A Comparative Assessment of the Diagnosis of Swallowing Impairment and Gastroesophageal Reflux in Canines and Humans

Abstract

Swallowing impairment is a highly prevalent and clinically significant problem affecting people and dogs. There are myriad causes of swallowing impairment of which gastroesophageal reflux is the most common in both species. Similarities in anatomy and physiology between humans and canines results in analogous swallowing disorders including cricopharyngeus muscle achalasia, esophageal achalasia, hiatal herniation, and gastroesophageal reflux with secondary esophagitis and esophageal dysmotility. Accordingly, the diagnostic approach to human and canine patients with swallowing impairment is similar. Diagnostic procedures such as swallowing fluoroscopy, high-resolution manometry, pH/impedance monitoring, and endolumenal functional luminal imaging probe can be performed in both species; however, nasofacial conformation, increased esophageal length, and the difficulty of completing several of these procedures in awake dogs are inherent challenges that need to be considered. Human patients can convey their symptoms and respond to verbal cues, whereas veterinarians must rely on clinical histories narrated by pet owners followed by comprehensive physical examination and observation of the animal eating different food consistencies and drinking water. Dogs may also be unwilling to drink or eat in the hospital setting and may be resistant to physical restraint during diagnostic procedures. Despite the species differences and diagnostic challenges, dogs are a natural animal model for many oropharyngeal and esophageal disorders affecting people, which presents a tremendous opportunity for shared learnings. This manuscript reviews the comparative aspects of esophageal anatomy and physiology between humans and canines, summarizes the diagnostic assessment of swallowing impairment in both species, and discusses future considerations for collaborative medicine and translational research.

A One Health review of aerodigestive disease in dogs

“…137 Similar studies discriminating between nonacidic and acidic reflux and erosive and nonerosive esophagitis are lacking in dogs. 131 However, a study evaluating administration of esomeprazole with or without cisapride on reflux events in anesthetized dogs, found no change in the number of reflux events compared to placebo when esomeprazole was given as a sole agent despite significant increases in pH. 138 This study and others demonstrate active reflux in dogs despite treatment with PPIs.…”

“…Adjunctive diagnostic and monitoring strategies for GERD and EERD in veterinary medicine incorporate client surveys, treatment trials with proton pump inhibitors (PPIs), esophagoscopy, and rarely esophageal manometry and ambulatory pH probes 128‐131 . However, these have important limitations.…”

“…People with GERD and symptoms of heartburn have a prevalence of nonacidic reflux of 37.4% and 44.3% in patients with erosive esophagitis and nonerosive esophagitis, respectively 137 . Similar studies discriminating between nonacidic and acidic reflux and erosive and nonerosive esophagitis are lacking in dogs 131 . However, a study evaluating administration of esomeprazole with or without cisapride on reflux events in anesthetized dogs, found no change in the number of reflux events compared to placebo when esomeprazole was given as a sole agent despite significant increases in pH 138 .…”

“…A VFSS is considered the diagnosis of choice in dogs to detect subtle and segmental abnormalities in esophageal motility 216 . Detailed information on esophageal motility might also be achieved by HRM; however, this is not routinely available in clinical practice 131 …”

“…Adjunctive diagnostic and monitoring strategies for GERD and EERD in veterinary medicine incorporate client surveys, treatment trials with proton pump inhibitors (PPIs), esophagoscopy, and rarely esophageal manometry and ambulatory pH probes. 128 , 129 , 130 , 131 However, these have important limitations. Though a mainstay in clinical practice, treatment trials with client reporting are inherently prone to bias because of variable client vigilance, and a failure to recognize episodic or subtle clinical signs.…”