Diagnosis and management of nasopharyngeal stenosis in four guinea pigs (Cavia porcellus)

Respiratory disease is common in guinea pigs (Cavia porcellus). As obligate nasal breathers, disease of the upper airway can result in significant dyspnea. Nasopharyngeal stenosis is defined as a luminal narrowing of the nasopharynx, which extends from the choana to the caudal margin of the soft palate. This condition can be acquired or congenital and has been diagnosed in other species. However, nasopharyngeal stenosis has not been previously described in guinea pigs. Four guinea pigs were presented with chronic, recurrent upper respiratory signs including stertor, oculonasal discharge, tachypnea, and dyspnea. All four animals had signs suggestive of upper respiratory tract disease on examination. Nasopharyngeal stenosis was identified at the rostral aspect of the nasopharynx at the level of the choana via computed tomography (CT) in all cases. Otitis media was also present in three of the four cases. Antibiotic therapy was instituted for all animals. Two of the four guinea pigs were treated with prednisolone and two were treated with meloxicam to control associated inflammation. One animal died 2 months after diagnosis due to complications from severe otitis media. One individual was euthanized due to progressive disease after a year and a half of treatment. One guinea pig was lost to follow up after 6 months. The remaining guinea pig was alive at the time this case series was written (11 months after initial diagnosis) but continues to have signs of upper airway disease. Nasopharyngeal stenosis is an important differential diagnosis for persistent upper respiratory signs in guinea pigs. CT was diagnostic in all cases, identifying nasopharyngeal stenosis at the level of the choana, and allowed identification of comorbidities (otitis media and rhinitis). Medical management resulted in survival times from 2 months to a year and a half following diagnosis. Further investigation into minimally invasive interventions such as balloon dilation and stent placement are warranted for future cases.