Pasteurella multocida isolation in a horse with retropharyngeal infection

Retropharyngeal infections in horses normally induce local painful swelling of the retropharyngeal area, which may lead to dyspnea, dysphagia, and systemic manifestations. Differential diagnosis of local painful swelling of the retropharyngeal area includes retropharyngeal lymph node infection, neoplasm, cellulitis, hematoma, guttural pouch empyema, parotiditis, and jugular thrombosis. Apart from Streptococcus equi ssp. equi, other bacteria are rarely reported as a cause of retropharyngeal abscesses. The reason for this might be a lack of specific sampling to identify the causative agent. This work deals with a case of retropharyngeal infection in an 11-year-old Standardbred stallion with acute depression, fever, tachycardia, asymmetric painful swelling in the throat area, ptyalism, and respiratory distress. Endoscopy, radiography, ultrasonography, blood analysis, and cytological examination of a puncture sample taken from the throat mass were consistent with a pyogenic to pyogranulomatous retropharyngeal inflammation. The clinical evolution was initially satisfactory in response to treatment with nonsteroidal anti-inflammatory drugs and antibiotics, but clinical signs relapsed twice, each time a few weeks after cessation of antibiotic therapy. The bacteriologic finding in this case was unusual and consisted of the isolation of a Pasteurella multocida strain that was obtained after the second relapse (ie, 79 days after initial admission), using a brain heart infusion (BHI) medium, and after two successive negative bacteriological cultures performed on day one of clinical signs and at the first relapse of clinical signs, respectively.     

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.     

PCR for antigen receptor rearrangement (PARR) clonality testing in a horse with a solitary retropharyngeal lymphoma

A 19-year-old Quarter Horse gelding was evaluated for respiratory distress and a rapidly enlarging retropharyngeal mass. Initial evaluation revealed severe respiratory distress, and a large, firm mass, visibly appreciable as 12 × 12 cm, in the left retropharyngeal and perilaryngeal region, with surrounding left and right retropharyngeal swelling. No significant abnormalities were present on complete blood count and serum biochemistry analyses. Endoscopy revealed severe pharyngeal collapse restricting airflow without gross abnormalities of the pharyngeal mucosa other than inflammation and irritation. A multilobular retropharyngeal mass, diffusely heterogeneous in echogenicity, was present adjacent to, but not occluding, the carotid artery as assessed by ultrasonography. Initial needle aspirate suggested lymphoma. Tissue biopsy and histopathology confirmed a round cell tumour. A temporary tracheotomy was performed to provide respiratory relief, and the horse was managed on oral antibiotics and anti-inflammatory medications while awaiting histopathological results. The decision was made to humanely euthanise the horse after biopsy results indicated lymphoma. Definitive diagnosis of T cell rich, large B cell lymphoma was made by combination of cytology, immunohistochemistry and molecular clonality PCR (PARR) testing. Lymphoma should be considered in horses with focal masses of the retropharyngeal region. Although treatment was not pursued, PARR testing was successful in this case and may be helpful for accurate characterisation of lymphoma in horses to more precisely determine prognosis and the most effective treatment plans, as it has been in human patients and small animals.     

Parotid salivary gland adenocarcinoma with bilateral ocular and osseous metastases in a dog

A case of primary parotid salivary gland adenocarcinoma is described in a three-year-old entire female great dane. The presenting complaint was sudden onset blindness concomitant with the development of bilateral hyphaema and anterior uveitis. A soft-tissue swelling of the left subaural region and right forelimb lameness were also present. A definitive diagnosis of primary parotid salivary gland adenocarcinoma with bilateral ocular metastases was made on post mortem examination. Metastases were also present in the right proximal humerus, left and right prescapular lymph nodes, left axillary lymph node, left retropharyngeal lymph node, bronchial lymph nodes and all lung lobes.     

Retropharyngeal lymph node infection in horses: 46 cases (1977–1992)

SUMMARY A retrospective study of 46 horses with retropharyngeal lymph node (RPLN) infection presented to the Rural Veterinary Centre between 1977 and 1992 was undertaken. Horses aged less than one year were most commonly represented (46%). Thirty-nine percent of cases had been exposed to horses with confirmed or suspected strangles (Streptococcus equi subsp equi infection) within the previous 8 weeks. Most frequent signs were unilateral or bilateral swelling of the throat region (65%), respiratory stertor/dyspnoea (35%), purulent nasal discharge (20%), inappetence and signs of depression (15%), and dysphagia (9%). All horses had a soft tissue density in the retropharyngeal region on radiographs. Rhinopharyngoscopy, ultrasonography, haematology as well as cytological and microbial analysis of material aspirated from the soft tissue swelling facilitated diagnosis in some horses. Fifteen horses (33%) were treated with procaine penicillin intramuscularly for 4 to 7 days followed by oral trimethoprim-sulphadimidine for 7 to 14 days. Non-steroidal anti-inflammatory drugs were administered to 6 horses. Four required tracheostomy for severe respiratory distress. The 15 horses treated medically responded to treatment and were discharged from hospital. Three horses (6%) with mild signs received no treatment and recovered uneventfully. Twenty-eight horses (61%) underwent general anaesthesia and surgical drainage of a RPLN abscess. Nineteen received procaine penicillin G for 4 to 7 days. Four of the nine horses that did not receive antibiotic treatment after surgery required further surgical drainage 10 days to 7 weeks after the initial surgery . Limited follow-up information was available for 37 horses. Thirty-two horses were considered to have made complete recovery, 3 horses had died through misadventure and 2 had been euthanased because of chronic ill-thrift .     

Ventral mandibulectomy for removal of oral tumours in the dog: Surgical technique and results in 19 cases

The purpose of this retrospective study is to describe in detail a novel ventral approach for mandibulectomy and the results in 19 dogs. The medical records of 19 dogs that received a partial or total unilateral mandibulectomy with the new ventral approach were reviewed. Information obtained included signalment, tumour type, extent of mandibulectomy, removal of regional lymph nodes, intrasurgical complications, immediate postoperative complications, histopathological diagnosis and study of margins. Intrasurgical complication occurred in one dog (haemorrhage) and required a blood transfusion. Postoperative morbidity was minor and included transient ventral cervical swelling and self‐limiting sublingual swelling (two dogs). All 19 animals were discharged between 24 and 48 hours of the procedure, and appetite was considered normal at discharge. Some perceived advantages of this procedure include easy identification of all the important anatomic structures in the area, including the inferior alveolar artery and temporo‐mandibular joint, and the fact that osteotomy of the zygomatic arch is not necessary (in case of caudal mandibulectomy). In addition, dissection of both mandibular and retropharyngeal lymph nodes is easily achieved by caudal extension of the same skin incision.     

Marsupialization and iodine sclerotherapy of a branchial cyst in a horse

A 6-month-old Morgan colt was evaluated because of a 10-cm right-sided retropharyngeal swelling. The swelling was soft and moveable on examination, and palpation did not elicit signs of pain. Radiography revealed a large space-occupying mass ventral to the second cervical vertebra; ultrasonography revealed an anechoic fluid-filled structure with a well-defined hyperechoic capsule. Fine-needle aspiration yielded a viscous amber fluid. Cytologic evaluation indicated that the fluid was an exudate; anaerobic and aerobic bacterial culture did not yield any growth. Histologic examination of a portion of the cyst capsule revealed a connective tissue wall lined by pseudostratified columnar to cuboidal epithelium, consistent with a branchial cyst. The cyst wall was marsupialized to the skin, and iodine sclerotherapy was performed twice daily for 14 days, at which time forceps were introduced into the cyst and the cyst lining was removed. The site was allowed to heal by second intention, but 10 days later, the swelling recurred. An incision was made over the previous marsupialization site, and residual remnants of the cauterized cyst lining were removed with a forceps. The foal did not have any other complications during the subsequent 2 years. Branchial arch cysts are uncommon embryonic anomalies of horses, mice, cats, dogs, and cattle. Results suggest that marsupialization and iodine sclerotherapy may be a viable alternative to surgical excision in horses with branchial cysts; however, the entire cyst lining must be removed at the completion of sclerotherapy to prevent recurrence and abscess formation.     

Radiographic and computed tomographic appearance of caseous lymphadenitis in a goat

A 2‐year‐old Boer doe was presented with respiratory distress and severe inspiratory dyspnea. Cervical and thoracic radiographs revealed a marked retropharyngeal soft tissue mass effect, several mineralized pharyngeal and retropharyngeal structures, and a pulmonary mass. Computed tomography (CT) revealed a severely enlarged right medial retropharyngeal lymph node, which caused laryngeal compression, leading to upper airway obstruction. Multiple cervical and thoracic lymph nodes, and the pulmonary mass had an irregular layered/laminated pattern of mineralization. Imaging findings were consistent with caseous lymphadenitis, and further confirmed with culture, necropsy, and histopathology. This is the first report of CT appearance of caseous lymphadenitis in a goat.     

Plexiform vascularisation of a retropharyngeal lymph node in a cat

Plexiform vascularisation of a retropharyngeal lymph node is described in an adult cat. The cat presented with a chronic history of inspiratory stridor and a slowly growing mass in the cranial cervical area. Clinical signs resolved after excision of the affected node. This appears to be the first clinical report of plexiform vascularisation of a retropharyngeal lymph node and its treatment in a cat.     

Branchial remnant cysts of mature and juvenile horses

This clinical report describes 8 cases of branchial remnant cysts (BRC) in the horse. The horses presented with bimodal age distribution, with 5 cases in mature horses (age 8–21 years) and 3 in foals (age 1, 6 and 10 months). Mature cases presented for dysphagia or intermittent oesophageal obstruction (2/5), and retropharyngeal swelling (3/5), whereas respiratory stridor and visible mass were presenting complaints in the foals. Presence of a right‐sided (5/8) or dorsally located (2/8) palpable retropharyngeal mass of 3–35 cm diameter was noted clinically; one left‐sided mass was identified as an incidental finding at necropsy. Ultrasonography typically revealed a thick‐walled cyst containing hypoechoic fluid with dependent hyperechoic masses consistent with blood clots. Radiographs and upper airway endoscopy were also consistent with a retropharyngeal mass. Fluid cytology revealed chronic haemorrhage in 6/8 cases, and squamous epithelial cells in one case. Histopathology in all cases demonstrated an epithelium‐lined cyst with no smooth muscle or thyroid tissue. Two cases was subjected to euthanasia; one due to concurrent laryngeal anomalies and one due to financial constraints. The remaining 5 cases were treated via surgical excision. Post operatively, right laryngeal hemiplegia was observed in 4/5 cases. All previous reports of BRC in the horse have described juvenile individuals. Brachial remnant cyst should be considered a differential diagnosis for mature horses with masses of the throatlatch area and can be definitively diagnosed by the presence of squamous epithelium in aspirated fluid or by histopathology of the excised mass. Right recurrent laryngeal nerve damage is a common complication of surgery.     

COMPUTED TOMOGRAPHIC FEATURES OF BASIHYOID ECTOPIC THYROID CARCINOMA IN DOGS

Eight dogs with a firm, nonpainful swelling in the ventral laryngeal region and with a final diagnosis of ectopic thyroid carcinoma were investigated by Computed Tomography (CT) at six different institutions. Computed Tomography findings were reviewed, focusing on lesion volume, shape, margins, relationship with surrounding structures and adjacent vessels, attenuation characteristics, and presence of metastases. Ectopic thyroid carcinomas were seen as oval‐to‐bilobed masses centered on the basihyoid bone with associated bone lysis, highly vascularized capsules with central poorly contrast enhancing areas. In all cases there was laryngeal wall infiltration, in two dogs invasion of the laryngeal lumen and in one case invasion of the ventral muscular and subcutaneous plane. Metastases were found in retropharyngeal lymph nodes (three cases) and in the lung (two cases). Ectopic thyroid carcinoma should be considered in the differential diagnosis when a mass in the basihyoid region is present. Described CT features may be typical for ectopic thyroid neoplasia and could be used to help decide the therapeutic plan.     

Corynebacterium equi in cattle and pigs

Summary The cervical lymph nodes of pigs, the retropharyngeal and submandibular lymph nodes of cattle and faecal samples from both animal species were examined for the presence of Corynebacterium equi. The organism was recovered from 19 (35 per cent) of 54 porcine cervical lymph nodes and from 0 of 54 bovine retropharyngeal and submandibular lymph nodes. Fifteen (50 per cent) of 30 bovine faecal and 11 (35 per cent) of 31 porcine faecal samples yielded C. equi.     

Immunohistochemical and histopathological studies of fixed rabies virus in goats

The purpose of this study was to systematically demonstrate and compare the pathological and immunohistochemical changes in goats which were infected by a fixed rabies virus that was used in vaccine production. In the histopathological examinations, varying degrees of inflammatory, degenerative and necrotic changes were detected in the central nervous system. In the preparations stained by the immunoperoxidase (IP) method, intra- and/or extracellular viral antigens were observed on the cerebellum, cornu ammonis, thalamus, pons, nucleus caudatus, spinal cord, medulla oblongata, Gasserian ganglion, eye and retropharyngeal lymph nodes. In the preparations stained by the immunofluorescence (IF) method, intra- and/or extracellular viral antigens were seen in the same locations with the exception of the retropharyngeal lymph nodes. It was also observed that the antigens were qualitatively and quantitatively well stained with both methods. However, the visibility of antigens in the retropharyngeal lymph nodes and eye, and the facilities of applying made the IP method much more advantageous than the IF method.     

山西黄土高原地区羊鼻蝇蛆病流行病学调查和病理学观察

通过对山西黄土高原区域羊鼻蝇蛆感染情况调查和病理学研究,以明确该地区羊鼻蝇蛆的感染率和该病的病理变化。春秋两个季节对羊鼻蝇蛆感染情况进行调查,对307例绵羊进行羊头剖检,检查羊鼻蝇蛆病的各龄幼虫感染情况,同时观察病理变化,并采取感染羊的鼻黏膜、咽后淋巴结、脑和肺组织进行病理组织学检查。春季检查157例,鼻蝇蛆感染患羊34例,感染率达22%;秋季检查150例,感染患羊70例,感染率达47%;春秋两季平均感染率为34%。病理变化主要表现为:鼻黏膜出现不同损伤和增生性炎,咽后淋巴结炎性细胞浸润,有的病例出现肺气肿,脑组织水肿。免疫组织化学染色结果表明,检出虫体的羊与未检出虫体羊比较,咽后淋巴结IgA分泌细胞和IgG分泌细胞呈增高趋势,尤其是淋巴结髓质中IgA分泌细胞和IgG分泌细胞明显增多。     

Percutaneous puncture technique for treating persistent retropharyngeal lymph node infections in seven horses

Between 1999 and 2001, seven horses with fever, dysphagia and a history of chronic upper respiratory tract infection lasting between three weeks and three months were examined. They had been treated unsuccessfully with a variety of antibiotics for three to four weeks. A deep abscess in a retropharyngeal lymph node was diagnosed in each case by clinical examination, endoscopy and echographic examination of the retropharyngeal region. The infected retropharyngeal lymph node of each horse was punctured with a spinal needle under ultrasound guidance. Pus was aspirated from four of the horses, and their abscesses were then rinsed with 0.9 per cent saline solution, and antibiotics (sodium ceftiofur or penicillin) were injected. In the other three horses the pus was too viscous to be aspirated, and the enlarged lymph node was opened along the tract of the needle and rinsed with chlorhexidine. All the horses were treated with penicillin for two weeks and in six of them the clinical signs gradually disappeared. The other horse continued to show fever and the penicillin treatment was continued for another 10 days, after which the signs gradually disappeared over a period of two months.     

Corynebacterium equi in cattle and pigs

Summary

The cervical lymph nodes of pigs, the retropharyngeal and submandibular lymph nodes of cattle and faecal samples from both animal species were examined for the presence of Corynebacterium equi. The organism was recovered from 19 (35 per cent) of 54 porcine cervical lymph nodes and from 0 of 54 bovine retropharyngeal and submandibular lymph nodes. Fifteen (50 per cent) of 30 bovine faecal and 11 (35 per cent) of 31 porcine faecal samples yielded C. equi.     

IMAGING FINDINGS IN A COW WITH A RETROPHARYNGEALLY DISPLACED MAGNET

This report describes the ultrasonographic and radiographic findings and the treatment of a Swiss Brown cow with a retropharyngeal abscess caused by improper administration of a magnet.     

Bilateral removal of the mandibular and medial retropharyngeal lymph nodes through a single ventral midline incision for staging of head and neck cancers in dogs: a description of surgical technique

Currently, there is no standard protocol for removal of regional lymph nodes for the staging of head and neck cancers in dogs. Palpation and fine needle aspiration of mandibular lymph nodes are most commonly performed for staging of head and neck cancers. Although cytology is commonly performed for staging of head and neck, cancers histopathology is required for definitive lymph node staging. When regional lymph node biopsy is performed, mandibular lymph nodes are most commonly sampled due to their accessibility. The medial retropharyngeal lymph nodes may be the most relevant draining lymph node of the head and neck, but they are not routinely sampled due to their anatomic location medial to the salivary glands. The technique described here will allow for a standardized surgical approach for the efficient removal of both mandibular and medial retropharyngeal lymph nodes for staging of head and neck tumours via a single ventral midline approach.     

Metastasizing oral squamous cell carcinoma in an aged pig

A 10-year-old, female, pot-bellied pig (Sus scrofa) experienced a 3-month history of reduced appetite, dysphagia, and weight loss. Clinical examination revealed a mass in the left part of the oral cavity extending from the hard to the soft palate. At necropsy, a firm, white, poorly demarcated ulcerated mass at the left hard and soft palate with metastases to the left retropharyngeal lymph node and the lung was observed. Additional findings included a uterine adenocarcinoma, a hepatocellular adenoma, and nodular hyperplasias in spleen and adrenal glands. Histologically, the poorly demarcated, infiltrative growing oral mass consisted of islands, cords, and single epithelial cells with moderate squamous differentiation. Cells were strongly positive for cytokeratin by immunohistochemistry. Similar cells were found in the left retropharyngeal lymph node and the lung. The present findings represent the first report of a metastasizing oral squamous cell carcinoma in a pig.     

Quantitation and localization of immunoglobulin E containing cells in bovine lymphoid tissues

Although recent studies have begun to describe and quantify IgE responses in bovine serum and secretions, little is known about the distribution and quantity of IgE containing cells in cattle. In the present study, cells with cytoplasmic IgE were quantitated in bovine lymphoid tissues, using immunoperoxidase staining and evaluation by an image analysing computer (Quantimet). Frozen sections from retropharyngeal, bronchial and mesenteric lymph nodes, tonsil and spleen were stained from 11 calves, some of which had been exposed to antigen by aerosol or injection. Although individual variability was considerable, bronchial and mesenteric lymph nodes generally contained the greatest percentage of IgE containing cells, while retropharyngeal lymph node, tonsil, and spleen had less. Parenteral immunization with ovalbumin appeared to increase the splenic percentage, while aerosol exposure to ovalbumin was associated with a greater percentage of IgE containing cells in bronchial lymph nodes. Comparison of the present results with those reported for other species shows some similar trends in IgE localization.