Esophageal motility disorder
Encyclopedia
An esophageal motility disorder is a medical
disorder causing difficulty in swallowing
, regurgitation
of food and a spasm
-type pain which can be brought on by an allergic reaction to certain foods and by autoimmune disease affecting the muscles such as myositis.
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.
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 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:
Pathophysiology
The pathophysiology of the primary esophageal motility disorders is poorly defined, with the exception of achalasia. The underlying cause of all the primary motility disorders remains elusive. The secondary motility disorders, such as scleroderma esophagus or esophageal motility disorder of diabetes, are better understood from the standpoint of the preexisting underlying disorders.
LES is thickened, but, microscopically, individual muscle cells are grossly normal.
The physiologic process of achalasia is correlated most directly to the loss of the inhibitory nerves at the sphincter, resulting in failure of the LES to completely relax and causing relative obstruction. Manometry may reveal elevated LES pressure greater than 40 mm Hg in more than 60% of patients; however, hypertensive LES is not universal or required for the manometric diagnosis. The loss of nerves along the esophageal body causes aperistalsis, leading to stasis of ingested food and subsequent dilation of the esophagus. Nonperistaltic isolated contractions or low-amplitude simultaneous contractions of the esophageal body may be observed. If high-amplitude (>60 mm Hg) simultaneous contractions occur, the entity is categorized as vigorous achalasia, which may represent an early stage of classic achalasia. Physiologic characteristics of achalasia are additionally useful in assisting with establishing the diagnosis through chemical challenge testing.
With the partial ganglion cell loss in patients with achalasia, edrophonium (acetylcholine esterase inhibitor) increases LES pressure while atropine (muscarinic antagonist) decreases LES pressure. This characteristic likely explains why the botulinum toxin (acetylcholine release inhibitor) may have therapeutic benefit in patients with achalasia.
Spastic motility disorders of the esophageal body
No documented abnormalities exist regarding the distribution of myenteric neurons in patients diagnosed with spastic motility disorders of the esophageal body, but diffuse fragmentation of vagal filaments, increased endoneural collagen, and mitochondrial fragmentation are described. There appears to be a functional imbalance between excitatory and inhibitory postganglionic pathways, disrupting the coordinated components of peristalsis. In DES, muscular hypertrophy or hyperplasia has been described in the distal two thirds of the esophagus. Muscle wall thickening has been described in patients who are asymptomatic and, conversely, has been absent in some patients with typical symptoms and manometric findings. This controversial finding causes difficulty in attributing symptoms or manometric abnormalities to muscle structure changes. In addition, anxiety states may also play a role in some patients.
In patients with primary motility disorders, results of a physical examination often are unrevealing.
Clinical signs of scleroderma in the proper clinical setting must be noted, especially skin changes. A bedside swallowing challenge may be performed with a glass of water. Check general nutrition and hydration if significant dysphagia is reported. Causes
Primary esophageal motility disorders are idiopathic in nature, but postviral, infectious, environmental, and genetic factors have been hypothesized. See Pathophysiology.
Medicine
Medicine is the science and art of healing. It encompasses a variety of health care practices evolved to maintain and restore health by the prevention and treatment of illness....
disorder causing difficulty in swallowing
Swallowing
Swallowing, known scientifically as deglutition, is the process in the human or animal body that makes something pass from the mouth, to the pharynx, and into the esophagus, while shutting the epiglottis. If this fails and the object goes through the trachea, then choking or pulmonary aspiration...
, regurgitation
Regurgitation (digestion)
Regurgitation is the expulsion of material from the mouth, pharynx, or esophagus, usually characterized by the presence of undigested food or blood.Regurgitation is used by a number of species to feed their young...
of food and a spasm
Spasm
In medicine a spasm is a sudden, involuntary contraction of a muscle, a group of muscles, or a hollow organ, or a similarly sudden contraction of an orifice. It is sometimes accompanied by a sudden burst of pain, but is usually harmless and ceases after a few minutes...
-type pain which can be brought on by an allergic reaction to certain foods and by autoimmune disease affecting the muscles such as myositis.
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 composed 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:
Spastic Esophageal Motility Disorder
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 presbyesophagusPathophysiology
The pathophysiology of the primary esophageal motility disorders is poorly defined, with the exception of achalasia. The underlying cause of all the primary motility disorders remains elusive. The secondary motility disorders, such as scleroderma esophagus or esophageal motility disorder of diabetes, are better understood from the standpoint of the preexisting underlying disorders.
Achalasia
Achalasia is the best defined primary motility disorder and the only one with an established pathology. The predominant neuropathologic process of achalasia involves the loss of ganglion cells from the wall of the esophagus, starting at the LES and developing proximally. The degree of ganglion cell loss parallels the disease duration such that, at 10 years, ganglion cells are likely completely absent. At the LES, the loss of inhibitory nerves is demonstrated by loss of nitric oxide synthase and vasoactive intestinal peptide (VIP) immunohistochemistry staining. Variable amounts of inflammatory cells have been described within the myenteric plexus along with the disappearing nerves. In the peristaltic esophageal body, achalasia is characterized by a loss of intrinsic acetylcholine-containing nerves. Extrinsic nerves may also be affected, characterized by Wallerian degeneration of the axoplasm and myelin sheaths within the vagus nerve and dorsal motor nucleus. Anatomically, the circular muscle layer at theLES is thickened, but, microscopically, individual muscle cells are grossly normal.
The physiologic process of achalasia is correlated most directly to the loss of the inhibitory nerves at the sphincter, resulting in failure of the LES to completely relax and causing relative obstruction. Manometry may reveal elevated LES pressure greater than 40 mm Hg in more than 60% of patients; however, hypertensive LES is not universal or required for the manometric diagnosis. The loss of nerves along the esophageal body causes aperistalsis, leading to stasis of ingested food and subsequent dilation of the esophagus. Nonperistaltic isolated contractions or low-amplitude simultaneous contractions of the esophageal body may be observed. If high-amplitude (>60 mm Hg) simultaneous contractions occur, the entity is categorized as vigorous achalasia, which may represent an early stage of classic achalasia. Physiologic characteristics of achalasia are additionally useful in assisting with establishing the diagnosis through chemical challenge testing.
With the partial ganglion cell loss in patients with achalasia, edrophonium (acetylcholine esterase inhibitor) increases LES pressure while atropine (muscarinic antagonist) decreases LES pressure. This characteristic likely explains why the botulinum toxin (acetylcholine release inhibitor) may have therapeutic benefit in patients with achalasia.
Spastic motility disorders of the esophageal body
No documented abnormalities exist regarding the distribution of myenteric neurons in patients diagnosed with spastic motility disorders of the esophageal body, but diffuse fragmentation of vagal filaments, increased endoneural collagen, and mitochondrial fragmentation are described. There appears to be a functional imbalance between excitatory and inhibitory postganglionic pathways, disrupting the coordinated components of peristalsis. In DES, muscular hypertrophy or hyperplasia has been described in the distal two thirds of the esophagus. Muscle wall thickening has been described in patients who are asymptomatic and, conversely, has been absent in some patients with typical symptoms and manometric findings. This controversial finding causes difficulty in attributing symptoms or manometric abnormalities to muscle structure changes. In addition, anxiety states may also play a role in some patients.
Scleroderma esophagus
In scleroderma, the primary defect in this systemic process is related to smooth muscle atrophy and fibrosis. Esophageal dysmotility develops as the smooth muscle of the esophagus is replaced by scar tissue, gradually leading to progressive loss of peristalsis and a weakening of LES. Motility is preserved at the proximal striated muscle portion of the esophagus.United States
Esophageal motility disorders, excluding achalasia, lack population-based studies. The 2 best-characterized motility disorders, achalasia and DES, represent only a small percentage of diagnosed motility disorders. The incidence of achalasia is 1-3 case per 100,000 population per year.1 As with any other chronic illness, prevalence exceeds incidence significantly. Familial clustering is observed, but a genetic relationship is not established. Nutcracker esophagus is the most common motility disorder (>40% of all motility disorders diagnosed), but it is the most controversial in significance.Mortality/Morbidity
Achalasia is associated with significant and progressive symptomatic discomfort. When advanced, this condition can lead to such severe dysphagia that malnutrition, weight loss, and dehydration can develop. Increased incidence of both esophageal squamous cell and adenocarcinoma is observed in patients with long-standing achalasia. Therapeutic procedures and operations are associated with a small but significant risk of mortality and morbidity. Spastic esophageal motility disorders are associated with symptomatic discomfort but do not lead to the severity of dysphagia observed in patients with achalasia. Chest pain is, in fact, a more common complaint that may precipitate emergency room visits and cardiologic evaluations. Scleroderma esophagus is associated with severe and progressive acid reflux symptoms and complications. Associated complications, including strictures, Barrett esophagus, and adenocarcinoma of the esophagus, are the concern.Race
Racial and environmental differences in the incidence of achalasia and other esophageal motility disorders might be present; however, because of the low incidence of disease and underdiagnosis in developing countries, these differences have not been demonstrated. Racial differences in the incidence of achalasia and other esophageal motility disorders have not been established.Sex
Achalasia affects both sexes in equal numbers. No reliable information for other motility disorders exists.Age
Achalasia commonly presents in the fifth decade but rarely may develop in children as well as in elderly persons.Clinical History
Achalasia Progressive dysphagia for both solids and liquids is the hallmark of achalasia. Dysphagia for solids is more common than for liquids. Retrospectively, symptoms are present on average as long as 6 years prior to presentation. Regurgitation of food retained in the proximal dilated esophagus is a common occurrence, especially at night, requiring patients to sleep using multiple pillows or upright in a chair. This symptom worsens as the esophagus dilates with time. Chest pain may be another early symptom, characterized by a squeezing retrosternal pain radiating to the neck, jaw, arms, or back. The chest pain may worsen with food and can awaken patients from sleep. A sensation of heartburn may be reported by 30% of patients and is assumed to be related to retained food fermentation and lactic acid. Emotional stress or rapid eating may worsen all of the symptoms described above. Weight loss is common with achalasia; however, the loss is usually slight. Spastic esophageal motility disorders Chest pain is the hallmark of spastic esophageal motility disorders, although patients with spastic esophageal motility disorders also may report dysphagia. Similar to the chest pain of achalasia, it may mimic angina. The mechanism is not clear but may be related to transient esophageal muscle ischemia, luminal distension, or altered visceral sensation. Dysphagia is not necessarily related to chest pain. Dysphagia for solids and liquids is a common symptom and especially seen in DES. Dysphagia may be intermittent and nonprogressive in nature, typically not prolonging mealtime or causing weight loss. Patients also commonly report heartburn, regurgitation, or other esophageal complaints of reflux disease due to ineffective acid clearance from the esophagus. Weight loss is common with achalasia; however, the loss is usually slight. Scleroderma esophagus Scleroderma involves the esophagus in more than 75% of patients, regardless of clinical type. Two forms of this disease exist–(1) progressive systemic sclerosis (PSS), characterized by diffuse scleroderma, and a more fulminant form with early involvement of internal organs or (2) CREST syndrome, characterized by calcinosis, Raynaud phenomenon, esophageal dysfunction, sclerodactyly, and telangiectasia. The severity of esophageal involvement does not correlate necessarily with severity of involvement of other organs. In fact, dysphagia may be the presenting clinical symptom in some patients. The esophageal symptoms of scleroderma usually reflect the severity of acid reflux disease, including heartburn, regurgitation, and dysphagia. Erosive esophagitis is observed in as many as 60% of patients, and the incidence of Barrett esophagus and adenocarcinoma of the esophagus is increased. Dysphagia usually is due to diminishing peristalsis, peptic strictures, or a combination of both. PhysicalIn patients with primary motility disorders, results of a physical examination often are unrevealing.
Clinical signs of scleroderma in the proper clinical setting must be noted, especially skin changes. A bedside swallowing challenge may be performed with a glass of water. Check general nutrition and hydration if significant dysphagia is reported. Causes
Primary esophageal motility disorders are idiopathic in nature, but postviral, infectious, environmental, and genetic factors have been hypothesized. See Pathophysiology.
See also
- AchalasiaAchalasiaAchalasia , also known as esophageal achalasia, achalasia cardiae, cardiospasm, and esophageal aperistalsis, is an esophageal motility disorder involving the smooth muscle layer of the esophagus and the lower esophageal sphincter...