Abstract

Megaesophagus is a frequently reported motility disorder affecting the canine esophagus, characterized by ineffective esophageal peristalsis, dilation, and regurgitation.^1,2,6 Megaesophagus has been reported in phocids in rehabilitation and managed care facilities but information on prevalence, predisposing factors, and clinical presentation is lacking.^3,4,5 The objectives of this study were to determine prevalence of megaesophagus in rehabilitating phocids and characterize predisposing factors, clinical signs, diagnostic and management options. A retrospective review of records from phocids admitted to three rehabilitation facilities spanning a 15-year period was conducted. Thirteen cases of megaesophagus were identified with an overall prevalence of 0.2%. Prevalence was 3% in Atlantic harbor seals (Phoca vitulina concolor), 0.17% in Pacific harbor seals (Phoca vitulina richardii), and 0.04% in Northern elephant seals (Mirounga angustirostris) (NES) with a significantly higher prevalence in harbor seals when compared to NES (p<0.001). The single case of megaesophagus identified in a NES was secondary to persistent right aortic arch. Overall mortality was 92% (58% of seals found dead; 42% euthanized; 8% survived to release). Pups represented 92% of cases and 83% were diagnosed within 10 days of weaning. Clinical signs included lethargy (100%), regurgitation (76%), and dyspnea (62%). Medical management included gastroprotectants, prokinetics, corticosteroids, and fluid therapy. One animal survived to release after manual removal of impacted esophageal material and tube feedings administered in an elevated position. The results of this study can assist clinicians in the early detection of megaesophagus and aid in intervention techniques that may reduce patient mortality.

Acknowledgements

The authors thank the staff and volunteers at the Mystic Aquarium Animal Rescue Program, The Marine Mammal Center, Vancouver Aquarium, and Alaska SeaLife Center for their invaluable contributions to this project and their efforts in pinniped rehabilitation and conservation. In addition, the authors thank Laura Thompson for her assistance with statistics and Tenaya Norris for her assistance with case identification.

*Presenting author
⁺Student presenter

Literature Cited

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