Pituitary gland abscess in a horse subsequent to head trauma

A 5-year-old Thoroughbred gelding with recent history of head trauma presented with multiple facial swellings, bilateral mucopurulent nasal discharge, neck pain, inappetence and depression. On computed tomographic examination, lesions within the pituitary fossa and structures adjacent to the right guttural pouch were identified. Soft tissue swelling was seen in the dorsal aspect of the right guttural pouch surrounding several cranial nerves, with fluid-like material in the dependent portions of the right guttural pouch. A CSF sample revealed mild mixed pleocytosis and increased protein concentration. The horse had concurrent periapical disease of the 209-cheek tooth and mild left sinusitis. The horse's demeanour deteriorated requiring euthanasia. Post-mortem examination revealed a pituitary gland abscess.     

Ocular changes in a horse with gutturomycosis.

Recurrent epistaxis and locomotor and visual disturbances leading to blindness in a 7-year-old gelding appeared to have resulted from a spreading fungal granuloma of the guttural pouch. The inflammatory area extended to the intracranial segment of the right optic nerve and to the region adjacent to the optic chiasma. Microscopically, changes indicative of multiple foci of ischemic infarction were noticed in the retina, optic nerves, optic chiasma, and optic lobe. The profusely growing fungal elements in the guttural granuloma had the morphologic characteristics of an Aspergillus sp.     

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.     

Fistula between the guttural pouches and the dorsal pharyngeal recess as a sequela to guttural pouch mycosis in the horse

An unusual case of a two year old gelding with severe unilateral epistaxis due to guttural pouch mycosis is reported. The lesion had spread to involve the dorso-medial aspects of the right guttural pouch and had formed a fistula between the dorsal pharyngeal recess and both the left and right guttural pouches. The diagnosis, surgical treatment and postoperative management are described.     

Primary distension of the guttural pouch lateral compartment secondary to empyema

A 6-year-old, 420-kg quarter horse gelding was presented with a 2-month history of difficulty swallowing and dyspnea. The horse was diagnosed with a right guttural pouch empyema with many large chondroids. Two surgeries were required to completely remove all the chondroids from what proved to be a primary distension of the guttural pouch lateral compartment.     

Complications of Balloon Catheterization Associated With Aberrant Cerebral Arterial Anatomy in a Horse With Guttural Pouch Mycosis

A 3-year-old Quarter Horse gelding was treated for left guttural pouch mycosis by ligation and balloon catheterization of the left internal carotid artery. Catheter advancement was shorter (10 cm) than the normally reported distance (13–15 cm), but was observed endoscopically during placement as it coursed within the internal carotid artery through the guttural pouch. The horse developed a persistently abnormal respiratory pattern after catheter placement, failed to gain consciousness, developed pulmonary edema, and died 5.5 hours postoperatively. Postmortem examination revelaed an aberrant left internal carotid arterial course with location of the embolectomy catheter at the junction of the basilar and caudal cerebellar arteries. Brainstem neuronal necrosis and alveolar and interstitial pulmonary edema were identified on histological examination. Angiography may be used to identify aberrant branching patterns. Failure to identify and occlude aberrant branches may result in fatal epistaxis and Brainstem lesions.     

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.

     

Equine rhabdomyolysis

A 1.5-year-old Quarter Horse gelding with a history of chronic nasal discharge and leukocytosis presented with signs of increased lethargy and muscular pain. The horse quickly became recumbent and unable to rise and was euthanized due to a poor prognosis. At necropsy, severe bilateral guttural pouch empyema was observed, as well as numerous well-demarcated areas of pallor within the skeletal muscles of all major muscle groups. Polymerase chain reaction testing of the guttural pouch exudate confirmed an infection with Streptococcus equi subsp. equi, and an S. equi-associated immune-mediated rhabdomyolysis was initially considered to be the most likely diagnosis. This report briefly discusses the various etiologies that should be considered in cases of equine myopathy, and it demonstrates the complexity of these poorly understood muscular disorders.     

Traumatic bilateral stylohyoid bone fracture in an Appaloosa

An Appaloosa gelding presented for a traumatic puncture wound of the head ventral to the base of his left ear, bilateral epistaxis and upper respiratory compromise. The horse did not exhibit dysphagia or cranial nerve deficits. The horse suffered bilateral oblique fractures of both stylohyoid bones due to the traumatic incident, diagnosed upon endoscopy of the guttural pouches. Treatment consisted of anti‐inflammatory medication, broad‐spectrum antibiotics, guttural pouch lavage and dietary management with soft feeds. At a one‐month follow‐up examination, endoscopic evaluation revealed a union at both stylohyoid bone fracture sites. Guttural pouch mycosis was diagnosed in the left guttural pouch on the lateral wall at the entrance of the lateral compartment. The guttural pouch mycosis was treated with a nystatin and gentamicin flush, followed by a course of oral fluconazole. At the 3‐month re‐evaluation, the guttural pouch mycosis had completely responded to treatment.     

Progression of mycosis of the auditory tube diverticulum (guttural pouch) after arterial occlusion in a horse with contralateral temporohyoid osteoarthropathy

CASE DESCRIPTION: A 6-year-old Appaloosa mare was examined because of inappetance, difficulty eating, and swelling and mucopurulent discharge in the right eye. CLINICAL FINDINGS: Results of a CBC and serum bio-chemical analysis revealed no important findings. Ophthalmologic examination revealed scarring and ulceration of the superficial layers of the cornea. Endoscopic examination of the upper portion of the respiratory tract and auditory tube diverticula (guttural pouches) revealed abnormal thickness of the right stylohyoid bone and a plaque suggestive of mycotic growth on the left internal carotid artery. Radiographic examination revealed right-sided otitis media. Temporohyoid osteoarthropathy in the right guttural pouch and mycosis in the left guttural pouch were diagnosed. TREATMENT AND OUTCOME: Ceratohyoidectomy of the right stylohyoid bone was performed, and the left internal carotid artery was occluded via placement of stainless steel spring embolization coils. The mare regained the ability to eat without difficulty and improved clinically for approximately 4 weeks. However, the mare returned to the medical center 53 days after surgery with left-sided Horner syndrome, atrophy of the right side of the tongue, and a 3-week history of dysphagia and weight loss. Endoscopic evaluation revealed progression of mycotic growth in the left guttural pouch. The mare was euthanatized. CLINICAL RELEVANCE: Although the mycotic lesion in the left guttural pouch was an incidental finding at the time of initial examination, the lesion progressed to cause dysphagia and Horner syndrome after occlusion of the left internal carotid artery, a treatment that is typically associated with resolution of guttural pouch mycosis. Arterial occlusion is not necessarily a reliable method of resolving guttural pouch mycosis.     

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.     

Malignant melanoma in a grey horse: case presentation and review of equine melanoma treatment options

A 15 year-old grey Thoroughbred gelding presented for investigation of chronic weight loss and recent onset of respiratory difficulty. Clinical examination confirmed tachypnoea with increased respiratory effort. Thoracic ultrasound examination detected pleural effusion. The dyspnoea was related to the large volume of pleural effusion and, following post-mortem examination, to the presence of a large mediastinal mass. Multiple pigmented masses, likely melanomas, were detected peri-anally. Thoracic radiography, cytological examination of the pleural fluid and a fine needle aspirate of a thoracic mass led to a presumptive diagnosis of malignant melanoma and this was confirmed at post mortem examination. Further metastatic spread to the central nervous system and right guttural pouch was also identified. In conclusion this case manifests the potential malignant behaviour of equine melanomas, and a review of proposed therapies for melanoma treatment highlights the therapeutic options and current areas of research.     

Laser fenestration of the mesial septum for treatment of guttural pouch chondroids in a pony

OBJECTIVE: To describe removal of guttural pouch chondroids through a laser fenestrated mesial septum in a pony with an obstructed pharyngeal ostium of the left guttural pouch. STUDY DESIGN: Case report. ANIMALS: Pony. METHODS: Transendoscopic laser neodymium:yttrium aluminum garnet (Nd:YAG) fenestration of the mesial guttural pouch septum was made by contact method (bare fiber, 15-25 W, exposure time 4 seconds). Dissected tissue was removed by transendoscopic monopolar electrosurgery (loop electrode, cutting blade) and multiple chondroids of varying size were removed from the left guttural pouch through the fenestration. RESULTS: After removing all chondroids and repeated flushing of the left guttural pouch via the right side, inflammation of the guttural pouch membranes decreased remarkably. The pony was discharged with instructions for transendoscopic lavage once weekly and was reevaluated at 2 months. A permanent septal fenestration was observed and the pony was free of abnormal clinical signs and being used for carriage driving competitions. CONCLUSION: Nd:YAG laser fenestration of the mesial septum is an approach for access to guttural pouch chondroids. CLINICAL RELEVANCE: When guttural pouch empyema and/or chondroids is associated with adhesion of the pharyngeal ostium, laser fenestration of the mesial septum from the opposite guttural pouch should be considered as an alternative approach for access, rather than classic external surgical approaches.     

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.     

Immune-mediated hemolytic anemia associated with trimethoprim-sulphamethoxazole administration in a horse.

A 10-year-old, thoroughbred gelding was administered sulphonamide drugs during surgical treatment of guttural pouch mycosis. The horse became anemic and a diagnosis of immune-mediated hemolytic anemia was made after other causes of anemia had been ruled out. The anemia resolved after the drugs were withdrawn.     

Successful treatment of hyperkalaemic periodic paralysis in a horse during isoflurane anaesthesia

HistoryA 3-year-old, 400 kg, gelding Quarter Horse was presented for investigation of epistaxis.Physical examinationThe horse was bright, alert and responsive with rectal temperature, heart rate and respiration rate within normal limits.ManagementDuring a second general anaesthetic for surgical treatment of guttural pouch mycosis by balloon-tipped catheter occlusion of the right major palatine artery and ligation of the right external carotid artery, signs consistent with hyperkalaemic periodic paralysis (HYPP) were exhibited. These included concurrent hyperkalaemia, hypercapnoea, sinus tachycardia, and muscle fasciculations in the presence of normothermia. Stress associated with an acute haemorrhage pre-operatively, and intra-operative hypercapnoea may have precipitated the episode. There were no signs of HYPP during a general anaesthetic, 1 week earlier, when an initial attempt at surgical treatment of guttural pouch mycosis was performed. Treatment consisted of fluid therapy and administration of calcium gluconate (0.1–0.2 mg kg^?1 minute^?1), dextrose 5% (5 mL kg^?1 hour^?1) and insulin (0.05 IU kg^?1). Treatment resulted in the resolution of clinical signs and an uneventful recovery.Follow-upThe diagnosis of HYPP was confirmed by DNA analysis post-operatively.ConclusionsClinical cases of intra-operative HYPP can present despite a previous history of uneventful general anaesthesia. Rapid diagnosis and treatment can result in the successful management of HYPP. This report documents an unusual presentation of HYPP, a disease that remains present in the Quarter Horse population.     

Dysphagia caused by focal guttural pouch mycosis: mononeuropathy of the pharyngeal ramus of the vagal nerve in a 20-year-old pony mare

A 20-year-old pony mare was presented to the equine hospital with a ten-day history of dysphagia, regurgitation and coughing. An obstruction of the oesophagus was excluded via endoscopy, but the proximal oesophagus appeared to be distended and circular contractions were missing. A guttural pouch endoscopy revealed a single, black-mottled plaque on the pharyngeal ramus of the vagus nerve in the left guttural pouch, causing a local swelling of this nerve. The pharyngeal ramus seemed to be atrophic distal to the lesion. A biopsy was taken from the lesion and histopathological findings proved the reasonable suspicion of a guttural pouch mycosis with a high degree of purulent-necrotic inflammation and invasion of fungal hyphae. There were no signs of neoplasia, such as melanoma. Daily guttural pouch irrigations with a clotrimazole emulsion (20 g Canesten^® Gyn⁴ solved in 500 ml water), led to a good recovery of the mucosa above the nerve. Periodic endoscopic examination of the left guttural pouch showed that local thickening and distal atrophy of this pharyngeal ramus did not improve, neither did the clinical symptoms. Due to progressive weight loss, acute respiratory distress and aspiration pneumonia, the 20-year-old pony mare unfortunately had to be euthanized three weeks after discharge. This case report emphasizes the enormous importance of a single nerve for the realization of the swallowing process. The one-sided loss of function of the pharyngeal branch of the vagal nerve cannot be compensated neither by the remaining ipsilateral nerves nor by the contralateral normal functioning glossopharyngeal and vagal nerves and thus inevitably leads to severe dysphagia.     

Soft tissue sarcomas in the pharyngeal region of a 5‐year‐old Quarter Horse mare

This case report describes the identification of multiple soft tissue sarcomas in the pharyngeal region of a 5‐year‐old Quarter Horse mare. Diagnostic work‐up included physical examination, radiography, ultrasonography, endoscopic examination of upper airways and guttural pouch, and post mortem examination with histopathology. Humane euthanasia was indicated due to the chronicity of the condition, prognosis and financial constraints.     

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.     

Functional anatomy observations of the pharyngeal orificeof the equine guttural pouch (Auditory tube diverticulum)

The pharyngeal orifice of the equine auditory tube has not been adequately described. Its larger size andposition, further rostral within the nasopharynx compared with other species, cannot be easily explained, but could be important for the proposed brain-cooling function of the guttural pouches; however, unlike other species, it may not be the sole regulator of auditory tube aeration. A ‘second orifice’ (representing the final entrance to the auditory tube diverticulum) deserves recognition in performing a role in air exchange between the auditory tube, diverticulum and middle ear. The results of this investigation suggest that regular guttural pouch ventilation during resting respiration does not occur. Previous reports may reflect, at least in part, a misinterpretation of air pressure measurements within the guttural pouches and nasopharynx. Small decreases in simulated inspiratory pressure consistently caused the passive opening of both the pharyngeal orifice and pouch ostium in horse cadavers suggesting that an active counter process may exist in the live horse to maintain closure of the guttural pouch openings during rest and light exercise. Intrinsic tone of the stylopharyngeus and pterygopharyngeus muscles may be part of this active process. The investigation offers theoretical evidence that opening of the equine auditory tubes to ventilate the guttural pouch occurs in two different ways, active and passive. The active process has two stages: (1) opening of the pharyngeal orifices by simultaneous contractions of the levator and tensor veli palatini, and pterygopharyngeus muscles; then (2) opening of the pouchostia by contractions of dorsal portions of the palatopharyngeus muscles. The alternative passive route involves reduction in tone of the stylopharyngeus and pterygopharyngeus muscles accompanied by increased inspiratory pressure.