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Esophageal Motility Disorders

Background

The esophagus functions solely to deliver food from the mouth to the stomach where the process of digestion can begin. Efficient transport by the esophagus requires a coordinated, sequential motility pattern that propels food from above and clears acid and bile reflux from below. Disruption of this highly integrated muscular motion limits delivery of food and fluid, as well as causes a bothersome sense of dysphagia and chest pain. Disorders of esophageal motility are referred to as primary or secondary esophageal motility disorders and categorized according to their abnormal manometric patterns. See the images below.

The typical picture of achalasia. Note the "bird-b

The typical picture of achalasia. Note the “bird-beak” appearance of the lower esophageal sphincter (LES), with a dilated, barium-filled esophagus proximal to it. Image courtesy of Andrew Taylor, MD, Professor, Abdominal Imaging, Department of Radiology, University of Wisconsin Medical School, Madison.

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The response to amyl nitrate (a smooth muscle rela

The response to amyl nitrate (a smooth muscle relaxant), with partial relaxation of the lower esophageal sphincter (LES), allows some barium to pass through it into the stomach. Image courtesy of Andrew Taylor, MD, Professor, Abdominal Imaging, Department of Radiology, University of Wisconsin Medical School, Madison.

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Esophagram of a 65-year-old man with rapid-onset d

Esophagram of a 65-year-old man with rapid-onset dysphagia over 1 year. Although esophagram shows a typical picture of achalasia, this patient had adenocarcinoma of the gastroesophageal junction. This is an example of pseudoachalasia, which reinforces the absolute need for esophagogastroduodenoscopy (EGD) in patients with radiologic diagnosis of achalasia. Image courtesy of Andrew Taylor, MD, Professor, Abdominal Imaging, Department of Radiology, University of Wisconsin Medical School, Madison.

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An esophagram demonstrating the corkscrew esophagu

An esophagram demonstrating the corkscrew esophagus picture observed in a patient with manometry confirmed findings of diffuse esophageal spasm (DES). Image courtesy of Andrew Taylor, MD, Professor, Abdominal Imaging, Department of Radiology, University of Wisconsin Medical School, Madison.

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Response to amyl nitrate, with disappearance of th

Response to amyl nitrate, with disappearance of the spasm on esophagram. Image courtesy of Andrew Taylor, MD, Professor, Abdominal Imaging, Department of Radiology, University of Wisconsin Medical School, Madison.

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Anatomy

The tubular esophagus is a muscular organ, approximately 25 cm in length, and has specialized sphincters at proximal and distal ends. The upper esophageal sphincter (UES) is comprised of several striated muscles, creating a tonically closed valve and preventing air from entering into the gastrointestinal tract. The lower esophageal sphincter (LES) is composed entirely of smooth muscle and maintains a steady baseline tone to prevent gastric reflux into the esophagus.

The body of the esophagus is similarly composed of 2 muscle types. The proximal esophagus is predominantly striated muscle, while the distal esophagus and the remainder of the GI tract contain smooth muscle. The mid esophagus contains a graded transition of striated and smooth muscle types. The muscle is oriented in 2 perpendicular opposing layers: an inner circular layer and an outer longitudinal layer, known collectively as the muscularis propria. The longitudinal muscle is responsible for shortening the esophagus, while the circular muscle forms lumen-occluding ring contractions.

Esophageal peristalsis

The coordination of these simultaneously contracting muscle layers produces the motility pattern known as peristalsis. Peristalsis is a sequential, coordinated contraction wave that travels the entire length of the esophagus, propelling intraluminal contents distally to the stomach. The LES relaxes during swallows and stays opened until the peristaltic wave travels through the LES, then contracts and redevelops resting basal tone. Low peristaltic amplitudes normally occur at the transition zone between the striated and smooth muscle portions; however, the peristalsis is uninterrupted.

Primary peristalsis is the peristaltic wave triggered by the swallowing center. The peristaltic contraction wave travels at a speed of 2 cm/s and correlates with manometry-recorded contractions. The relationship of contraction and food bolus is more complex because of intrabolus pressures from above (contraction from above) and the resistance from below (outflow resistance).

The secondary peristaltic wave is induced by esophageal distension from the retained bolus, refluxed material, or swallowed air. The primary role is to clear the esophagus of retained food or any gastroesophageal refluxate.

Tertiary contractions are simultaneous, isolated, dysfunctional contractions. These contractions are nonperistaltic, have no known physiologic role, and are observed with increased frequency in elderly people. Radiographic description of this phenomenon has been called presbyesophagus.

Esophageal motility disorders

Esophageal motility disorders are not uncommon in gastroenterology. The spectrum of these disorders ranges from the well-defined primary esophageal motility disorders (PEMDs) to very nonspecific disorders that may play a more indirect role in reflux disease and otherwise be asymptomatic. Esophageal motility disorders may occur as manifestations of systemic diseases, referred to as secondary motility disorders.

Esophageal motility disorders are less common than mechanical and inflammatory diseases affecting the esophagus, such as reflux esophagitis, peptic strictures, and mucosal rings. The clinical presentation of a motility disorder is varied, but, classically, dysphagia and chest pain are reported. In 80% of patients, the cause of a patient’s dysphagia can be suggested from the history, including dysmotility of the esophagus. Before entertaining a diagnosis of a motility disorder, first and foremost, the physician must evaluate for a mechanical obstructing lesion.

Esophageal motility disorders discussed in this article include the following:

Achalasia

Spastic esophageal motility disorders, including diffuse esophageal spasm (DES), nutcracker esophagus, and hypertensive LES

Nonspecific esophageal motility disorder (inefficient esophageal motility disorder)

Secondary esophageal motility disorders related to scleroderma, diabetes mellitus, alcohol consumption, psychiatric disorders, and presbyesophagus

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