

The third image if that of a "normal" horse. The epiglottis is visible and is resting on top of the complete soft palate. Diagnosis of a cleft palate is often made immediately after birth during a thorough post-foaling exam. The veterinarian should palpate the length of the hard and soft palate with their finger to make sure it is normal. If missed at foaling, the diagnosis can be made quite simply with an endoscopic exam.