Identification of an ectopic periorbital lymph node in two horses

Background: To describe the clinical presentation and treatment of an ectopic periorbital lymph node in two young horses. Case Description: Two warm-blood horses were presented at the equine clinic of the University of Liège with a periorbital non-painful mass. Differential diagnosis included neoplasm (lymphoma), (sterile) abscess, cyst, ectopic lacrimal gland tissue, hematoma, adipose tissue, or ectopic lymphoid tissue. Information collected included physical and ophthalmic examination findings, results of the ocular and periocular ultrasound, surgical procedure, histopathology, and follow-up. Masses of 2 × 2 cm and 3 × 2 cm subcutaneous, ovoid, smooth, and firm mass were observed in the zygomatic region of the head. On ultrasound, the mass appeared as a hypoechoic subcutaneous structure. Cytology showed a mixed lymphocytic cell population. No abnormal mitotic activity was observed. Histopathology revealed a chronic markedly reactive lymph node. Conclusion: To the authors’ knowledge, this is the first description of periorbital ectopic lymph nodes in veterinary medicine. Ectopic lymph nodes should therefore be included in the differential diagnosis of periocular masses in animals. Surgery was easily performed and was curative

Nasopharyngeal stenosis in 3 dogs: preliminary report

peer reviewe

Duration of corneal anaesthesia following multiple doses and two concentrations of tetracaine hydrochloride eyedrops on the normal equine cornea

REASONS FOR PERFORMING STUDY: There is a clinical impression that tetracaine hydrochloride (THCl) eyedrops is a suitable topical anaesthetic in horses. OBJECTIVE: To determine the duration of corneal anaesthesia following instillation of multiple doses and 2 concentrations of THCl in 10 healthy horses. METHODS: The corneal touch threshold (CTT) was determined, in both eyes, before (basal CTT) and after application of one drop of 0.5% THCl, 2 drops at a 1 min interval of 0.5% THCl or one drop of 1% THCl. CTT was measured in mm every 5 min until complete recovery of the basal CTT. Treatments were separated by an interval of at least one week. RESULTS: Corneal sensitivity was significantly reduced from baseline values for 30, 60 and 50 min after application of one drop of 0.5% THCl, 2 drops of 0.5% THCl and one drop of 1% THCl, respectively. Mean maximal anaesthetic effects, corresponding to a CTT of 0 mm, lasted 5.5, 16 and 15.25 min and maximal anaesthetic effect was present in 55, 90 and 80% of eyes, 5 min after application of one drop of 0.5% THCl, 2 drops of 0.5% THCl and one drop of 1% THCl, respectively. CONCLUSIONS: The application of a second drop or the use of more concentrated eyedrops significantly increases duration of both anaesthesia and maximal anaesthetic effect. POTENTIAL RELEVANCE: Duration of corneal anaesthesia following tetracaine instillation was established enabling a better use when performing diagnostic and therapeutic procedures. Comparison of tetracaine with other ocular anaesthetics needs to be published in the future

Tolerance of different concentrations of tetracaine hydrochloride eyedrops and its effect on the tear break up time in healthy horses (abstract)

peer reviewe

Study of Spinal Cord Evoked Injury Potential by Use of Computer Modeling and in Dogs with Naturally Acquired Thoracolumbar Spinal Cord Compression

peer reviewedOBJECTIVE: To add objective measurements of the characteristics of evoked injury potentials (EIP) and their relations to clinical severity in dogs with thoracolumbar spinal cord damage. ANIMALS: 25 dogs with naturally acquired spinal cord compression attributable to disk extrusion or vertebral fracture at the level of the thoracolumbar junction and with various degrees of paresis/paralysis. PROCEDURE: Spinal cord potentials evoked by tibial nerve stimulation were recorded every 5 to 10 mm at the lamina level in the vicinity of the cord compression. This allowed an EIP to be recorded even in the least handicapped dogs. A computer model yielded information about the waveform changes of the EIP in the vicinity of conduction blocks. RESULTS: The EIP waveform changed from biphasic to monophasic a short distance caudad to the location of spinal cord compression. Location of a maximal conduction block was measured in relation to position of the electrodes recording this waveform change. The distance between the assumed conduction block and the actual spinal cord compression was larger in the most affected dogs. The amplitude of the EIP was not related to severity of the clinical picture; however, the proximity of the recording electrode to the spine influenced the amplitude and the waveform of the EIP. CONCLUSION AND CLINICAL RELEVANCE: Change in the EIP waveform from biphasic to monophasic makes it possible to estimate the conduction block location along the spinal cord. A large distance between the assumed conduction block and site of actual cord compression could be an objective argument to confirm severity of a lesion

CT FEATURES OF A LACRIMAL GLAND TUMOR IN A DOG

Background: In the dog, neoplasms of the lacrimal gland are rare. Lacrimal cysts were also reported. Computed tomography (CT) scan findings of these lacrimal gland abnormalities have not been described in dogs. Purpose: The present report describes clinical and CT features of a lacrimal gland tumor in a dog. Methods: A 3,5 year old female intact Leonberger with a good general health status was presented with a progressive swelling at the level of the supero-temporal area of the left upper eyelid and of the bulbar conjunctiva since 3 weeks. Ocular examination revealed a slight enophthalmia and a ventronasal strabismus, the presence of a firm mass in the upper eyelid which was anteriorly well circumscribed and extending posteriorly between the globe and the orbital ligament. Findings: A CT scan pre- and post- contrast studies of the head were performed. A 3 cm hypoattenuating (+/- 10 HU) ovoid mass was observed dorsolateral to the indented left globe. This mass was well circumscribed by an unevenly thick irregular soft tissue- attenuating wall (50HU), which was strongly contrast-enhanced (150HU) and measured about 2 to 10mm in thickness. The left globe was displaced caudoventromedially. No adjacent bone lesion, or foreign body was observed. No normal left lacrimal gland was observed. These findings were suggestive of an abscess or an orbital tumor with a necrotic/cystic center; a lacrimal cyst was considered less likely because of the unevenness and the thickness of the wall. Complete surgical ablation was done by a modified lateral orbitotomy. Histopathology revealed a mixed benign tumor of the lacrimal gland and a lymphocytic necrotic adenitis. Six months postoperatively no recurrence is noted and the tear production is 15mm/min. Conclusion: The lacrimal gland is located dorsolateral to the globe and produces tears. In human medicine, a wide range of lacrimal gland pathologies were described and assessed by computed imaging techniques. Pleomorphic adenomas (mixed benign tumor) could reveal irregular bone erosion and could undergo malignant transformation. In dogs, lacrimal cysts were described as thin walled structures.4 Only few articles reported lacrimal gland tumor. To the authors knowledge, CT findings of a lacrimal gland tumor have not been described previously. In conclusion, lacrimal gland tumor should be included in the differential diagnosis of a firm ovoid cystic/necrotic mass dorsolateral to the orbit