Disorders of gastrointestinal motility

Disorders of gastrointestinal motility represent a diagnostic and therapeutic challenge. Gastrointestinal motility disorders may result in delayed transit, accelerated transit, impaired re­laxation, or inappropriate relaxation.¹ The delayed transit dis­orders are the most important motility disorders of companion animals and may involve the esophagus (e.

Idiopathic megaesophagus. Idiopathic megaesophagus is the most common cause of regurgitation in the dog. The dis­order is characterized by esophageal hypomotility and dila­tion, progressive regurgitation, and loss of body condition. Several forms of the syndrome have been characterized, in­cluding congenital, acquired secondary, and acquired idio­pathic megaesophagus.^1,2

Gastric emptying disorders. Gastric emptying disorders are fairly common in dogs and cats, and are an important cause of nausea and vomiting. Primary conditions that have been associated with delayed gastric emptying include infectious and inflammatory diseases (e.g., IBD), gastric ulceration, and post-surgical gastroparesis, while secondary causes include electrolyte disturbances, metabolic disorders, concurrent drug usage (e.g., cholinergic antagonists, adrenergic agonists, or opioid agonists), acute stress, and acute abdominal inflam- mation.² Recovery from gastric dilation/volvulus (GDV) is almost always associated with significant myoelectrical and motor abnormalities in the dog.²

Small intestinal transit disorders. Several small intestinal disorders that are associated with altered transit have been described in the dog and cat, including IBD, post-surgical pseudo-obstruction, nematode infection, intestinal sclerosis, and radiation enteritis.² Vomiting and diarrhea are the most important clinical signs associated with these disorders.

Colonic motility disorders. Constipation, obstipation, and megacolon are primarily disorders of the domestic cat.^2,3 An extensive list of differential diagnoses (e.g., neuromuscular, mechanical, inflammatory, metabolic, endocrine, pharmacolo­gic, environmental, and behavioral causes) have been proposed, but most (>96%) cases are accounted for by idiopathic mega­colon (62%), pelvic canal stenosis (23%), nerve injury (6%), or Manx sacral spinal cord deformity (5%).^1,3

Dysautonomia. Dysautonomia is a generalized autonomic neuropathy that was originally reported in cats in Great Bri­tain, which has now also been documented in dogs and cats throughout Western Europe and the United States. The clini­cal signs reflect a generalized autonomic dysfunction, leading to megaesophagus and esophageal hypomotility, gastric dila­tion and delayed gastric emptying, ileus and intestinal pseudo­obstruction, and megacolon and obstipation.

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