CASE REPORT: Paradoxical vestibular syndrome in a guinea pig

16 December 2019 – News

In exotic small mammals, vestibular syndrome is generally linked to chronic cases of otitis interna but this case report is possibly the first describing a sequela with subsequent paradoxical signs.

The report describes the case of a three-year-old female guinea pig, whose first physical examination revealed uveitis of the right eye, corneal ulceration, facial paresis and proprioceptive deficits in both right limbs.  The patient also showed left head tilt and ataxia, falling to the left side. These signals were suggestive of paradoxical vestibular syndrome but, as further examinations were declined, diclofenac (collyrium) for 7 days and enrofloxacin (oral) were prescribed for two weeks.

After seven months, the guinea pig was found to have deteriorated and a CT was scheduled.  Images revealed lysis of the occipital bone and that the right semi-circular canals had apparently been destroyed. A bacterial abscess or fungal granuloma were believed to be the most likely causes but neoplasia could not be ruled out. Differentiating between infectious and neoplastic required sampling and there were too many risks linked to a bone biopsy. Surgery was also not an option as the lesion was extensive.  In view of these factors, the authors suggested the administration of enrofloxacin, both oral and topically (right ear), and some supplementation in the feeding.

Forty days later, the animal showed severe lethargy and inappetence, having lost almost 30% of its body weight. Euthanasia was performed and a post mortem examination conducted.

The necropsy confirmed the existence of a hard mass that was compressing some cerebral lobes and the rostral cerebellum. Histopathology identified a suppurative osteomyelitis.

Ratliff et al. Paradoxical Vestibular Syndrome secondary to temporal bone osteomyelitis and chronic otitis interna in a guinea pig (Cavia porcellus). Journal of Exotic Pet Medicine 28 (2019), pp 3034