Failing deglutitive inhibition in primary esophageal motility disorders

Role of mechanoregulation in mast cell-mediated immune inflammation of the smooth muscle in the pathophysiology of esophageal motility disorders

Major esophageal disorders involve obstructive transport of bolus to the stomach, causing symptoms of dysphagia and impaired clearing of the refluxed gastric contents. These may occur due to mechanical constriction of the esophageal lumen or loss of relaxation associated with deglutitive inhibition, as in achalasia-like disorders. Recently, immune inflammation has been identified as an important cause of esophageal strictures and the loss of inhibitory neurotransmission. These disorders are also associated with smooth muscle hypertrophy and hypercontractility, whose cause is unknown. This review investigated immune inflammation in the causation of smooth muscle changes in obstructive esophageal bolus transport. Findings suggest that smooth muscle hypertrophy occurs above the obstruction and is due to mechanical stress on the smooth muscles. The mechanostressed smooth muscles release cytokines and other molecules that may recruit and microlocalize mast cells to smooth muscle bundles, so that their products may have a close bidirectional effect on each other. Acting in a paracrine fashion, the inflammatory cytokines induce genetic and epigenetic changes in the smooth muscles, leading to smooth muscle hypercontractility, hypertrophy, and impaired relaxation. These changes may worsen difficulty in the esophageal transport. Immune processes differ in the first phase of obstructive bolus transport, and the second phase of muscle hypertrophy and hypercontractility. Moreover, changes in the type of mechanical stress may change immune response and effect on smooth muscles. Understanding immune signaling in causes of obstructive bolus transport, type of mechanical stress, and associated smooth muscle changes may help pathophysiology-based prevention and targeted treatment of esophageal motility disorders.NEW & NOTEWORTHY Esophageal disorders such as esophageal stricture or achalasia, and diffuse esophageal spasm are associated with smooth muscle hypertrophy and hypercontractility, above the obstruction, yet the cause of such changes is unknown. This review suggests that smooth muscle obstructive disorders may cause mechanical stress on smooth muscle, which then secretes chemicals that recruit, microlocalize, and activate mast cells to initiate immune inflammation, producing functional and structural changes in smooth muscles. Understanding the immune signaling in these changes may help pathophysiology-based prevention and targeted treatment of esophageal motility disorders.

Multiple Sclerosis Is Associated With Achalasia and Diffuse Esophageal Spasm

Background/Aims

Multiple sclerosis (MS) is an inflammatory disease characterized by the demyelination of primarily the central nervous system. Diffuse esophageal spasm (DES) and achalasia are both disorders of esophageal peristalsis which cause clinical symptoms of dysphagia. Mechanisms involving dysfunction of the pre- and post-ganglionic nerve fibers of the myenteric plexus have been proposed. We sought to determine whether MS confers an increased risk of developing achalasia or DES.

Methods

Cohort analysis was done using the Explorys database. Univariate logistic regression was performed to determine the odds MS confers to each motility disorder studied. Comparison of proportions of dysautonomia comorbidities was performed among the cohorts. Patients with a prior diagnosis of diabetes mellitus, chronic Chagas' disease, opioid use, or CREST syndrome were excluded from the study.

Results

Odds of MS patients developing achalasia or DES were (OR, 2.09; 95% CI, 1.73-2.52; P < 0.001) and (OR, 3.15; 95% CI, 2.89-3.42; P < 0.001), respectively. In the MS/achalasia cohort, 27.27%, 18.18%, 9.09%, and 45.45% patients had urinary incontinence, gastroparesis, impotence, and insomnia, respectively. In the MS/DES cohort, 35.19%, 11.11%, 3.70%, and 55.56% had these symptoms. In MS patients without motility disorders, 12.64%, 0.79%, 2.21%, and 21.85% had these symptoms.

Conclusions

Patients with MS have higher odds of developing achalasia or DES compared to patients without MS. MS patients with achalasia or DES have higher rates of dysautonomia comorbidities. This suggests that these patients have a more severe disease phenotype in regards to the extent of neuronal degradation and demyelination causing the autonomic dysfunction.

Why so Many Patients With Dysphagia Have Normal Esophageal Function Testing

Esophageal peristalsis involves a sequential process of initial inhibition (relaxation) and excitation (contraction), both occurring from the cranial to caudal direction. The bolus induces luminal distension during initial inhibition (receptive relaxation) that facilitates smooth propulsion by contraction travelling behind the bolus. Luminal distension during peristalsis in normal subjects exhibits unique characteristics that are influenced by bolus volume, bolus viscosity, and posture, suggesting a potential interaction between distension and contraction. Examining distension-contraction plots in dysphagia patients with normal bolus clearance, ie, high-amplitude esophageal peristaltic contractions, esophagogastric junction outflow obstruction, and functional dysphagia, reveal 2 important findings. Firstly, patients with type 3 achalasia and nonobstructive dysphagia show luminal occlusion distal to the bolus during peristalsis. Secondly, patients with high-amplitude esophageal peristaltic contractions, esophagogastric junction outflow obstruction, and functional dysphagia exhibit a narrow esophageal lumen through which the bolus travels during peristalsis. These findings indicate a relative dynamic obstruction to bolus flow and reduced distensibility of the esophageal wall in patients with several primary esophageal motility disorders. We speculate that the dysphagia sensation experienced by many patients may result from a normal or supernormal contraction wave pushing the bolus against resistance. Integrating representations of distension and contraction, along with objective assessments of flow timing and distensibility, complements the current classification of esophageal motility disorders that are based on the contraction characteristics only. A deeper understanding of the distensibility of the bolus-containing esophageal segment during peristalsis holds promise for the development of innovative medical and surgical therapies to effectively address dysphagia in a substantial number of patients.

Effect of inter-swallow interval on striated esophagus peristalsis; a comparative study with smooth muscle esophagus

BACKGROUND

Effect of inter-swallow interval on the contractility of smooth muscle esophagus is well-documented. However, the effects on peristalsis of the striated esophagus have not been systematically studied. A better understanding of striated esophagus motor function in health and disease may enhance the interpretation of manometric studies and inform clinical care. The aim of this study was to assess the effect of inter-swallow interval on striated esophagus compared to findings with that of the smooth muscle esophagus.

METHODS

We performed two sets of studies to (1) determine the effect of various inter-swallow interval in 20 healthy volunteers and (2) assess the effect of ultra-short swallow intervals facilitated by straw drinking in 28 volunteers. We analyzed variables using ANOVA with Tukey's pairwise comparison and paired t-test.

KEY RESULTS

Unlike smooth muscle esophagus, the striated esophagus contractile integral did not change significantly for swallow intervals ranging from 30 to 5 s. On the contrary, striated esophagus demonstrated absent or reduced peristalsis in response to ultra-short (<2 s) intervals during straw-facilitated multiple rapid swallows.

CONCLUSIONS AND INFERENCES

Striated esophagus peristalsis is subject to manometrically observed inhibition during swallows with ultra-short intervals. Inter-swallow intervals as short as 5 s that inhibit smooth muscle esophagus peristalsis do not inhibit striated muscle peristalsis. The mechanisms of these observations are unknown but may relate to central or myenteric nervous system influences or the effects of pharyngeal biomechanics.

Distension contraction plots of pharyngeal/esophageal peristalsis: next frontier in the assessment of esophageal motor function

Esophageal peristalsis consists of initial inhibition (relaxation) followed by excitation (contraction), both of which move sequentially in the aboral direction. Initial inhibition results in receptive relaxation and bolus-induced luminal distension, which allows propulsion by the contraction with minimal resistance to flow. Similar to the contraction wave, luminal distension has unique waveform characteristics in normal subjects; both are modulated by bolus volume, bolus viscosity, and posture, suggesting a possible cause-and-effect relationship between the two. Distension contraction plots in patients with dysphagia with normal bolus clearance [high-amplitude esophageal contractions (HAECs), esophagogastric junction outflow obstruction (EGJOO), and functional dysphagia (FD)] reveal two major findings: 1) unlike normal subjects, there is luminal occlusion distal to bolus during peristalsis in certain patients, i.e., with type 3 achalasia and nonobstructive dysphagia; and 2) bolus travels through a narrow lumen esophagus during peristalsis in patients with HAECs, EGJOO, and FD. Aforementioned findings indicate a relative dynamic obstruction to the bolus flow during peristalsis and reduced distensibility of esophageal wall in the bolus segment of the esophagus. We speculate that a normal or supernormal contraction wave pushing bolus against resistance is the mechanism of dysphagia sensation in significant number of patients. Representations of distension and contraction, combined with objective measures of flow timing and distensibility are complementary to the current scheme of classifying esophageal motility disorders based solely on the characteristics of contraction phase of peristalsis. Better understanding of the distensibility of the bolus-containing segment of the esophagus during peristalsis will lead to the development of novel medical and surgical therapies in the treatment of dysphagia in significant number of patients.

Achalasia

Achalasia is a rare disorder of the oesophageal smooth muscle characterized by impaired relaxation of the lower oesophageal sphincter (LES) and absent or spastic contractions in the oesophageal body. The key pathophysiological mechanism is loss of inhibitory nerve function that probably results from an autoimmune attack targeting oesophageal myenteric nerves through cell-mediated and, possibly, antibody-mediated mechanisms. Achalasia incidence and prevalence increase with age, but the disorder can affect all ages and both sexes. Cardinal symptoms consist of dysphagia, regurgitation, chest pain and weight loss. Several years can pass between symptom onset and an achalasia diagnosis. Evaluation starts with endoscopy to rule out structural causes, followed by high-resolution manometry and/or barium radiography. Functional lumen imaging probe can provide complementary evidence. Achalasia subtypes have management and prognostic implications. Although symptom questionnaires are not useful for diagnosis, the Eckardt score is a simple symptom scoring scale that helps to quantify symptom response to therapy. Oral pharmacotherapy is not particularly effective. Botulinum toxin injection into the LES can temporize symptoms and function as a bridge to definitive therapy. Pneumatic dilation, per-oral endoscopic myotomy and laparoscopic Heller myotomy can provide durable symptom benefit. End-stage achalasia with a dilated, non-functioning oesophagus may require oesophagectomy or enteral feeding into the stomach. Long-term complications can, rarely, include oesophageal cancer, but surveillance recommendations have not been established.

[Chicago Classification ver. 4.0: Diagnosis of Peristaltic Disorder]

The Chicago Classification is being revised continuously for the accurate diagnosis of esophageal peristaltic disorders in which the etiology is unclear, and the disease behavior is heterogeneous. The ver. 4.0 was recently updated. A representative change in the diagnosis of esophageal peristaltic disorders of the ver. 4.0 showed that the distinction between major and minor disorders was eliminated and was divided into the following four diagnoses: absent contractility, distal esophageal spasm (DES), hypercontractile esophagus (HE), and ineffective esophageal motility. Compared to the ver. 3.0, it recommended a more detailed protocol of high-resolution esophageal manometry and methods of interpreting manometric. In addition, it emphasized the clinically relevant symptoms in diagnosing DES and HE, and presented provocative tests (e.g., multiple rapid swallow and rapid drinking challenge), as well as additional testing, including impedance, timed barium esophagogram and functional lumen imaging probe, which may provide more standardized and rigorous criteria for peristaltic patterns and to minimize the ambiguity in diagnosis. Although it will take time and effort to apply this revised Chicago Classification in clinical practice, it may help diagnose and manage patients with esophageal peristalsis disorder in the future.

Rhythmic contraction but arrhythmic distension of esophageal peristaltic reflex in patients with dysphagia

Background

Reason for dysphagia in a significant number of patients remains unclear even after a thorough workup. Each swallow induces esophageal distension followed by contraction of the esophagus, both of which move sequentially along the esophagus. Manometry technique and current system of classifying esophageal motility disorders (Chicago Classification) is based on the analysis of the contraction phase of peristalsis.

Goal

Whether patients with unexplained dysphagia have abnormalities in the distension phase of esophageal peristalsis is not known.

Methods

Using Multiple Intraluminal esophageal impedance recordings, which allow determination of the luminal cross-sectional area during peristalsis, we studied patients with nutcracker esophagus (NC), esophagogastric junction outflow obstruction (EGJOO), and functional dysphagia (FD).

Results

Distension contraction plots revealed that swallowed bolus travels significantly faster through the esophagus in all patient groups as compared to normals. The luminal cross-sectional area (amplitude of distension), and the area under the curve of distension were significantly smaller in patients with NC, EGJOO, and FD as compared to normals. Bolus traverses the esophagus in the shape of an “American Football” in normal subjects. On the other hand, in patients the bolus flow was fragmented. ROC curves revealed that bolus flow abnormalities during peristalsis are a sensitive and specific marker of dysphagia.

Conclusion

Our findings reveal abnormality in the distension phase of peristalsis (a narrow lumen esophagus) in patients with dysphagia. We propose that the esophageal contraction forcing the swallowed bolus through a narrow lumen esophagus is the cause of dysphagia sensation in patients with normal contraction phase of peristalsis.

Distension-contraction profile of peristalsis in patients with nutcracker esophagus

INTRODUCTION

High amplitude peristaltic esophageal contractions, that is, nutcracker esophagus, were originally described in association with "angina-like pain" of esophageal origin. However, significant number of nutcracker patients also suffer from dysphagia. High-resolution esophageal manometry (HRM) assesses only the contraction phase of peristalsis. The degree of esophageal distension during peristalsis is a surrogate of relaxation and can be measured from the intraluminal esophageal impedance measurements.

AIMS

Determine the amplitude of distension and temporal relationship between distension and contraction during swallow-induced peristalsis in nutcracker patients.

METHODS

HRM impedance (HRMZ) studies were performed and analyzed in 24 nutcracker and 30 normal subjects in the Trendelenburg position. A custom-built software calculated the numerical data of the amplitudes of distension and contraction, the area under the curve (AUC) of distension and contraction, and the temporal relationship between distension and contraction.

RESULTS

In normal subjects, the distension peaks similar to contraction traverse sequentially the esophagus. The amplitude of contraction is greater in the nutcracker esophagus but the amplitude of distension and area under the curve of distension are smaller in patients compared to controls. Distension peaks are aligned closely with contraction in normal subjects, but in patients, the bolus travels faster to the distal esophagus, resulting in a smaller time interval between the onset of swallow and distension peak. Receiver operative characteristics (ROC) curve reveals high sensitivity and specificity of the above parameters in patients.

CONCLUSION

Abnormalities in the distension phase of peristalsis are a possible mechanism of dysphagia in patients with nutcracker esophagus.

Chicago Classification Update (v4.0): Technical review on diagnostic criteria for distal esophageal spasm

Distal esophageal spasm (DES) is defined as a manometric pattern of at least 20% of premature contractions in a context of normal esophago-gastric junction relaxation in a patient with dysphagia or non-cardiac chest pain. The definition of premature contraction requires the measurement of the distal latency and identification of the contractile deceleration point (CDP). The CDP can be difficult to localize, and alternative methods are proposed. Further, it is important to differentiate contractile activity and intrabolus pressure. Multiple rapid swallows are a useful adjunctive test to perform during high-resolution manometry to search for a lack of inhibition that is encountered in DES. The clinical relevance of the DES-manometric pattern was raised as it can be secondary to treatment with opioids or observed in patients referred for esophageal manometry before antireflux surgery in absence of dysphagia and non-cardiac chest pain. Further idiopathic DES is rare, and one can argue that when encountered, it could be part of type III achalasia spectrum. Medical treatment of DES can be challenging. Recently, endoscopic treatments with botulinum toxin and peroral endoscopic myotomy have been evaluated, with conflicting results while rigorously controlled studies are lacking. Future research is required to determine the role of contractile vigor and lower esophageal sphincter hypercontractility in the occurrence of symptoms in patients with DES. The role of impedance-combined high-resolution manometry also needs to be evaluated.

Rapid activation of esophageal mechanoreceptors alters the pharyngeal phase of swallow: Evidence for inspiratory activity during swallow

Swallow is a complex behavior that consists of three coordinated phases: oral, pharyngeal, and esophageal. Esophageal distension (EDist) has been shown to elicit pharyngeal swallow, but the physiologic characteristics of EDist-induced pharyngeal swallow have not been specifically described. We examined the effect of rapid EDist on oropharyngeal swallow, with and without an oral water stimulus, in spontaneously breathing, sodium pentobarbital anesthetized cats (n = 5). Electromyograms (EMGs) of activity of 8 muscles were used to evaluate swallow: mylohyoid (MyHy), geniohyoid (GeHy), thyrohyoid (ThHy), thyropharyngeus (ThPh), thyroarytenoid (ThAr), cricopharyngeus (upper esophageal sphincter: UES), parasternal (PS), and costal diaphragm (Dia). Swallow was defined as quiescence of the UES with overlapping upper airway activity, and it was analyzed across three stimulus conditions: 1) oropharyngeal water infusion only, 2) rapid esophageal distension (EDist) only, and 3) combined stimuli. Results show a significant effect of stimulus condition on swallow EMG amplitude of the mylohyoid, geniohyoid, thyroarytenoid, diaphragm, and UES muscles. Collectively, we found that, compared to rapid cervical esophageal distension alone, the stimulus condition of rapid distension combined with water infusion is correlated with increased laryngeal adductor and diaphragm swallow-related EMG activity (schluckatmung), and post-swallow UES recruitment. We hypothesize that these effects of upper esophageal distension activate the brainstem swallow network, and function to protect the airway through initiation and/or modulation of a pharyngeal swallow response.

Hypercontractile Esophagus From Pathophysiology to Management: Proceedings of the Pisa Symposium

Hypercontractile esophagus (HE) is a heterogeneous major motility disorder diagnosed when ≥20% hypercontractile peristaltic sequences (distal contractile integral >8,000 mm Hg*s*cm) are present within the context of normal lower esophageal sphincter (LES) relaxation (integrated relaxation pressure < upper limit of normal) on esophageal high-resolution manometry (HRM). HE can manifest with dysphagia and chest pain, with unclear mechanisms of symptom generation. The pathophysiology of HE may entail an excessive cholinergic drive with temporal asynchrony of circular and longitudinal muscle contractions; provocative testing during HRM has also demonstrated abnormal inhibition. Hypercontractility can be limited to the esophageal body or can include the LES; rarely, the process is limited to the LES. Hypercontractility can sometimes be associated with esophagogastric junction (EGJ) outflow obstruction and increased muscle thickness. Provocative tests during HRM can increase detection of HE, reproduce symptoms, and predict delayed esophageal emptying. Regarding therapy, an empiric trial of a proton pump inhibitor, should be first considered, given the overlap with gastroesophageal reflux disease. Calcium channel blockers, nitrates, and phosphodiesterase inhibitors have been used to reduce contraction vigor but with suboptimal symptomatic response. Endoscopic treatment with botulinum toxin injection or pneumatic dilation is associated with variable response. Per-oral endoscopic myotomy may be superior to laparoscopic Heller myotomy in relieving dysphagia, but available data are scant. The presence of EGJ outflow obstruction in HE discriminates a subset of patients who may benefit from endoscopic treatment targeting the EGJ.

Biomechanical correlates of sequential drinking behavior in aging

BACKGROUND

The timed water swallow test (TWST) is a test of sequential swallowing where a measured volume is ingested as quickly as comfortably possible. We undertook a study of the biomechanics underpinning the TWST in healthy young and older participants.

METHODS

Thirty healthy volunteers underwent high-resolution impedance manometry (MMS; Unisensor, 2.7 mm diameter, 32 pressure sensors, 16 impedance segments). Participants were asked to drink 150 mL, 0.9% normal saline solution rapidly. Swallowing biomechanics and bolus flow characteristics were assessed using pressure-flow analysis and compared using t test and Fisher's exact test with significance as P < .05.

KEY RESULTS

Older participants (n = 18; 76 ± 11 years) took longer to complete the TWST (21.2 ± 2.5 vs 9.2 ± 1.0 seconds; P < .001) and displayed reduced volume per swallow (16.6 ± 1.3 vs 27.8 ± 2.9 mL; P < .001) compared to younger participants (n = 12; 29 ± 5 years). Two distinctive pharyngeal swallowing patterns were observed: (a) a single rapid sequence of swallows with or without a clearing swallow (Pattern I) or (b) multiple, shorter sequences interrupted and/or interspersed with single swallows or breaks (Pattern II). Some older participants showed biomechanical evidence of upper esophageal sphincter restriction (n = 7) or impaired deglutitive inhibition (n = 7), associated with the more prolonged Pattern II (TWST duration 30.1 ± 1.5 vs Pattern I 11.9 ± 1.5 seconds; P < .001).

CONCLUSIONS AND INFERENCES

Healthy older participants had an increased duration of TWST, suggesting a need to adapt normative values for this population. Rapid sequential swallowing was associated with evidence of UES restriction and impaired deglutitive inhibition in some older participants.

Response to multiple rapid swallows shows impaired inhibitory pathways in distal esophageal spasm patients with and without concomitant esophagogastric junction outflow obstruction

Distal esophageal spasm (DES) is a motility disorder characterized by premature contraction of the esophageal body during single swallows. It is thought to be due to impairment of esophageal inhibitory pathways, but studies to support this are limited. The normal response to multiple rapid swallows (MRS) is deglutitive inhibition of the esophageal body during the MRS sequence. Our aim was to compare the response to MRS in DES patients and healthy control subjects. Response to MRS during HRM was evaluated in 19 DES patients (8 with and 11 without concomitant esophagogastric junction outflow obstruction [EGJOO]) and 24 asymptomatic healthy controls. Patients with prior gastroesophageal surgery, peroral endoscopic myotomy, pneumatic dilation, esophageal botulinum toxin injection within 6 months of HRM, opioid medication use, and esophageal stricture were excluded. Response to MRS was evaluated for complete versus impaired inhibition (esophageal body contractility with distal contractile integral [DCI] > 100 mmHg-sec-cm during MRS), presence of post-MRS contraction augmentation (DCI post MRS greater than single swallow mean DCI), and integrated relaxation pressure (IRP). Impaired deglutitive inhibition during MRS was significantly more frequent in DES compared to controls (89% vs. 0%, P < 0.001), and frequency was similar for DES with versus without concomitant EGJOO (100% vs. 82%, P = 0.48). The proportion of subjects with augmentation post MRS was similar for both groups (37% vs. 38%, P = 1.00), but mean DCI post MRS was higher in DES than controls (3360.0 vs. 1238.9, P = 0.009). IRP was lower during MRS compared to single swallows in all patients, and IRP during MRS was normal in 5 of 8 patients with DES and EGJOO. Our study suggests that impaired deglutitive inhibition during MRS is present in the majority of patients with DES regardless of whether they have concomitant EGJOO, and future studies should explore the usefulness of incorporating response to MRS in the diagnosis of DES.

Relationship between distension-contraction waveforms during esophageal peristalsis: effect of bolus volume, viscosity, and posture

High-resolution esophageal manometry (HRM) in its current form assesses only the contraction phase of peristalsis. Degree of esophageal distension ahead of contraction is a surrogate of relaxation and can be measured from intraluminal esophageal impedance measurements. The characteristics of esophageal contractions, i.e., their amplitude, duration, velocity, and modulating factors, have been well studied. We studied the effect of bolus volume and viscosity and posture on swallow-induced distension and contraction and the temporal relationship between the two. HRM impedance recordings of 50 healthy subjects with no esophageal symptoms were analyzed. Eight to ten swallows of 5 and 10 mL of 0.5 N saline and a viscous bolus were recorded in the supine and Trendelenburg positions. Custom-built computer software generated the distension-contraction plots and numerical data of the amplitudes of distension (cross-sectional area) and contraction, and the temporal relationship between distension and peak contraction. The hallmarks of distension waveforms are that 1) distension peak, similarly to contraction, travels the esophagus in a peristaltic fashion, and the amplitude of distension increases from the proximal-to-distal direction; 2) the amplitude of distension is greater with 10 mL than with 5 mL and greater in Trendelenburg than in supine posture; and 3) bolus viscosity increases the amplitude of distension and alters the temporal relationship between distension and contraction waveforms. We describe the characteristics of esophageal distension during peristalsis and the relationship between distension and contraction in a relatively large cohort of normal subjects. These data can be used to compare differences between normal subjects and patients with various esophageal motility disorders in future studies.NEW & NOTEWORTHY We studied esophageal distension (surrogate of inhibition) ahead of contraction during peristalsis from intraluminal esophageal impedance measurements. Esophageal distension, similarly to contraction, travels the esophagus in a sequential manner, and the amplitude of esophageal distension increases from proximal to distal direction in the esophagus. Bolus volume, viscosity and posture have significant effects on the amplitude of distension and its temporal relationship with contraction.

Neuronal Control of Esophageal Peristalsis and Its Role in Esophageal Disease

PURPOSE OF REVIEW

Esophageal peristalsis is a highly sophisticated function that involves the coordinated contraction and relaxation of striated and smooth muscles in a cephalocaudal fashion, under the control of central and peripheral neuronal mechanisms and a number of neurotransmitters. Esophageal peristalsis is determined by the balance of the intrinsic excitatory cholinergic, inhibitory nitrergic and post-inhibitory rebound excitatory output to the esophageal musculature.

RECENT FINDINGS

Dissociation of the longitudinal and circular muscle contractions characterizes different major esophageal disorders and leads to esophageal symptoms. Provocative testing during esophageal high-resolution manometry is commonly employed to assess esophageal body peristaltic reserve and underpin clinical diagnosis. Herein, we summarize the main factors that determine esophageal peristalsis and examine their role in major and minor esophageal motility disorders and eosinophilic esophagitis.

Jackhammer esophagus with and without esophagogastric junction outflow obstruction demonstrates altered neural control resembling type 3 achalasia

BACKGROUND

Esophageal hypercontractility can manifest with and without esophagogastric junction (EGJ) outflow obstruction. We investigated clinical presentations and motility patterns in patients with esophageal hypercontractile disorders.

METHODS

Esophageal HRM studies fulfilling Chicago Classification 3.0 criteria for jackhammer esophagus (distal contractile integral, DCI >8000 mmHg.cm.s in ≥ 20% swallows) with (n = 30) and without (n = 83) EGJ obstruction (integrated relaxation pressure, IRP > 15 mm Hg) were retrospectively reviewed from five centers (4 in Europe, 1 in US). Single swallows (SS) and multiple rapid swallows (MRS) were analyzed using HRM software tools (IRP, DCI, distal latency, DL); MRS: SS DCI ratio >1 defined contraction reserve. Comparison groups were achalasia type 3 (n = 72, positive control for abnormal inhibition and EGJ obstruction) and healthy controls (n = 18). Symptoms, HRM metrics, and MRS contraction reserve were analyzed within jackhammer subgroups and comparison groups.

KEY RESULTS

The esophageal smooth muscle was excessively stimulated at baseline in jackhammer subgroups, with lack of augmentation following MRS identified more often compared with controls (P = .003) and type 3 achalasia (P = .07). Consistently abnormal inhibition was identified in type 3 achalasia (47%), and to a lower extent in jackhammer with obstruction (37%, P = .33), jackhammer esophagus (28%, P = .01), and controls (11%, P < .01 compared with type 3 achalasia). Perceptive symptoms (heartburn, chest pain) were common in jackhammer esophagus (P < .01 compared with type 3 achalasia), while transit symptoms (dysphagia) were more frequent with presence of EGJ obstruction (P ≤ .01 compared with jackhammer without obstruction).

CONCLUSIONS AND INFERENCES

The balance of excessive excitation and abnormal inhibition defines clinical and manometric manifestations in esophageal hypercontractile disorders.

Evaluation of Esophageal Contraction Reserve Using HRM in Symptomatic Esophageal Disease

Esophageal high resolution manometry (HRM) is the gold standard for assessment of esophageal motor disorders, but motor responses to the standard 5 mL water swallow protocol may not provide precision in defining minor motor disorders. Provocative maneuvers, particularly multiple rapid swallows (MRS), have been used to assess deglutitive inhibition during the repetitive swallows, and the contractile response following the final swallow of the sequence. The augmentation of esophageal smooth muscle contraction following MRS is termed contraction reserve. This is determined as the ratio between esophageal body contraction vigor (distal contractile integral, DCI) following MRS to the mean DCI after single swallows, which is ≥1 in the presence of contraction reserve. Reliable assessment of contraction reserve requires the performance of 3 MRS maneuvers during HRM. Absence of contraction reserve is associated with a higher likelihood of late postfundoplication dysphagia and may correlate with higher esophageal reflux burden on ambulatory reflux monitoring. Esophageal motor responses to abdominal compression, functional lumen imaging probe (FLIP) balloon distension, and pharmacologic testing (using edrophonium and cisapride) may correlate with contraction reserve. Other provocative tests useful during HRM include rapid drink challenge, solid and viscous swallows, and standardized test meals, which are more useful in evaluation of esophageal outflow obstruction and dysphagia syndromes than in identification of contraction reserve. Provocative maneuvers have been recommended as part of routine HRM protocols, and while useful clinical information can be gleaned from these maneuvers, further research is necessary to determine the precise role of provocative testing in clinical esophagology.

Topographical plots of esophageal distension and contraction: effects of posture on esophageal peristalsis and bolus transport

Each swallow induces a wave of inhibition followed by contraction in the esophagus. Unlike contraction, which can easily be measured in humans using high-resolution manometry (HRM), inhibition is difficult to measure. Luminal distension is a surrogate of the esophageal inhibition. The aim of this study was to determine the effect of posture on the temporal and quantitative relationship between distension and contraction along the entire length of the esophagus in normal healthy subjects by using concurrent HRM, HRM impedance (HRMZ), and intraluminal ultrasound (US). Studies were conducted in 15 normal healthy subjects in the supine and Trendelenburg positions. Both manual and automated methods were used to extract quantitative pressure and impedance-derived features from the HRMZ recordings. Topographical plots of distension and contraction were visualized along the entire length of the esophagus. Distension was also measured from the US images during 10-ml swallows at 5 cm above the lower esophageal sphincter. Each swallow was associated with luminal distension followed by contraction, both of which traversed the esophagus in a sequential/peristaltic fashion. Luminal distension (US) and esophageal contraction amplitude were greater in the Trendelenburg compared with the supine position. Length of esophageal breaks (in the transition zone) were reduced in the Trendelenburg position. Change in posture altered the temporal relationship between distension and contraction, and bolus traveled closer to the esophageal contraction in the Trendelenburg position. Topographical contraction-distension plots derived from HRMZ recordings is a novel way to visualize esophageal peristalsis. Future studies should investigate if abnormalities of esophageal distension are the cause of functional dysphagia. NEW & NOTEWORTHY Ascending contraction and descending inhibition are two important components of peristalsis. High-resolution manometry only measures the contraction phase of peristalsis. We measured esophageal distension from intraluminal impedance recordings and developed novel contraction-distension topographical plots to prove that similar to contraction, distension also travels in a peristaltic fashion. Change in posture from the supine to the Trendelenburg position also increased the amplitude of esophageal distension and contraction and altered the temporal relationship between distension and contraction.

Provocative testing in patients with jackhammer esophagus: evidence for altered neural control

Jackhammer esophagus (JE) is a hypercontractile disorder, the pathogenesis of which is incompletely understood. Multiple rapid swallows (MRS) and rapid drink challenge (RDC) are complementary tests used during high-resolution manometry (HRM) that evaluate inhibitory and excitatory neuromuscular function and latent obstruction, respectively. Our aim was to evaluate esophageal pathophysiology using MRS and RDC in 83 JE patients (28 men; median age: 63 yr; IQR: 54-70 yr). Twenty-one healthy subjects (11 men; median age: 28 yr; range: 26-30 yr) were used as a control group. All patients underwent solid-state HRM with ten 5-ml single swallows (SS) and one to three 10-ml MRS; 34 patients also underwent RDC. Data are shown as median (interquartile range). Abnormal motor inhibition was noted during at least one MRS test in 48% of JE patients compared with 29% of controls ( P = 0.29). Mean distal contractile integral (DCI) after MRS was significantly lower than after SS [6,028 (3,678-9,267) mmHg·cm·s vs. 7,514 (6,238-9,197) mmHg·cm·s, P = 0.02], as was highest DCI ( P < 0.0001). Consequently, 66% of JE patients had no contraction reserve. At least one variable of obstruction during RDC (performed in 34 patients) was outside the normal range in 25 (74%) of JE patients. Both highest DCI after SS and pressure gradient across the esophagogastric junction (EGJ) during RDC were higher in patients with dysphagia versus those without ( P = 0.04 and 0.01, respectively). Our data suggest altered neural control in JE patients with heterogeneity in inhibitory function. Furthermore, some patients had latent EGJ obstruction during RDC, which correlated with the presence of dysphagia. NEW & NOTEWORTHY Presence of abnormal inhibition was observed during multiple rapid swallows (MRS) in some but not all patients with jackhammer esophagus (JE). Unlike healthy subjects, JE patients were more strongly stimulated after single swallows than after MRS. An obstructive pattern was frequently observed during rapid drink challenge (RDC) and was related to presence of dysphagia. MRS and RDC during high-resolution manometry are useful to show individual pathophysiological patterns in JE and may guide optimal therapeutic strategies.

Genesis of Esophageal Pressurization and Bolus Flow Patterns in Patients With Achalasia Esophagus

BACKGROUND & AIMS

In patients with achalasia esophagus, swallows induce simultaneous pressure waves known as esophageal pressurization. We studied the mechanism of esophageal pressurization and bolus flow patterns in patients with type 2 or type 3 achalasia.

METHODS

We recorded high-resolution manometry with impedance and intraluminal ultrasound images concurrently in patients with type 2 achalasia (n = 6) or type 3 achalasia (n = 8) and in 10 healthy subjects (controls) during swallows of 5 mL of 0.5N saline. For each swallow, the ultrasound image was aligned with the pressure and impedance tracings to determine cavity and contact pressure, bolus arrival, bolus dwell time, and changes in muscle thickness at 5 cm and 10 cm above the lower esophageal sphincter.

RESULTS

In patients with type 2 achalasia, esophageal pressurization was associated with an increase in the muscle thickness and luminal narrowing but not complete luminal closure (ie, cavity pressure). Bolus arrival time in the distal esophagus after the onset of a swallow was delayed in patients with type 3 achalasia compared with control individuals because of early luminal closure. The early luminal closure was associated with a decrease in the muscle thickness. The bolus dwell time was shorter in patients with type 3 achalasia compared with control individuals. In patients with type 3 achalasia, the onset of simultaneous pressure wave was always a cavity pressure, but during contraction there were different periods of cavity and contact pressures in association with increases in muscle thickness that resulted in bolus segmentation.

CONCLUSIONS

We observed distinct mechanisms of esophageal pressurization and bolus flow patterns in patients with type 2 or type 3 achalasia esophagus compared with control individuals. These findings will increase our understanding of the mechanisms of dysphagia.

Comparison of motor diagnoses by Chicago Classification versions 2.0 and 3.0 on esophageal high-resolution manometry

BACKGROUND

The Chicago Classification (CC) uses high-resolution manometry (HRM) software tools to designate esophageal motor diagnoses. We evaluated changes in diagnostic designations between two CC versions, and determined motor patterns not identified by either version.

METHODS

In this observational cohort study of consecutive patients undergoing esophageal HRM over a 6-year period, proportions meeting CC 2.0 and 3.0 criteria were segregated into esophageal outflow obstruction, hypermotility, and hypomotility disorders. Contraction wave abnormalities (CWA), and 'normal' cohorts were recorded. Symptom burden was characterized using dominant symptom intensity and global symptom severity. Motor diagnoses, presenting symptoms, and symptom burden were compared between CC 2.0 and 3.0, and in cohorts not meeting CC diagnoses.

KEY RESULTS

Of 2569 eligible studies, 49.9% met CC 2.0 criteria, but only 40.3% met CC 3.0 criteria (P<.0001). Between CC 2.0 and 3.0, 82.8% of diagnoses were concordant. Discordance resulted from decreasing proportions of hypermotility (4.4%) and hypomotility (9.0%) disorders, and increase in 'normal' designations (13.0%); esophageal outflow obstruction showed the least variation between CC versions. Symptom burden was higher with CC 3.0 diagnoses (P≤.005) but not with CC 2.0 diagnoses (P≥.1). Within 'normal' cohorts for both CC versions, CWA were associated with higher likelihood of esophageal symptoms, especially dysphagia, regurgitation, and heartburn, compared to truly normal studies (P≤.02 for each comparison).

CONCLUSIONS AND INFERENCES

Despite lower sensitivity, CC 3.0 identifies esophageal motor disorders with higher symptom burden compared to CC 2.0. CWA, which are associated with both transit and perceptive symptoms, are not well identified by either version.

Regulation and dysregulation of esophageal peristalsis by the integrated function of circular and longitudinal muscle layers in health and disease

Muscularis propria throughout the entire gastrointestinal tract including the esophagus is comprised of circular and longitudinal muscle layers. Based on the studies conducted in the colon and the small intestine, for more than a century, it has been debated whether the two muscle layers contract synchronously or reciprocally during the ascending contraction and descending relaxation of the peristaltic reflex. Recent studies in the esophagus and colon prove that the two muscle layers indeed contract and relax together in almost perfect synchrony during ascending contraction and descending relaxation of the peristaltic reflex, respectively. Studies in patients with various types of esophageal motor disorders reveal temporal disassociation between the circular and longitudinal muscle layers. We suggest that the discoordination between the two muscle layers plays a role in the genesis of esophageal symptoms, i.e., dysphagia and esophageal pain. Certain pathologies may selectively target one and not the other muscle layer, e.g., in eosinophilic esophagitis there is a selective dysfunction of the longitudinal muscle layer. In achalasia esophagus, swallows are accompanied by the strong contraction of the longitudinal muscle without circular muscle contraction. The possibility that the discoordination between two muscle layers plays a role in the genesis of esophageal symptoms, i.e., dysphagia and esophageal pain are discussed. The purpose of this review is to summarize the regulation and dysregulation of peristalsis by the coordinated and discoordinated function of circular and longitudinal muscle layers in health and diseased states.

Distal esophageal spasm and the Chicago classification: is timing everything?

BACKGROUND

According to the Chicago classification of esophageal motility disorders, distal esophageal spasm (DES) is defined as premature esophageal contractions (distal latency [DL] <4.5 s) for ≥20% of swallows, in the presence of a normal mean integral relaxation pressure (IRP). However, some patients with symptoms of DES have rapid contractions with a normal DL. The aim of this study was to characterize these patients and compare their clinical characteristics to those of patients classified as DES.

METHODS

We retrospectively compared clinical characteristics and high-resolution manometry findings of patients with rapid contractions with normal latency to those meeting the Chicago classification criteria for DES.

KEY RESULTS

Over a 3-year period, nine patients were diagnosed with DES and 14 showed rapid contractions in the distal esophagus with normal latency. The latter were younger than DES patients (60 ± 4 vs 72 ± 3 years, p < 0.05). Dysphagia and retrosternal pain occurred to a similar degree in both groups. Weight loss and abnormal barium esophagogram tended to be more frequent in DES patients. There was no difference in contractile front velocity (CFV) and in distal contractile integral (DCI) between patients with DES and rapid contractions with normal latency. Lower esophageal sphincter pressures were not different between groups. However, IRP was significantly higher in DES compared to rapid contractions with normal latency (11.7 ± 0.6 mmHg vs 7.6 ± 1.2 mmHg, p < 0.05), albeit still within the normal range.

CONCLUSIONS & INFERENCES

These data suggest that patients with simultaneous contractions with normal latency represent a group of patients with many features similar to DES.

Radiofrequency Catheter Ablation for Atrial Fibrillation Elicited "Jackhammer Esophagus": A New Complication Due to Vagal Nerve Stimulation?

Radiofrequency catheter ablation (RFCA) is a potentially curative method for treatment of highly symptomatic and drug-refractory atrial fibrillation (AF). However, this technique can provoke esophageal and nerve lesion, due to thermal injury. To our knowledge, there have been no reported cases of a newly described motor disorder, the Jackhammer esophagus (JE) after RFCA, independently of GERD. We report a case of JE diagnosed by high-resolution manometry (HRM), in whom esophageal symptoms developed 2 weeks after RFCA, in absence of objective evidence of GERD. A 65-year-old male with highly symptomatic, drug-refractory paroxysmal AF was candidate to complete electrical pulmonary vein isolation with RFCA. Prior the procedure, the patient underwent HRM and impedance-pH to rule out GERD or hiatal hernia presence. All HRM parameters, according to Chicago classification, were within normal limits. No significant gastroesophageal reflux was documented at impedance pH monitoring. Patient underwent RFCA with electrical disconnection of pulmonary vein. After two weeks, patient started to complain of dysphagia for solids, with acute chest-pain. The patient repeated HRM and impedance-pH monitoring 8 weeks after RFCA. HRM showed in all liquid swallows the typical spastic hypercontractile contractions consistent with the diagnosis of JE, whereas impedance-pH monitoring resulted again negative for GERD. Esophageal dysmotility can represent a possible complication of RFCA for AF, probably due to a vagal nerve injury, and dysphagia appearance after this procedure must be timely investigated by HRM.

Effects of remifentanil on esophageal motility: a double-blind, randomized, cross-over study in healthy volunteers

BACKGROUND

Recent studies have shown that remifentanil increases the risk of aspiration and induces subjective swallowing difficulties. The mechanisms are not completely understood. Here, we investigated whether remifentanil impairs esophageal motility and hypothesized that this is one possible underlying mechanism. Naloxone was used to evaluate whether the effects of remifentanil are mediated through opioid receptors. We also examined subjective swallowing difficulties and the influence of metoclopramide on remifentanil-induced effects.

METHODS

Fourteen healthy volunteers participated in a double-blind, randomized, cross-over trial at the University Hospital in Örebro, Sweden. They were studied on two different occasions, during which they were randomly assigned to receive either naloxone given as a bolus of 6 μg/kg followed by an infusion of 0.1 μg/kg/min, or saline 5 min before target-controlled infusions of remifentanil at three target-site concentrations: 1, 2, and 3 ng/ml. On both occasions, 0.2 mg/kg metoclopramide was given before the final measurement. Five swallows were performed during each measuring condition, and the metrics defining esophageal motility were measured by high-resolution manometry. Outcomes were differences in the metrics at baseline vs. during remifentanil infusion, with naloxone vs. placebo, and with remifentanil before and after metoclopramide administration. Differences in swallowing difficulties were also recorded.

RESULTS

Remifentanil decreased swallow-evoked esophagogastric junction relaxation and the latency time of esophageal peristalsis. There were no significant effects of naloxone or metoclopramide on remifentanil-induced effects, and we detected no differences in swallowing difficulties.

CONCLUSIONS

Remifentanil induces dysfunction of esophageal motility; this may contribute to the elevated risk of regurgitation and aspiration.

Measurement of peak esophageal luminal cross-sectional area utilizing nadir intraluminal impedance

BACKGROUND

Multichannel intraluminal impedance (MII) is currently used to monitor gastroesophageal reflux and esophageal bolus clearance. We describe a novel methodology to measure maximal luminal cross-sectional area (CSA) during bolus transport from MII measurements.

METHODS

Studies were conducted in-vitro (test tubes) and in-vivo (healthy subjects). Concurrent MII, high resolution manometry, and intraluminal ultrasound (US) images were recorded 7-cm above the lower esophageal sphincter. Swallows with two concentrations of saline, 0.1 and 0.5 N, of bolus volumes 5, 10, and 15 cc were performed. The CSA was estimated by solving two algebraic Ohm's law equations, resulting from the two saline solutions. The CSA calculated from impedance method was compared with the CSA measured from the intraluminal US images.

KEY RESULTS

The CSA measured in duplicate from B-mode US images showed a mean difference between the two manual delineations to be near zero, and the repeatability coefficient was within 7.7% of the mean of the two CSA measurements. The calculated CSA from the impedance measurements strongly correlated with the US measured CSA (R(2) ≅ 0.98). A detailed statistical analysis of the impedance and US measured CSA data indicated that the 95% limits of agreement between the two methods ranged from -9.1 to 13 mm(2) . The root mean square error of the two measurements was 4.8% of the mean US-measured CSA.

CONCLUSIONS & INFERENCES

We describe a novel methodology to measure peak esophageal luminal CSA from the nadir impedance during peristalsis. Further studies are needed to determine if it is possible to measure patterns of luminal distension during peristalsis across the entire length of the esophagus from the MII recordings.

Esophageal distension during bolus transport: can it be detected by intraluminal impedance recordings?

BACKGROUND

Esophageal multiple intraluminal impedance (MII) measurement has been used to detect gastro-esophageal reflux and bolus transport. It is not clear if MII can detect changes in luminal cross sectional area (CSA) during bolus transport. Intraluminal ultrasound (US) images, MII, and high resolution manometry (HRM) were recorded simultaneously to determine temporal relationship between CSA and impedance during esophageal bolus transport and to define the relationship between peak distension and nadir impedance.

METHODS

Studies were conducted in five healthy subjects. MII, HRM, and US images were recorded 6 cm above LES. Esophageal distensions were studied during swallows and injections of 0.5 N saline bolus into the esophagus.

KEY RESULTS

Temporal change in esophageal CSA correlates with changes in impedance (r-value: mean ± SD = -0.80 ± 0.08, range: -0.94 to -0.66). Drop in impedance during distension occurs as a two-step process; initial large drop associated with onset of CSA increase, followed by a small drop during which majority of the CSA increase occurs. Peak CSA and nadir impedance occur within 1 s of each other. Increase in swallow and injection volumes increased the CSA, had no effect on large drop but increased the small drop amplitude. We observed a significant correlation between peak CSA and nadir impedance (r = -0.90, p < 0.001) and a better correlation between peak CSA and inverse impedance (r = 0.94, p < 0.001).

CONCLUSIONS & INFERENCES

Further studies are needed to confirm that intraluminal impedance recordings may be used to measure luminal CSA during esophageal bolus transport.

Reproducibility patterns of multiple rapid swallows during high resolution esophageal manometry provide insights into esophageal pathophysiology

BACKGROUND

Multiple rapid swallows (MRS) during esophageal high resolution manometry (HRM) assess esophageal neuromuscular integrity by evaluating postdeglutitive inhibition and rebound contraction, but most reports performed only a single MRS sequence. We assessed patterns of MRS reproducibility during clinical HRM in comparison to a normal cohort.

METHODS

Consecutive clinical HRM studies were included if two separate MRS sequences (four to six rapid swallows ≤4 s apart) were successfully performed. Chicago Classification diagnoses were identified; contraction wave abnormalities were additionally recorded. MRS-induced inhibition (contraction ≤3 cm during inhibition phase) and rebound contraction was assessed, and findings compared to 18 controls (28.0 ± 0.7 year, 50.0% female). Reproducibility consisted of similar inhibition and contraction responses with both sequences; discordance was segregated into inhibition and contraction phases.

KEY RESULTS

Multiple rapid swallows were successfully performed in 89.3% patients and all controls; 225 subjects (56.2 ± 0.9 year, 62.7% female) met study inclusion criteria. Multiple rapid swallows were reproducible in 76.9% patients and 94.4% controls (inhibition phase: 88.0% vs 94.4%, contraction phase 86.7% vs 100%, respectively, p = ns). A gradient of reproducibility was noted, highest in well-developed motor disorders (achalasia spectrum, hypermotility disorders, and aperistalsis, 91.7-100%, p = ns compared to controls); and lower in lesser motor disorders (contraction wave abnormalities, esophageal body hypomotility) or normal studies (62.2-70.8%, p < 0.0001 compared to well-developed motor disorders). Inhibition phase was most discordant in contraction wave abnormalities, while contraction phase was most discordant when studies were designated normal.

CONCLUSIONS & INFERENCES

Multiple rapid swallows are highly reproducible, especially in well-developed motor disorders, and complement the standard wet swallow manometry protocol.

Lung transplantation triggered "jackhammer esophagus": a case report and review of literature

A 19-years-old girl was referred for lung transplant due to end stage lung disease secondary to idiopathic bilateral bronchiectasis. Her routine pre lung transplant evaluation showed normal esophageal high-resolution manometry (HRM) and 24-hours impedance pH monitoring. Four weeks after the bilateral sequential lung transplantation (LTx), she developed dysphagia, chest pain and regurgitation, complicated by aspiration pneumonia. Repeated HRM showed Jackhammer esophagus, delayed gastric emptying and abnormal 24-hour pH impedance monitoring consistent with the diagnosis of gastroesophageal reflux disease. Twelve weeks after LTx, she was symptom free, HRM and 24-hour impedance pH monitoring returned to normal. To the best of our knowledge, this rare transient esophageal hypercontractility episode occurred after LTx and recovered without any specific treatment was never reported in literature. The etiopathogenesis of Jackhammer esophagus in general and LTx induced dysmotility in particular is discussed and reviewed.

Reinterpretation of follow-up, high-resolution manometry for esophageal motility disorders based on the updated chicago classification

The aim of this study was to assess changes between primary classification of esophageal motility disease and follow-up classification by high resolution manometry (HRM) and to determine whether previously classified diseases could be recategorized according to the updated Chicago Classification published in 2011. We reviewed individual medical records and HRM findings twice for each of 13 subjects. We analyzed primary and follow-up HRM findings based on the original Chicago Classification. We then reclassified the same HRM findings according to the updated Chicago Classification. This case series revealed the variable course of esophageal motility disorders; some patients experienced improvement, whereas others experienced worsening symptoms. Four cases were reclassified from variant achalasia to peristaltic abnormality, one case from diffuse esophageal spasm to type II achalasia and one case from peristaltic abnormality to variant achalasia. Four unclassified findings were recategorized as variant achalasia. In conclusion, esophageal motility disorders are variable and may not be best conceptualized as an independent group. Original classifications can be recategorized according to the updated Chicago Classification system. More research is needed on this topic.

Symptomatic diffuse esophageal spasm as a major ictal manifestation of post-traumatic epilepsy: a case report

Post-traumatic epilepsy (PTE) can create diagnostic confusion when typical epileptic seizures are not manifest. Abdominal symptoms as a manifestation of PTE are rare in this setting. We present a 43-year-old female with paroxysmal chest and abdominal pain, nausea, salivation, and intermittent dysphagia. Esophageal testing demonstrated diffuse esophageal spasm, but smooth muscle relaxants provided no relief. Finally, after history revealed that a motor vehicle accident temporally preceded symptom onset, video electroencephalography confirmed PTE. Therapy with anti-epileptic drug completely resolved symptoms, and the esophageal motor pattern normalized. We speculate that abnormal epileptiform discharges from the seizure focus altered cerebral input to intrinsic esophageal innervation, resulting in inhibitory dysfunction and a picture resembling diffuse esophageal spasm. This is the first report of symptomatic esophageal spasm as a major ictal manifestation of PTE.

Evaluation of esophageal motor function in clinical practice

Esophageal motor function is highly coordinated between central and enteric nervous systems and the esophageal musculature, which consists of proximal skeletal and distal smooth muscle in three functional regions, the upper and lower esophageal sphincters, and the esophageal body. While upper endoscopy is useful in evaluating for structural disorders of the esophagus, barium esophagography, radionuclide transit studies, and esophageal intraluminal impedance evaluate esophageal transit and partially assess motor function. However, esophageal manometry is the test of choice for the evaluation of esophageal motor function. In recent years, high-resolution manometry (HRM) has streamlined the process of acquisition and display of esophageal pressure data, while uncovering hitherto unrecognized esophageal physiologic mechanisms and pathophysiologic patterns. New algorithms have been devised for analysis and reporting of esophageal pressure topography from HRM. The clinical value of HRM extends to the pediatric population, and complements preoperative evaluation prior to foregut surgery. Provocative maneuvers during HRM may add to the assessment of esophageal motor function. The addition of impedance to HRM provides bolus transit data, but impact on clinical management remains unclear. Emerging techniques such as 3-D HRM and impedance planimetry show promise in the assessment of esophageal sphincter function and esophageal biomechanics.

The importance of interstitial cells of cajal in the gastrointestinal tract

Gastrointestinal (GI) motility function and its regulation is a complex process involving collaboration and communication of multiple cell types such as enteric neurons, interstitial cells of Cajal (ICC), and smooth muscle cells. Recent advances in GI research made a better understanding of ICC function and their role in the GI tract, and studies based on different types of techniques have shown that ICC, as an integral part of the GI neuromuscular apparatus, transduce inputs from enteric motor neurons, generate intrinsic electrical rhythmicity in phasic smooth muscles, and have a mechanical sensation ability. Absence or improper function of these cells has been linked to some GI tract disorders. This paper provides a general overview of ICC; their discovery, subtypes, function, locations in the GI tract, and some disorders associated with their loss or disease, and highlights some controversial issues with regard to the importance of ICC in the GI tract.

Multiple rapid swallow responses segregate achalasia subtypes on high-resolution manometry

BACKGROUND

Multiple rapid swallows (MRS) inhibit esophageal peristalsis and lower esophageal sphincter (LES) tone; a rebound excitatory response then results in an exaggerated peristaltic sequence. Multiple rapid swallows responses are dependent on intact inhibitory and excitatory neural function and could vary by subtype in achalasia spectrum disorders.

METHODS

Consecutive subjects with incomplete LES relaxation on high-resolution manometry (HRM) (Sierra Scientific, Los Angeles, CA, USA) in the absence of mechanical obstruction were prospectively identified. Achalasia spectrum disorders were classified and HRM plots reviewed according to Chicago criteria. Esophageal peristaltic performance and LES function were assessed after 10 wet swallows and MRS (five 2 mL water swallows 2-3 s apart). Findings were compared with 18 healthy controls (28.5 ± 0.6 years, 44% women).

KEY RESULTS

A total of 46 subjects (57.1 ± 2.1 years, 52.2% women) met inclusion criteria. There was complete failure of peristalsis with MRS in all subjects with achalasia subtypes 1 and 2. In contrast, 80% of achalasia subtype 3 and incomplete LES relaxation (EGJ outflow obstruction) with preserved esophageal body peristalsis had a contractile response to MRS (P < 0.001 compared with subtypes 1 and 2); controls demonstrated 94.4% peristalsis. Percent decrease in LES residual pressure during MRS (compared to wet swallows) segregated achalasia subtypes; those with aperistalsis (subtypes 1 and 2) had a lesser decline (22.6%) compared to those with retained esophageal body peristalsis (40.5%) and controls (51.3%, P < 0.001 across groups).

CONCLUSIONS & INFERENCES

Multiple rapid swallow responses segregate achalasia spectrum disorders into two patterns differentiated by presence or absence of esophageal body contraction response to wet swallows. These findings support subtyping of achalasia, with pathophysiologic implications.

The value of multiple rapid swallows during preoperative esophageal manometry before laparoscopic antireflux surgery

BACKGROUND

When multiple swallows are rapidly administered, esophageal peristalsis is inhibited, and pronounced lower esophageal sphincter relaxation ensues. After the last swallow of the series, a robust contraction sequence results. The authors hypothesize that multiple rapid swallows (MRS) may have value in predicting esophageal transit symptoms in patients undergoing laparoscopic antireflux surgery (LARS).

METHODS

Records of patients undergoing esophageal high-resolution manometry (HRM) before LARS were evaluated. The evaluation of MRS included adequate inhibitory response during swallows and the contraction pattern after MRS. Dysphagia was scored based on a product of symptom frequency and severity using 5-point Likert scales. A composite dysphagia score comprised the sum of scores for solid and liquid dysphagia, and a score of 4 or higher was considered clinically significant. The normal and abnormal MRS responses of patients with preoperative, early, and late postoperative dysphagia were compared with those of patients with no dysphagia.

RESULTS

In this study, 63 patients (mean age, 60.3 ± 1.7 years, 48 women) undergoing HRM before LARS successfully performed MRS (median, 5 swallows; longest interval between swallows, 3.2 ± 0.1 s). After MRS, 14 patients (22.2%) had an intact peristaltic sequence. Complete failure of peristalsis was seen in 21 (33.3%), and incomplete esophageal inhibition in 25 (39.7%) of the remaining patients. When stratified by presence or absence of dysphagia, 58.3% of the subjects without dysphagia had a normal MRS response, whereas 83.3% had formation of peristaltic segments after MRS. In contrast, only 14% of the subjects with dysphagia had a normal MRS response (p ≤ 0.003 vs. the subjects with no dysphagia). Abnormal MRS responses were more prevalent in the patients with any preoperative and late postoperative dysphagia (p = 0.04 across groups) and in those with clinically significant dysphagia (p = 0.08 across groups).

CONCLUSIONS

High-resolution manometry with MRS helps to predict dysphagia in subjects undergoing preoperative esophageal function testing before LARS.

Evaluation of esophageal contractile propagation using esophageal pressure topography

BACKGROUND

High-resolution manometry and esophageal pressure topography have enhanced our ability to analyze esophageal motor disturbances by improving the detail and accuracy of measurements of peristaltic activity.This has been extremely helpful in the evaluation of disorders of rapid propagation as the technique is able to define important time points and physiologic landmarks that are crucial in defining peristaltic velocity and latency intervals.

PURPOSE

The goal of the current review will be to assess how esophageal pressure topography has impacted our ability to define important phenotypes of rapid propagation. Additionally, this review will also be utilized to complement the description of the Chicago Classification of Esophageal Motor Disorders, which is presented in this supplement issue.

A novel pattern of longitudinal muscle contraction with subthreshold pharyngeal stimulus: a possible mechanism of lower esophageal sphincter relaxation

A subthreshold pharyngeal stimulus induces lower esophageal sphincter (LES) relaxation and inhibits progression of ongoing peristaltic contraction in the esophagus. Recent studies show that longitudinal muscle contraction of the esophagus may play a role in LES relaxation. Our goal was to determine whether a subthreshold pharyngeal stimulus induces contraction of the longitudinal muscle of the esophagus and to determine the nature of this contraction. Studies were conducted in 16 healthy subjects. High resolution manometry (HRM) recorded pressures, and high frequency intraluminal ultrasound (HFIUS) images recorded longitudinal muscle contraction at various locations in the esophagus. Subthreshold pharyngeal stimulation was induced by injection of minute amounts of water in the pharynx. A subthreshold pharyngeal stimulus induced strong contraction and caudal descent of the upper esophageal sphincter (UES) along with relaxation of the LES. HFIUS identified longitudinal muscle contraction of the proximal (3-5 cm below the UES) but not the distal esophagus. Pharyngeal stimulus, following a dry swallow, blocked the progression of dry swallow-induced peristalsis; this was also associated with UES contraction and descent along with the contraction of longitudinal muscle of the proximal esophagus. We identify a unique pattern of longitudinal muscle contraction of the proximal esophagus in response to subthreshold pharyngeal stimulus, which we propose may be responsible for relaxation of the distal esophagus and LES through the stretch sensitive activation of myenteric inhibitory motor neurons.

Deglutitive inhibition, latency between swallow and esophageal contractions and primary esophageal motor disorders

Swallowing induces an inhibitory wave that is followed by a contractile wave along the esophageal body. Deglutitive inhibition in the skeletal muscle of the esophagus is controlled in the brain stem whilst in the smooth muscle, an intrinsic peripheral control mechanism is critical. The latency between swallow and contractions is determined by the pattern of activation of the inhibitory and excitatory vagal pathways, the regional gradients of inhibitory and excitatory myenteric nerves, and the intrinsic properties of the smooth muscle. A wave of inhibition precedes a swallow-induced peristaltic contraction in the smooth muscle part of the human oesophagus involving both circular and longitudinal muscles in a peristaltic fashion. Deglutitive inhibition is necessary for drinking liquids which requires multiple rapid swallows (MRS). During MRS the esophageal body remains inhibited until the last of the series of swallows and then a peristaltic contraction wave follows. A normal response to MRS requires indemnity of both inhibitory and excitatory mechanisms and esophageal muscle. MRS has recently been used to assess deglutitive inhibition in patients with esophageal motor disorders. Examples with impairment of deglutitive inhibition are achalasia of the LES and diffuse esophageal spasm.

Swallow induces a peristaltic wave of distension that marches in front of the peristaltic wave of contraction

BACKGROUND

Current understanding is that swallow induces simultaneous inhibition of the entire esophagus followed by a sequential wave of contraction (peristalsis). We observed a pattern of luminal distension preceding contraction which suggested that inhibition may also traverses in a peristaltic fashion. Our aim is to determine the relationship between contraction and luminal distension during bolus transport.

METHODS

Eight subjects using two solid-state pressure and two ultrasound (US) transducers were studied. Synchronous pressure and US images were obtained with wet swallows and after edrophonium and atropine. Luminal cross-sectional area (CSA) at 2 cm and 12 cm above the lower esophageal sphincter (LES) were recorded. Relationship between pressure and CSA at each site, propagation velocity of peak pressure and peak distension waves were determined. Fluoroscopy coupled with manometry was also performed in five normal subjects.

KEY RESULTS

Esophageal distension precedes contraction wave at both-recorded sites. During distension, esophageal pressure remains constant while luminal CSA increases significantly. The onset and the peak of distension wave traverses in a peristaltic fashion between both sites. A tight coupling exists between the peak distension and peak contraction waves with similar velocities (3.7 cm s(-1) and 3.6 cm s(-1)) of propagation. The degree of distension is greater at 2 cm compared to 12 cm. Atropine and edrophonium reduced and increased the contraction pressure respectively, without affecting the distension wave. Fluoroscopic study confirmed that the wave of distension traverses the esophagus in a peristaltic fashion.

CONCLUSIONS & INFERENCES

Distension and contraction waves are tightly coupled to each other and both traverse in a peristaltic fashion.

Distal contraction latency: a measure of propagation velocity optimized for esophageal pressure topography studies

OBJECTIVES

A defining feature of peristalsis is propagation velocity, which determines the timing of the distal contraction relative to the swallow. This study aimed to exploit a coordinate-based strategy to quantify the normal latency of the distal esophageal contraction as a measure of propagation velocity optimized for high-resolution esophageal pressure topography (EPT) studies.

METHODS

EPT studies for 75 healthy volunteers were merged in a computer simulation. Swallows were synchronized and analyzed as a 100 × 200 pixel grid that normalized esophageal length from the pharynx to the stomach for a 20-s period to first calculate a composite for each individual and then to establish normative values for the morphology and latency of the distal contraction among individuals.

RESULTS

Stereotyped landmarks in composite EPT studies were pressure troughs in the proximal and distal esophagus isolating the distal segment and the contractile deceleration point (CDP) localizing the termination of peristalsis in the distal segment. Distal contractile latency was timed to the CDP (median 6.0 s, 95% confidence interval 4.8-7.6 s) and to lower esophageal sphincter (LES) contraction (median 9.2 s, 95% confidence interval 6.5-11.5 s). Illustrative examples are shown of rapidly conducted contractions with normal or short latency, suggesting short latency to be the preferable EPT metric of rapid propagation.

CONCLUSIONS

The proposed scheme, utilizing the topographic coordinates of contraction relative to the swallow as an alternative to conventional measures of peristaltic velocity, lays the foundation for a physiologically grounded classification of peristaltic abnormalities in EPT. Future studies will test the clinical utility of this scheme.

Botulinum toxin injection in dysphagia syndromes with preserved esophageal peristalsis and incomplete lower esophageal sphincter relaxation

BACKGROUND

Botulinum toxin injection into the lower esophageal sphincter (LES) treats dysphagia syndromes with preserved peristalsis and incomplete LES relaxation (LESR). We evaluated clinical and esophageal motor characteristics predicting response, and compared duration of efficacy to similarly treated achalasia patients.

METHODS

Thirty-six subjects (59 ± 2.2 years, 19F/17M) with incomplete LESR on high resolution manometry (HRM) treated with botulinum toxin injection were identified. Individual and composite symptom indices were calculated, and HRM characteristics extracted. Symptom resolution for 6 months was a primary outcome measure, and repeat botulinum toxin injection, dysphagia recurrence or employment of alternate therapeutic approaches were secondary outcome measures. Duration of response was compared using Kaplan-Meier survival curves to a historical cohort of similarly treated achalasia subjects.

KEY RESULTS

Response lasted a mean of 12.8 ± 2.3 months. Symptom relief for >6 months was seen in 58.3%; short (<6 months) response was associated with younger age, higher chest pain index, and esophageal body spastic features (P ≤ 0.04). On multivariate logistic regression, chest pain, younger age and contraction amplitudes >180 mmHg independently predicted <6 months relief (P < 0.05 for each). On survival analysis, relief with a single injection extended to 1 year in 54.8% and 1.5 years in 49.8%, statistically equivalent to that reported by 42 similarly treated achalasia subjects (59 ± 3.2 years, 24F/18M). Symptom relief was more prolonged compared to achalasia when repeat injections were performed on demand (P = 0.003).

CONCLUSIONS & INFERENCES

Botulinum toxin injections can provide lasting symptom relief in dysphagia syndromes with incomplete LESR. Prominent perceptive symptoms and non-specific spastic features may predict shorter relief.

Physiology of diffuse esophageal spasm (DES)--when normal swallows are not normal

BACKGROUND

 Diffuse esophageal spasm (DES) is characterized on manometry by a combination of simultaneous contractions and normal swallows. The aim of this study was to examine the manometric characteristics of simultaneous and 'normal' swallows in patients with DES patients compared with normal controls.

METHODS

Manometric studies from 69 patients with DES and 20 controls were analysed to determine the proportion of normal, hypertensive, ineffective and simultaneous contractions, and the velocity of propagation along the esophagus, the duration and amplitude of contraction and the relaxation characteristics (nadir and duration) of the lower esophageal sphincter.

KEY RESULTS

 The propagation velocity was the only significant difference between normal swallows and simultaneous contractions in DES patients (middle third: 49.2 VS 101.2 mm s(-1), P ≤ 0.001 lower third: 44.1 VS 88.7 mm s(-1), P ≤ 0.001). 'Normal' swallows in patients with DES had a greater velocity of propagation than those in age-matched control subjects (middle third: 49.2 VS 37.0 mm s(-1), P = 0.02, lower third: 44.1 VS 23.3 mm s(-1), P ≤ 0.001).

CONCLUSIONS & INFERENCES

 As expected, simultaneous contractions of DES patients differ from 'normal' swallows in DES patients mainly regarding the velocity of propagation of contraction but are similar in amplitude, however 'normal' swallows of DES patients are also more rapidly propagated along the esophagus than normal swallows of a control group suggesting that all swallows in DES are affected to some degree by the same process.

Basal and residual lower esophageal pressures increase in old age in classic achalasia, but not vigorous achalasia

BACKGROUND AND AIM

The relationship between age and esophageal motility parameters (i.e. basal and residual pressure of the lower esophageal sphincter [LES]) remains to be established in achalasia patients, possibly because most previous studies did not distinguish between classic and vigorous achalasia patients. We investigated the relationship between age and esophageal motility parameters in both classic and vigorous achalasia patients.

METHODS

A retrospective review of esophageal manometry data in a single center was undertaken. Basal and residual pressure for LES was analyzed. A total of 103 achalasia patients were enrolled, comprising 84 classic and 19 vigorous types. They were subdivided into three different age groups as follows: 21-40 years old (group A), 41-60 years old (group B), and over 60 years old (group C).

RESULTS

In classic achalasia patients (M : F = 27:57, mean age = 44 +/- 15 years old) the older age group showed a significantly higher basal LES pressure (49.62 +/- 19.63 mmHg) than the younger age group (P < 0.0001). Moreover, the older age group also showed significantly high residual LES pressure (20.46 +/- 8.61 mmHg) than the younger age group (P = 0.0006). In contrast, in vigorous achalasia patients (M : F = 12:7, mean age: 47 +/- 15 years old) there were no difference between age and motility indices (all P > 0.05).

CONCLUSION

In classic achalasia patients there appears to be a correlation between age and esophageal motility indices, especially basal and residual LES pressure. Such correlations do not appear to exist for vigorous achalasia patients.

Multiple rapid swallowing: a complementary test during standard oesophageal manometry

Multiple rapid swallowing (MRS) stimulates neural inhibition resulting in abolition of contractions in the oesophageal body (OB) and complete lower oesophageal sphincter (LOS) relaxation which is followed by peristalsis and LOS contraction. The aim of this study was to evaluate the yield of MRS to detect abnormalities in inhibitory or excitatory oesophageal mechanisms in patients with oesophageal symptoms and either normal standard manometry or ineffective oesophageal motility (IOM). MRS (five water swallows, 2 mL, separated by 2-3 s) was evaluated in 23 healthy subjects, 109 symptomatic patients with normal standard sleeve manometry and in 48 patients with IOM. Healthy subjects had complete inhibition of OB motility during MRS and a strong motor response after MRS, i.e. amplitude of OB contractions in the oesophageal body and LOS tone being higher than after single swallows. Almost 70% of patients with oesophageal symptoms and normal manometry had abnormal MRS, mainly consistent on inability to increase amplitude of OB contractions after MRS. Nearly, half of the patients with IOM were able to normalize OB contractions after MRS. MRS is a simple complementary test that can be added to standard oesophageal manometry. Two-thirds of patients with normal manometry show abnormal MRS that could potentially underlie their symptoms. A normal response to MRS in patients with severe IOM might be used to predict response to prokinetic treatment.

Interstitial cells of Cajal in the gut - A gastroenterologist’s point of view

Alterations of normal function of interstitial cells of Cajal (ICC) are reported in many intestinal disorders. Diagnosis of their involvement is rare (infrequent), but necessary to propose a specific treatment. This article reviews the place of ICC in the pathogenesis of achalasia, gastroesophageal reflux disease, infantile hypertrophic pyloric stenosis, chronic intestinal pseudo-obstruction and slow transit constipation. Moreover we discuss the role of the Cajal cells in the development of stromal tumors of the gastrointestinal tract.