Rudolph's Pediatrics, 22nd Ed.

CHAPTER 393. Disorders of Esophageal Motility

Neelesh A. Tipnis

Esophageal motility disorders are classified as primary when they are one of a small number of isolated disorders of motility or as secondary when associated with known disease processes (Table 393-1). A basic understanding of normal esophageal motility allows appreciation of the diagnostic criteria for various motility disorders.

The esophagus is a dynamic muscular conduit connecting the oropharynx to the stomach. Two sphincters, the upper esophageal sphincter (UES) and lower esophageal sphincter (LES), divide the esophagus from the oropharynx and stomach respectively. The esophagus is composed of striated muscle in the upper third and smooth muscle in the lower two thirds.

Coordination of the muscles of the pharynx, UES, esophagus, and LES are required for propulsion of food and liquid bolus to the stomach. Swallowing induces relaxation and opening of the UES to allow transfer of food and liquid bolus from the pharynx into the upper esophagus. This is followed by a vagally mediated sequential contraction of the muscles in the esophageal body—termed primary peristalsis. Similar to the UES, the LES relaxes with initiation of the swallow to allow the bolus to enter the stomach. Distension of the esophageal body wall stimulates secondary peristalsis, which is identical to primary peristalsis except that there is no swallow, pharyngeal contraction, or UES relaxation/contraction.

Table 393-1. Esophageal Motility Disorders

Primary

Achalasia

Diffuse esophageal spasm

High-amplitude esophageal contractions (HAEC) or nutcracker esophagus

Nonspecific esophageal motility disorder

Secondary

Scleroderma

CREST syndrome*

Polymyositis

Dermatomyositis

Mixed connective tissue disease (with Raynaud phenomenon)

Muscular dystrophy

Diabetic neuropathy

Chronic intestinal pseudoobstruction

Esophageal atresia

* CREST, calcinosis, Raynaud phenomenon, esophageal dysmotility, sclerodactyly, and telangiectasia.

Relaxation of the LES that is not associated with swallowing is termed transient lower esophageal sphincter relaxation (TLESR). TLESRs are an important protective mechanism, allowing belching or burping. However, TLESRs are also the main mechanism for gastroesophageal reflux in infants, children, and adults.1,2

FIGURE 393-1. Manometric findings in esophageal motility disorders. The tracings depict muscle contraction forces beginning in the pharynx and moving caudally through the upper esophageal sphincter (UES), esophageal body, and lower esophageal sphincter (LES). In healthy individuals, the UES and LES appear as zones of high pressure. With a swallow (indicated by pharyngeal contractions), pressure in both sphincters falls, and a contraction wave that starts in the pharynx progresses down the esophagus. In achalasia, the LES pressure is increased (hypertensive) and fails to relax with swallows; all esophageal contractions occur simultaneously (aperistaltic). The amplitude of the esophageal contractions is typically reduced (hypotensive). In diffuse esophageal spasm, 30% to 80% of esophageal contractions are aperistaltic, the duration of the contractions are prolonged (20 seconds or greater), and the amplitude of the contractions may be increased, normal, or decreased. In nutcracker esophagus, the esophageal contractions are peristaltic but of large amplitude, typically greater than 180 mm Hg. In secondary motility disorders such as gastroesophageal reflux disease or scleroderma, the esophageal contractions and LES pressures are reduced. Additional findings in secondary motility disorders are prolonged esophageal contractions, aperistaltic contractions, and multiple peaked contractions. (Modified from Wiener CM: Harrison’s Principles of Internal Medicine, 16th edition. New York, McGraw-Hill, 2005.)

PRIMARY ESOPHAGEAL MOTILITY DISORDERS

Primary esophageal motility disorders are uncommon in otherwise healthy children. Dysphagia, chest pain, or recurrent foreign-body obstruction are the usual modes of presentation, although failed esophageal peristalsis can result in spilling of residual food into the airway with symptoms of recurrent aspiration pneumonia. Diagnosis is often suspected following an esophagram, which is a dynamic study that shows the absence of an anatomic obstruction and may show abnormal peristalsis. Esophageal manometry is required for a specific and conclusive diagnosis (Fig. 393-1).

ACHALASIA

Achalasia is a motor disorder of the esophagus with characteristic radiographic features on barium swallow (a dilated esophagus with air fluid levels and a stereotypical “birds-beak” appearance at the gastroesophageal junction) (eFig. 393.1 ) and manometric findings as shown in Figure 393-1. The pathophysiology of achalasia is not certain, but it seems likely that in many cases it is due to an autoimmune-mediated process resulting in a loss of inhibitory relaxation of the LES. Congenital or syndromatic cases likely have a separate etiology with specific genetic abnormalities being identified in some associated syndromes (see below). Presenting symptoms include dysphagia, regurgitation, recurrent pneumonia, weight loss, and chest pain. The pathophysiology of achalasia is not certain, but it seems likely that in many cases it is due to an autoimmune-mediated process resulting in a loss of inhibitory relaxation of the LES. Congenital or syndromatic cases likely have a separate etiology with specific genetic abnormalities being identified in some associated syndromes (see below). The overall incidence of achalasia is 0.4 to 0.6 per 100,000, with only about 5% of cases occurring in children and the average age of diagnosis being about 9 years old. Achalasia occurs in association with other disorders and syndromes, as listed in Table 393-2. Chagas disease can be indistinguishable from achalasia and should be considered in patients who have traveled to endemic areas, including the southern United States and Latin America.

Surgical treatment with a Heller myotomy (usually with an antireflux procedure) is becoming the treatment of choice for achalasia.8 Pneumatic balloon dilation of the LES9 or injection of the LES with botulinum toxin10 provides transient relief, but the requirement for repeated treatment makes these therapies less attractive for treatment of childhood achalasia. Following treatment for achalasia, some degree of dysphagia for solids often persists because of persistent aperistalsis of the esophagus. This requires that patients chew food well and often need liquid chasers to clear the esophagus. There is also a long-term risk of esophagitis, Barrett esophagus, and esophageal adenocarcinoma requiring consistent, long-term follow-up through adulthood.

Table 393-2. Disorders and Syndromes Associated with Achalasia

Deafness, vitiligo, short stature, and muscle weakness

Allgrove syndrome or triple-A syndrome (achalasia, alacrima, and adrenocorticotropin insensitivity)

Down syndrome

Alport syndrome

Familial achalasia

Familial visceral neuropathy

Familial dysautonomia

Sjogren syndrome

Autoimmune polyendocrinopathy syndrome

Multiple endocrine neoplasia type 2B

Addison disease/adrenoleukodystrophy

Chagas disease trypanosomiasis

Leiomyoma or other tumors of the stomach may masquerade as achalasia

OTHER PRIMARY ESOPHAGEAL MOTILITY DISORDERS

Diffuse esophageal spasm (prolonged simultaneous contractions of the esophagus) and high-amplitude esophageal contractions (> 180 mm Hg, also called nutcracker esophagus) are rarely described in children. Treatment with anticholinergics, nitroglycerin, long-acting nitrates, nifedipine and botulinum toxin injection, and surgery all have inconsistent reported efficacy with minimal pediatric experience. Nonspecific esophageal motility disorders are characterized by varying combinations of abnormalities, but the clinical and pathologic relevance of these disorders are not clear.

SECONDARY ESOPHAGEAL MOTILITY DISORDERS

Gastroesophageal reflux disease11 and other inflammatory disorders of the esophagus produce various motor abnormalities. Esophageal motor disorders are also common in other systemic diseases (see Table 393-2) and in children with intestinal pseudoobstruction and esophageal atresia.12,13 Diagnosis and aggressive treatment of the underlying disorder may normalize motility.