In the eye of the beholder: suspected oculomotor nerve damage in a 10 yr old Alpaca

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The objective of this presentation is to present a case that is simple but not straightforward, and to emphasize the value of a thorough workup and physical exam in establishing a diagnosis and treatment plan.

A 10-year-old male intact alpaca presented to the Cornell University Ophthalmology service on December 3rd, 2013. The alpaca had a two-day history of blepharospasm and epiphora in the right eye, following being moved to a new pasture. He was treated by the referring veterinarian with triple antibiotic ointment and Flunixin meglumine to no avail. On presentation, the right eye was severely mydriatic with marked epiphora and ptosis as well as absent PLR. Ophthalmic exam also revealed decreased medial motion of the globe. On general physical exam, there was decreased airflow from the right nostril and decreased sensation in the right nostril and nasal septum. The remainder of his physical exam was unremarkable. Neurolocalization of the clinical signs including mydriasis, ptosis, decreased medial motion of the globe and decreased sensation and airflow from the right nostril pointed to a lesion in the middle cranial fossa primarily affecting cranial nerve III. A CBC and chemistry panel did not reveal any significant abnormalities, and a radiograph of his skull did not show any evidence of obstruction in the nasal passages or other abnormalities.

The following day, airflow had improved from the right nostril and the right pupil had constricted slightly. A unilateral ophthalmologic exam was performed under sedation and an Arctium sp. (burdock) pappus bristle was discovered on the bulbar surface of the nictitans. The nictitans was everted using hemostats and a 7 x 8 mm piece of conjunctival tissue was excised using iris scissors. The alpaca was discharged the following day with triple antibiotic ointment. At the time of discharge, the right pupil was still mydriatic and so the etiology remains open for cause. Possible causes discussed include exposure to certain plant compounds, administration of a pharmacologic agent such as atropine, or the presence of a mass in the middle cranial fossa causing oculomotor nerve damage.

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alpaca; nerve damage; case studies; Oculomotor nerve damage


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