Esophageal Motility Disorders
- Article Author:
- Manjeet Goyal
- Article Editor:
- Shivaraj Nagalli
- Updated:
- 10/28/2020 1:51:33 PM
- For CME on this topic:
- Esophageal Motility Disorders CME
- PubMed Link:
- Esophageal Motility Disorders
Introduction
The esophagus is a tubular structure that acts as a conduit to deliver food and other edibles from the mouth to the stomach. This is achieved because of the sequential and well-coordinated movement that propels the food starting from the proximal esophagus all the way towards the distal esophagus and finally into the stomach. Disruption in this well-coordinated movement leads to a spectrum of a disease called esophageal motility disorders and it is categorized into primary and secondary.
Anatomically, it is approximately 25 cm long and is equipped with two sphincters’ one located at the proximal upper part and the second at the distal end. The upper esophageal sphincter (UES) is made up of striated muscles and prevents air influx into the stomach. The lower esophageal sphincter (LES) is made up of smooth muscles and has baseline tonicity that prevents reflux of gastric content into the esophagus. The esophageal body comprises of 2 muscle types; striated muscles in the proximal part and smooth muscles in the distal part. The transition from skeletal muscles to smooth muscles occurs in mid-esophagus. These muscles are arranged in two perpendicular layers; outer longitudinal and inner circular.[1] The coordinated contraction of these two layers is called peristalsis which primarily propels the intraluminal esophageal content into the stomach.
Etiology
Esophageal motility disorders can be subdivided into two:-
- Primary disorders (due to esophageal diseases per se)
- Secondary phenomena, where esophageal dysfunction is part of more global disease, such as in pseudo-achalasia(tumor, compression,etc.), Chagas disease, and PSS (scleroderma).
The motility disorders can also be classified on the basis of the site of pathology:-
- Oropharyngeal dysphagia (oropharynx is the site)
NEUROMUSCULAR*
Amyotrophic lateral sclerosis (ALS, Lou Gehrig disease)CNS tumors (benign or malignant)Idiopathic UES dysfunctionManometric dysfunction of the UES or pharynx†Multiple sclerosisMuscular dystrophyMyasthenia gravisParkinson diseasePolymyositis or dermatomyositisPostpolio syndromeStrokeThyroid dysfunction
STRUCTURAL
CarcinomaInfections of pharynx or neckOsteophytes and other spinal disordersPrior surgery or radiation therapyProximal esophageal webThyromegalyZenker diverticulum
NEUROMUSCULAR (MOTILITY) DISORDERS
Primary
AchalasiaDistal esophageal spasmHypercontractile (jackhammer) esophagusHypertensive LESNutcracker (high-pressure) esophagus
Secondary
Chagas diseaseReflux-related dysmotilityScleroderma and other rheumatologic disorders
STRUCTURAL (MECHANICAL) DISORDERS
Intrinsic
Carcinoma and benign tumorsDiverticulaEosinophilic esophagitisEsophageal rings and webs (other than Schatzki ring)Foreign bodyLower esophageal (Schatzki) ringMedication-induced stricturePeptic stricture
Extrinsic
Mediastinal massSpinal osteophytesVascular compression
Esophageal dysphagia (mid and lower esophagus is the site)
Dysphagia due to pharyngeal or UES dysfunction can also be included in a discussion of esophageal motor disorders, but this is usually a manifestation of a more global neuromuscular disease process. The major focus of this article will be on the primary motility disorders, particularly achalasia. However, mention will be made of the secondary motility disorders and proximal pharyngoesophageal dysfunction when important unique features exist.
Epidemiology
Estimates of the prevalence of dysphagia among individuals older than 50 years range from 16% to 22%, with most of this related to oropharyngeal dysfunction.
Most oropharyngeal dysphagia is related to neuromuscular disease; the prevalence of the most common anatomic etiology, Zenker diverticulum, is estimated to range from a meager 0.01% to 0.11% of the population in the USA, with a peak incidence in men between the 7th and 9th decades.[2] The consequences of oropharyngeal dysphagia aresevere: dehydration, malnutrition, aspiration, choking, pneumonia, and death. Within health care institutions, it is estimated that up to 13% of hospitalized patients and 60% of nursing home residents have feeding problems and, again, most are attributed to oropharyngeal dysfunction as opposed to esophageal dysfunction.
Mortality of nursing residents with dysphagia and aspiration can be as high as 45% over 1 year. As the U.S. population continues to age, oropharyngeal dysphagia will become an increasing problem associated with complex medical and ethical issues.
Achalasia is the most easily recognized and best-defined motor disorder of the esophagus. Modern estimates of the incidence of achalasia are about 2.9 per 100,000 population in the USA[3] affecting both genders equally and usually presenting between 25 and 60 years of age.[4] As achalasia is a chronic condition, its prevalence greatly exceeds its incidence; a recent estimate of achalasia prevalence in Chicago concluded that it may be as high as 76 per 100,000 population, given that the average age of diagnosis was 56 with an expectedaverage survival of 26 years after diagnosis.42 Reports of familial clustering of achalasia raise the possibility of genetic predisposition. However, arguing against a strong genetic determinant, a survey of 1012 first-degree relatives of 159 achalasics identified no affected relatives. There is a rare genetic achalasia syndrome associated with adrenal insufficiency and alacrima. This syndrome is inherited as an autosomal recessive disease and manifests with the childhood-onset of autonomic nervous system dysfunction including achalasia, alacrima, sinoatrial dysfunction, abnormal pupillary responses to light, and delayed gastric emptying.[5] It is caused by mutations in AAAS, which encodes a protein known as ALADIN.There are no population-based studies on the incidence or prevalence of esophageal motility disorders other than achalasia. Thus, the only way to estimate the incidence or prevalence of spastic disorders is to examine data on populations at risk and reference the observed frequency of spastic disorders to the incidence of achalasia, which, as detailed earlier, is about 2.75 per 100,000 population. In doing so, the prevalence of DES is much lower than that if modern restrictive diagnostic criteria are used.
Populations at risk for motility disorders are patients with chest pain and/or dysphagia, so it is among these patients that extensive manometric data have been collected. Manometric abnormalities are prevalent among these groups, but in most cases, the manometric findings are of unclear significance.
Pathophysiology
Similar to the etiology, the pathophysiology of esophageal motility disorder is very hazy with the exception of achalasia. This is applicable to all primary esophageal disorders. For secondary esophageal motility disorders, esophageal pathology is better explained in the context of pre-existing underlying illness.
Achalasia
It is the only primary esophageal pathology that has slightly well-known pathophysiology among all the other primary esophageal dysmotility disorders. It is characterized by impaired LES relaxation with swallowing and a peristalsis in the smooth muscle esophagus. If there are premature, spastic contractions in the esophageal body, the disease is referred to as spastic (type III) achalasia. These physiologic alterations result from damage to the innervation of the smooth muscle segment of the esophagus (including the LES) with loss of ganglion cells within the myenteric (Auerbach) plexus. Several observers report fewer ganglion cells and ganglion cells surrounded by mononuclear inflammatorycells in the smooth muscle esophagus of achalasics.55 The degree of ganglion cell loss parallels the duration of disease, likely progressing from EGJ outflow obstruction to type II achalasia, to type I achalasia, to end-stage achalasia.55,56 Type III achalasia seems to have unique pathogenesis, characterized by myenteric plexus inflammation and altered function, but not destruction.55 Physiologic studies in achalasics suggest dysfunction consistent with postganglionic denervation of esophageal smooth muscle potentially affect excitatory ganglion neurons (cholinergic), inhibitory ganglion neurons (NO ± VIP), or both (see Fig. 44.4). Regardless of excitatory ganglion neuron impairment, it is clearthat inhibitory ganglion neuron dysfunction is an early manifestation of achalasia. These neurons mediate deglutitive inhibition (including LES relaxation) and the sequenced propagation of esophageal peristalsis. The ultimate cause of ganglion cell degeneration in idiopathic achalasia is gradually being unraveled, with increasing evidencepointing toward an autoimmune process in genetically susceptible individuals.59 HSV-1 has been proposed to be one of the causes of ganglion destruction
Distal Esophageal Spasm (DES)
Although the diagnosis of DES is often invoked as a cause of esophageal chest pain, the entity is actually exceedingly rare with most cases of esophageal chest pain attributable to reflux disease or achalasia. Chicago Classification has proposed reduced distal latency (DL) of peristalsis as the cardinal abnormality in DES. Although DES is clearly a disorder of peristalsis, the majority of afflicted patients exhibit normal peristaltic contractions most of the time. The neuromuscular pathology responsible for DES isunknown and there are no known risk factors. The most striking reported pathologic change is of diffuse muscular hypertrophy or hyperplasia in the distal esophagus with a thickening of up to 2cm.
Hypercontractile (Jackhammer) Esophagus
Vigorous esophageal contractions with normal DL defined as esophageal hypercontractility or jackhammer esophagus in the Chicago Classification can be associated with both dysphagia and chest pain. From a clinical perspective, the summary metric for quantifying distal esophageal contractility in High-Resolution Manometry is the distal contractileintegral (DCI). DCI values greater than 8000 mm Hg•cm•sec represent an extreme pattern of hypercontractility, often associated with repetitive contractions, rarely seen in normal subjects, and almost always associated with chest pain and dysphagia. The current version of the Chicago Classification labels this condition “jackhammer esophagus” when 2 such contractions occur in a manometric study.64,65?
Absent Peristalsis
It is often idiopathic.
Spastic Motility Disorder
It is characterized by extensive degeneration of vagus nerve filaments, excessive deposition of collagenous material around nerve endings and fragmentation of mitochondria. This leads to an imbalance between excitatory and inhibitory impulses in the postganglionic pathways. This is more marked in the distal two-thirds of the esophagus. It is also believed that anxiety also has a role in its pathogenesis[6].
Scleroderma
Owing to the propensity of patients with scleroderma to have excessive deposition of fibrous tissue in various organs, esophagus also has atrophic and fibrous changes occurring. The muscular layer of the esophagus is gradually replaced by the fibrous scar tissue which gradually leads to loss of peristalsis and weakening of LES. However, this phenomenon is only limited to the distal esophagus and the motility at the proximal end is preserved.[7]
Evaluation
Once esophageal motility disorder is suspected in a patient, there is a series of investigations that can be performed. There is no particular order in which they have to be performed rather it is the physician’s discretion, clinical experience and it varies from case to case. Generally, similar to approaching any other illness, a non-invasive investigation is chosen.
Esophagraphy: An esophagography is usually chosen as a first investigation that shows the anatomical and physiological functioning of the esophagus.
In advanced achalasia, there may be a dilated intrathoracic esophagus with an air-fluid level. There may be a tapering of the esophagus at the lower esophagus which gives a pathognomonic appearance of a “bird beak”. In early achalasia, there may be normal anatomy but the loss of peristalsis will be reflected by the pooling of contrast. In some instances, an epinephric diverticula may be noted immediately above the lower esophageal sphincter (LES).[8]
In patients who have achalasia, there is a 10-20% chance that these patients have concurrent hiatal hernia.
In DES, esophagogram may show classic “corkscrew” or “rosary bead” appearance of the esophagus. Scleroderma esophagogram shows dilated esophagus, reflux, and weak or absent peristalsis.
Manometry
- Achalasia: In patients with achalasia, manometry demonstrates hallmark findings of aperistalsis in the esophageal body and failure of LES to relax.[9] In 90% of the cases, the diagnosis of achalasia can be made using these criteria but in a small subset, approximately 10% of patients, the manometry is inconclusive due to the inability to correctly place the catheter across LES.
- Spastic Esophageal Motility disorders:
- DES: It is characterized by normal peristalsis but simultaneous contractions of >30% of water swallows. Other associated findings include repetitive (>2 peaks), prolonged (>6 s), and high amplitude (>180mmHg) contractions.[ Reproducibility of axial force and manometric recordings in the esophagus during wet and dry swallows.] it is also characterized by failure of LES to relax fully and abnormally high LES pressure (>40mmHg).[10]
- Nutcracker Esophagus: It has normal pattern peristalsis with high amplitude contractions >180mmHg with repetitive (>2 peaks), prolonged (>6 s) contractions, and high LES pressure (>40mmHg) on manometry.
High-Resolution Manometry
In recent advancements, high-resolution manometry is used which is superior to conventional investigation in identifying the esophageal disease.[11]This technique is proven to be much faster and can accurately diagnose different esophageal motility pathology that can be categorized based on anatomical site.[9]
Endoscopy
It is the only investigation tool that has both, diagnostic and therapeutic significance while managing esophageal motility disorders. It may be inconclusive in early disease because gross abnormalities are usually appreciable in the later part of the disease course.[12]
Stasis of food inside the esophageal lumen can be appreciated on endoscopy and may be seen as inflamed, eroded, ulcerated, erythematous or friable mucosa. Biopsies can be taken at the time and be sent for histopathological diagnosis or an endoscopic intervention be done at the same time.
Treatment / Management
Patients with suspected esophageal motility disorders should be dealt with at a center with expert gastroenterology and surgical services.
- Medical care: The primary pathology in achalasia is irreversible and incurable, therefore the mainstay of treatment is symptomatic control when the disease is mild to moderate.[13] From the intervention point of view, surgical and endoscopic therapies are also available that can provide relief for a considerable amount of time.
- Pharmacological interventions: With medicines, patients achieve good symptomatic control particularly when the disease is in the early stages. Nitrates have been used historically along with nifedipine to control esophageal motility disorders. Other drugs used with limited efficacy are anticholinergics, theophylline, beta-2 agonists, phosphodiesterase inhibitors and nitroglycerin. For predominant heartburn and reflux symptoms, gastroprokinetic and proton pump inhibitors (PPIs) are used. If an element of anxiety is also evident from history and clinical encounter, the use of low dose tricyclic antidepressants (TCAs) or selective serotonin reuptake inhibitors (SSRIs) are also used.
- Endoscopic Therapy: Esophagogastroduodenoscopy (EGD) is performed which can identify the exact anatomic site of narrowing. Dilation can be achieved with multiple techniques but two widely used and comparatively less invasive techniques are:
- Use of TTS pneumatic balloon
- Use of EndoFlip dilation system
These can be done under general anesthesia or sedation and adequate analgesia. The patient may experience chest pain, worsening of heartburn and reflux.
Another technique that can be employed while doing the EGD is the injection of botulinum toxin at the LES or at the site of narrowing. This is normally used for patients who are poor surgical candidates or their disease is refractory to medical management.
- Surgical care: With the same principle as balloon dilatation, surgical interventions are targeted at the LES to release the high pressure at the esophagogastric junction (EGJ).[14] There are three evidence-based surgical interventions that are available for refractory or severe cases.[15] These procedures are:
- Heller’s myotomy
- Extended heller myotomy
- Esophagectomy with gastric pull-up or intestinal interposition.
Differential Diagnosis
Differential diagnosis entirely depends on the presenting symptoms, but generally, when a patient presents with chest pain, cardiac workup should be immediately done to rule out coronary artery disease. While suspecting esophageal motility disorders, the following differential diagnosis can be made and must be ruled out:
- Coronary artery disease (CAD)
- Chagas disease
- Pseudoachalasia
- Diffuse esophageal spasm
- Hypercontractile esophagus
- Xerostomia
- Globus sensation
The major objectives of history are to differentiate oropharyngeal dysphagia from esophageal dysphagia, xerostomia (hyposalivation), or globus sensation.
Globus sensation, in particular, is frequently confused with dysphagia. Unlike dysphagia, which occurs only during swallowing, globus sensation is prominent between swallows.
Patients relate the nearly constant sensation of having a lump in their throat or feeling a foreign object caught in their throat. In some instances, globus is associated with reflux symptoms, and in others with substantial anxiety. It is the linkage with anxiety that led to the older nomenclature “globus hystericus.”
Unfortunately, studies have failed to define an objective anatomic or physiologic cause for globus, and we are left with the crucial data being in the history; globus sensation persists regardless of the act of swallowing
Prognosis
Achalasia: It is a progressive disease which means that it requires chronic therapy and endoscopic or surgical intervention and reintervention. Patients may be required to be watchful about their dietary habits despite being on or after treatment.
Scleroderma esophagus: The severity of the esophageal disease depends on how well the primary illness is well controlled. Since scleroderma is a progressive illness, patients present with significant acid reflux.
Spastic esophageal disorders: Generally, it has a very favorable prognosis and patients usually attain good baseline status. Worsening usually warrants workup as these disorders have a propensity to develop into achalasia.
Complications
In patients suffering from achalasia, there is usually a higher risk of developing squamous cell carcinoma as compared to the general population but this has not been proven by sound scientific evidence. It is hypothesized that it is because of chronic mucosal irritation.
Deterrence and Patient Education
Patients should be counseled regarding the chronicity of this disease. They should have a detailed discussion with the clinician regarding therapeutic options, management outcomes, dietary and lifestyle modifications.
Enhancing Healthcare Team Outcomes
Important members of the healthcare team for patients with esophageal motility disorders include primary care providers, gastroenterologists, manometry nurses/techs, and surgeons. PCPs must help us in identifying patients that may be potentially suffering from dysphagia. Nurses and techs are trained to perform motility testing. Gastroenterologists and esophageal surgeons can interpret the results of testing, and treat as an interprofessional team depending on the outcome.