Guttural pouch mycosis in two horses

The history and clinical findings of 1 horses with guttural pouch mycosis referred to us are described. The salient features of the history and clinical signs common to both cases were profuse spontaneous nasal haemorrhage, partial pharyngeal paralysis; subsequently bilateral nasal discharge containing food material, inability to drink and parotid pain became evident. One case made a gradual recovery with conservative medical treatment while the second case was destroyed and submitted for post-mortem, histopathological and microbiological examination. This examination failed to establish the initiating cause of the lesion but later stages were clearly associated with an invasive septate fungus morphologically resembling Aspergillus.     

Guttural pouch mycosis in a 6-month-old filly

A 6-month-old filly was presented with unilateral epistaxis. Based on clinical signs, endoscopic examination, and postmortem examination, guttural pouch mycosis was diagnosed. The young age of the filly and the fact that this was the 2nd diagnosis of guttural pouch mycosis on this farm was unusual.     

Guttural pouch perforation caused during nasogastric intubation

A 19‐year‐old gelding presented with swelling of the pharyngeal region following evaluation for an episode of colic. Endoscopy, radiography and ultrasonography were utilised in diagnosis of a guttural pouch perforation, secondary to nasogastric intubation. Conservative treatment resulted in a fibrin seal over the perforation. Unfortunately, the horse succumbed to colitis and was subjected to euthanasia before resolution of the injury.     

Guttural pouch leiomyosarcoma causing nasopharyngeal compression in a pony

A 14‐year‐old Connemara cross gelding presented with abnormal respiratory noise and exercise intolerance. Upper airway endoscopy, ultrasonography, radiography and computed tomography revealed a large mass within the left guttural pouch causing marked left dorsal nasopharyngeal collapse and displacement and compression of the right guttural pouch. The horse was subjected to euthanasia and a post‐mortem examination confirmed the above findings. Histological and immunohistochemical examinations of the mass confirmed a diagnosis of guttural pouch leiomyosarcoma, a lesion previously unreported at this site.     

Guttural pouch empyema secondary to a periocular foreign body

This report describes a 3‐year‐old gelding presenting with signs of injury to its left eye following an accident in which the horse crashed into a hedge. The first treatment attempted to treat infections in the eye and respiratory tract due to secretions identified in the trachea. The horse did not improve and further clinical and radiographic evaluations detected a guttural pouch empyema. Surgical drainage was performed and antimicrobial treatment continued. However, the horse presented with severe epistaxis and euthanasia was elected due to suspected arterial rupture. At necropsy, a round and stiff branch plant was found creating a fistula from the left orbit to the left guttural pouch. Another branch was found inside the pouch, confirming the origin of the persistent infection and severity of the tissue lesion.     

Treatment of guttural pouch mycosis

Seventeen cases of guttural pouch mycosis (including two bilaterally affected cases) were diagnosed in a three year period. The presenting signs were, in order of frequency, epistaxis at rest, nasal catarrh, pharyngeal paralysis, ipsilateral laryngeal hemiplegia, swelling of the submandibular/parotid region, extension of the head and neck and dyspnoea. Ligation of the origin of the internal carotid and occipital arteries was attempted in 10 of the cases exhibiting epistaxis. Bilateral ligation was performed on one animal with an untoward sequelae. Where surgery was successfully completed further haemorrhage was prevented in eight out of nine affected pouches (89 per cent). Medical treatment involving local administration of various antifungal preparations via a specially designed catheter and/or the oral administration of benzimidazole drugs was successful in eliminating the mycotic plaque in most cases. Cases which presented with pharyngeal paralysis were all fatal.     

Guttural pouch empyema caused by Corynebacterium pseudotuberculosis in a pregnant mare

During medical management of mild colic in a 12‐year‐old Quarter Horse, mid‐gestation mare, unilateral purulent nasal discharge from the right nostril was noted. Endoscopic examination revealed guttural pouch empyema. Culture was positive for Corynebacterium pseudotuberculosis and negative for Streptococcus equi ssp. equi. A synergistic haemolysis inhibition titre of 1024 was consistent with C. pseudotuberculosis infection. Treatment included serial lavages and local infusion of antibiotics into the guttural pouches along with a 6‐week course of oral trimethoprim–sulfamethoxazole and rifampicin. Overall, no additional sites of infection were identified and the mare responded well to treatment, delivering a healthy, full‐term foal. This case emphasises that C. pseudotuberculosis, although uncommon, should be considered as a differential for guttural pouch empyema.     

Guttural pouch hemorrhage associated with lesions of the maxillary artery in two horses

A two year old Thoroughbred gelding, presented with guttural pouch hemorrhage, had the internal and external carotid arteries ligated. Guttural pouch mycosis was detected on endoscopic examination. After one month of topical antifungal therapy, the horse was returned and euthanized because of recurrent epistaxis. A bacterial infection of the guttural pouch with associated ulceration and hemorrhage from the maxillary artery was found at necropsy.

A two year old grade gelding had ulceration and hemorrhage from the external carotid artery. Utilizing balloon-tipped catheters and arterial ligation, hemestasis was achieved in the internal carotid artery and the external carotid artery and its branches. Mycotic ulceration of the internal carotid artery was detected endoscopically and treated with local antifungal therapy for one month. Thirty-three days postoperatively the horse returned, bleeding from a lesion in the maxillary artery. The rationale for surgical intervention to prevent epistaxis associated with guttural pouch mycosis and possible etiologies for postsurgical epistaxis are discussed.

     

A case of guttural pouch mycosis in a horse

A case of guttural pouch mycosis in an 11-year-old horse is described. The fungus isolated was identified as Emericella nidulans. Housing under bad hygienic conditions without ventilation for three years might have been a predisposing factor.     

Gutteral pouch mycosis and mycotic encephalitis in a horse

A case of mycotic encephalitis in a horse with guttural pouch mycosis is described. A liquid pellet feed binder contaminated with Aspergillus sp. and erroneously mixed in a feed concentrate was a possible source of infection.     

Outcome of treatment in 35 cases of guttural pouch mycosis

This paper describes the outcome of treatment of 30 cases of guttural pouch mycosis by ligation of the internal carotid artery on the cardiac side of the lesion and lavage of the affected pouch with natamycin. Twenty-three horses recovered fully following this treatment while laryngeal hemiplegia persisted in one case and slight dysphagia caused by pharyngeal hemiplegia in another. The remaining five horses died or were destroyed. Five horses with guttural pouch mycosis, which had shown no epistaxis but had pharyngeal hemiplegia, were treated by topical natamycin alone. Only two of these survived, of which one remained slightly dysphagic. Ligation of the internal carotid artery of the cardiac side of the lesion is an effective means of reducing the chance of fatal epistaxis in cases of guttural pouch mycosis. Some cases of pharyngeal hemiplegia can make a complete recovery although it may take 12 to 18 months.     

Suspected retropharyngeal haemorrhage as a complication of guttural pouch mycosis

An 11-year-old Thoroughbred mare presented for evaluation of severe, acute bilateral epistaxis of several hours’ duration. Endoscopic evaluation revealed active haemorrhage from the right guttural pouch and significant dorsal compression of the nasopharynx. Rapid and severe retropharyngeal swelling developed, prompting placement of a temporary tracheostomy. Guttural pouch mycosis was suspected and transarterial coil embolisation of the right internal carotid, external carotid and maxillary arteries was successfully performed. It was suspected that haemorrhage from the vasculature of the guttural pouch tracked caudally into the retropharyngeal region resulting in significant swelling, pharyngeal collapse and a severely compromised airway. Clinicians should be aware of this rare complication of guttural pouch epistaxis.