Prevalence and Impact of Gastrointestinal Manifestations in COVID-19 Patients: A Systematic Review.

Background and objective: The aim of this study is to systematically analyze and summarize the implications of COVID-19 on the digestive system by quantitatively evaluating the prevalence of gastrointestinal symptoms such as nausea, vomiting, abdominal pain, constipation, diarrhea, anorexia. reported in COVID-19 cases. We simultaneously investigated other variables to determine the association of such symptoms in COVID-19 patients which can potentially influence the disease prognosis and outcome. This systematic review presents an updated literature on the issue as it requires more scientific discussion in order to better inform the medical community and authorities so that appropriate measures can be taken to control the virus outbreak. Methods: MEDLINE database was searched to identify relevant articles. Data was analyzed and synthesized from the 16 eligible studies which exclusively reported GI symptoms in COVID-19 patients along with the disease prognosis. A meta-analysis of studies having adequate information regarding the prevalence of specific GI symptoms in association with other relevant independent variables was performed. Results: From the search strategy, we identified 16 articles which fit our eligibility criteria comprising of 10 cross-sectional studies, 2 cohort study, 1 RCT and 3 observational studies. From these pooled studies, 6 articles exclusively talked about COVID-19 patients in which GI symptoms were reported and adequately discussed. In a total of 3646 patients, GI symptoms were documented in (16.2%-10.1%) patients. The most prevalent GI symptom was diarrhea (47%) but the most common clinical manifestation reported was fever (77.4%). Among the adult patients, hypertension (11.6%) was the most frequently reported comorbidity. Presence of viral RNA in stool sample was noted in 16.7% patients with GI symptom. In patients who complained of having GI symptoms, an abnormal liver function was largely observed, with an elevated ALT level in (10.9%) and an elevated AST in (8.8%) of the patients. Evidence of vertical transmission (14.2%) was reported in one study which highlights the extent and mode of viral transmission. It was observed that a great majority of the patients in the 6 studies reporting specifically on patients with GI symptoms were on antiviral therapy (68.6%) as the standard disease management protocol but the eventual disease outcome as in this case died (8.4%), discharged (45.6%) was not linked to just one therapeutic factor but other indicators of disease severity such as positive chest CT findings (87.82%) have led to a poor disease prognosis which was noted in (28.9%) severe patients with GI symptoms compared to (71.1%) non-severe COVID-19 patients with GI symptom. Conclusion: Presence of GI symptoms in COVID-19 patients has shown to have a positive association with the poor disease prognosis likely as a result of direct viral toxicity. It is important for the physicians to recognize digestive symptoms as an important characteristic in COVID-19 patients. Hence, precise and targeted documentation of GI symptoms and viral stool sample investigations should be performed in order to understand the rapidly evolving disease symptomology.

Gastrointestinal Hemorrhage Due to Duodenal Varix: A Case Report.

We report a case of a 72-year-old female with a past medical condition of non-alcoholic steatohepatitis who presented in the emergency department with altered mentation. An Esophagogastroduodenoscopy was performed which showed a normal esophagus and stomach, but revealed grade III varices which were appreciable in the second portion of the duodenum. Her colonoscopy report revealed multiple small and large mouthed diverticula in the sigmoid colon along with hematin throughout the colon, yet no evidence of active bleeding, mass or inflammation. We discuss the patient's rarity of the clinical entity, clinical development, and elements used for diagnosis along with the treatment modalities involved.

A Rare Presentation of Isolated Right Colon Ischemia: The Mass-Forming Variant.

Ischemic colitis (IC), the most common gastrointestinal ischemia, remains an enigmatic disease with a wide array of pathogenic mechanisms and injuries along with variable outcomes. Among this group, isolated right colon ischemia (IRCI) appears to be a distinct entity, with its own pathophysiology, clinical presentation, and higher morbidity and mortality compared to left-sided colitis. IRCI is the most common site of mass-forming ischemic colitis. Colonoscopy with biopsy remains the key to diagnosis for this former entity. IRCI management is the same as for other IC and complete resolution of the mass is expected within weeks.

A Review of Locomotion Systems for Capsule Endoscopy.

Wireless capsule endoscopy for gastrointestinal (GI) tract is a modern technology that has the potential to replace conventional endoscopy techniques. Capsule endoscopy is a pill-shaped device embedded with a camera, a coin battery, and a data transfer. Without a locomotion system, this capsule endoscopy can only passively travel inside the GI tract via natural peristalsis, thus causing several disadvantages such as inability to control and stop, and risk of capsule retention. Therefore, a locomotion system needs to be added to optimize the current capsule endoscopy. This review summarizes the state-of-the-art locomotion methods along with the desired locomotion features such as size, speed, power, and temperature and compares the properties of different methods. In addition, properties and motility mechanisms of the GI tract are described. The main purpose of this review is to understand the features of GI tract and diverse locomotion methods in order to create a future capsule endoscopy compatible with GI tract properties.

Impedance pH confirms the relationship between GERD and BMI.

BACKGROUND: During the last 20 years the prevalence of both gastroesophageal reflux disease (GERD) and obesity has been increasing in the United States. The pathophysiology of GERD is multifactorial and its relationship with obesity is still not well understood. AIM: To evaluate the association between BMI and GERD as detected by multichannel intraluminal impedance-pH (MII-pH) monitoring. METHODS: Retrospective review of 122 consecutive MII-pH studies of adult patients while on PPI therapy. Patients were divided into normal (BMI < 25), overweight (BMI ≥ 25 and <30) and obese (BMI ≥ 30). Reflux episodes were classified as acid reflux (AR), nonacid reflux (NAR), and total number of reflux episodes, as detected by MII-pH. We evaluated the symptoms associated with reflux by using the symptom index (SI). We also assessed the number of reflux episodes during recumbency and compared them in the different BMI groups. RESULTS: The total number of reflux episodes and NAR episodes increased significantly as BMI increased. There was no significant difference between groups in AR. Similarly, during recumbency, total number of reflux episodes increased significantly when BMI increased. For symptoms associated with reflux, SI was more likely to be positive in the obese group. CONCLUSIONS: This study shows a clear association between increased reflux as detected by MII-pH and higher BMI. Obesity not only increases the likelihood of reflux events, as shown in previous studies, but also makes it more likely that symptoms reported during MII-pH studies are actually due to MII detected reflux.

Swallow evaluation during multichannel intraluminal impedance and pH: an alternate method to assess esophageal transit.

BACKGROUND: Twenty-four-hour multichannel intraluminal impedance and pH (MII-pH) esophageal monitoring allows detection of both acid and nonacid gastroesophageal reflux episodes. The MII-pH catheter contains 6 impedance segments placed 3, 5, 7, 9, 15, and 17 cm above the lower esophageal sphincter (LES), plus a pH electrode at 5 cm. Multichannel intraluminal impedance and esophageal manometry (MII-EM) allows both functional and manometric evaluation of the esophagus. The MII-EM catheter contains 4 impedance measuring segments (5, 10, 15, and 20 cm above LES) and 5 solid state pressure transducers (within the LES and 5, 10, 15, and 20 cm above LES). Five milliliter saline boluses are given in the recumbent position when performing an MII-EM study. In our laboratory, all patients have an MII-EM study performed before an MII-pH study. In many laboratories, MII-pH is done without earlier MII-EM. AIM: To assess accuracy of swallows given before ambulatory MII-pH monitoring in detecting esophageal transit abnormalities. MATERIALS AND METHODS: Hundred consecutive adult patients, prospectively studied (64 female; mean age = 52.6 y), presenting to our laboratory for MII-EM and 24-hours MII-pH study, also received 10 saline swallows in the recumbent position at the beginning of the MII-pH study. Impedance for these swallows was assessed for the presence of complete or incomplete transit; defined as presence of bolus entry in the 17 cm segment and bolus exit in the 15, 9, and 5 cm segments; defined by a rise in impedance above 50% between baseline and the nadir, and remaining above this value for at least 5 seconds. Of 10 swallows, the presence of 8 or more complete swallows satisfies the MII-EM criterion for diagnosis of complete transit. These findings were blindly compared with those of the 10 saline swallows on the MII-EM study. RESULTS: In 93% of patients, the MII-pH swallows gave identical transit diagnosis to the MII-EM. In 2 patients, the diagnosis changed from incomplete transit on MII-EM to complete on MII-pH, and in 5 patients from complete transit on MII-EM to incomplete on MII-pH. With both methods, there were 64 patients with complete transit and 29 with incomplete transit. Thus, MII-pH swallows had a sensitivity of 94% and a specificity of 93% for detection of esophageal transit abnormalities.Comparing the swallow diagnosis for each patient, we found that there was a highly significant correlation (P < 0.0001) for the number swallows with complete (Pearson r = 0.89) and incomplete bolus transits (Pearson r = 0.89). There was also a significant correlation (P < 0.0001) in bolus transit time between both methods (Pearson r = 0.64). CONCLUSIONS: Use of 10 saline swallows at the beginning of MII-pH studies is accurate, missing bolus transit abnormality in only 2 of 100 patients. It is also highly sensitive and specific for detection of esophageal transit abnormalities. This method allows detection of patients in whom further evaluation of esophageal function may be warranted.

Arbaclofen placarbil decreases postprandial reflux in patients with gastroesophageal reflux disease.

OBJECTIVES: Arbaclofen placarbil (AP), previously designated as XP19986, is an investigational prodrug of the active R-isomer of baclofen, a gamma-aminobutyric acid agonist reflux inhibitor. The aim of this study was to assess the efficacy and safety of AP for decreasing meal-induced reflux episodes in patients with gastroesophageal reflux disease (GERD). METHODS: We conducted a multicenter, randomized, double-blind, crossover study comparing single doses of AP with placebo. Different patients were enrolled at each of four escalating AP doses: 10, 20, 40, and 60 mg. Enrolled patients had GERD symptoms at least three times a week and 20 reflux episodes on impedance/pH monitoring over a period of 2 h. During study visits separated by periods of 3-7 days, patients received single doses of AP or placebo, followed by high-fat meals 2 and 6 h after treatment. The primary end point was the number of reflux episodes over 12 h after treatment. RESULTS: A total of 50 patients were treated; efficacy analysis included 44 patients who received both AP and placebo and had technically satisfactory impedance/pH data. For the combined data from all dose cohorts, there was a statistically significant (P=0.01) decrease in reflux episodes over 12 h after treatment with AP compared with placebo. The mean (s.d.) number of reflux episodes over 12 h after AP treatment was 50.5 (27.2), with a mean reduction of 10.4 (23.9) episodes (17%) compared with placebo, for which a mean (s.d.) number of 60.9 (35.3) episodes was observed. Heartburn events associated with reflux were reduced during treatment with AP compared with placebo. AP seemed to be the most efficacious in the 60-mg dose group, and was well tolerated at all dose levels. CONCLUSIONS: AP decreased reflux and associated symptoms with good tolerability in patients with GERD.

An analysis of distal esophageal impedance in individuals with and without esophageal motility abnormalities.

BACKGROUND: Combined multichannel intraluminal impedance and manometry provides simultaneous evaluation of bolus transit and pressure changes within the esophagus. The aim of this study was to analyze and to compare distal esophageal impedance values between healthy volunteers and patients with normal and abnormal esophageal manometry. MATERIALS AND METHODS: We analyzed multichannel intraluminal impedance and manometry studies in 130 individuals (79 women, mean age 53 y, age range 17 to 85 y). There were 20 healthy volunteers and 20 patients with normal manometry. Patients with abnormal manometry were separated into nutcracker esophagus (n=20), distal esophageal spasm (n=20), ineffective esophageal motility (IEM, n=20), achalasia (n=20), and scleroderma esophagus (n=10). Manometric and MII parameters were assessed during 10 liquid and 10 viscous swallows. MII findings included esophageal impedance values and number of complete and incomplete bolus transits (CBTs). Esophageal impedance values from 2 distal impedance measuring segments (5 and 10-cm above lower esophageal sphincter) were assessed over a 2 to 3 seconds interval before the first liquid and the first viscous swallow, and 2 to 3 seconds after the tenth viscous swallow. The average values of esophageal impedance measured at 5 and 10-cm above lower esophageal sphincter (distal esophageal impedance) were calculated before liquid [distal baseline impedance (DBI)] and after 10 liquid swallows [distal liquid impedance (DLI)] and after 10 viscous swallows [distal viscous impedance (DVI)]. The correlations between DLI and DVI and number of CBT for liquid and viscous as well as distal esophageal amplitude (DEA) for liquid and viscous were also assessed using Pearson correlation coefficient. RESULTS: Patients with achalasia or scleroderma esophagus had significantly lower DBI, DLI, and DVI than healthy volunteers, patients with normal manometry, nutcracker esophagus, or distal esophageal spasm. Patients with IEM had significantly lower DBI, DLI, and DVI than healthy volunteers or patients with nutcracker esophagus. Patients with IEM had significantly lower DLI and DVI than patients with normal manometry and significantly higher DVI than patients with achalasia. Overall, there was a significant correlation between DLI and CBTs during 10 liquid swallows (r=0.7, P<0.0001), DVI and CBTs during 10 viscous swallows (r=0.6, P<0.0001), DLI and DEA during 10 liquid swallows (r=0.5, P<0.0001), and DVI and DEA during 10 viscous swallows (r=0.5, P<0.0001). CONCLUSIONS: Our results suggest that evaluation of distal esophageal impedance may assist in recognition and diagnosis of esophageal motility abnormalities.

Revised criterion for diagnosis of ineffective esophageal motility is associated with more frequent dysphagia and greater bolus transit abnormalities.

BACKGROUND: Ineffective esophageal motility (IEM) has been defined by the presence of > or = 30% liquid swallows with contraction amplitude < 30 mmHg (ineffective swallows) in the distal esophagus ("old" IEM). A recent study with combined multichannel intraluminal impedance and manometry (MII-EM) raised the question whether the manometric diagnosis of IEM should be based on a new definition: > or = 50% ineffective liquid swallows ("new" IEM). The aim of this study was to evaluate the association between the number of ineffective liquid swallows and symptoms and bolus transit in patients with "new" or "old" IEM who underwent MII-EM studies using 10 liquid and 10 viscous swallows. MATERIALS AND METHODS: There were 150 patients with "old" IEM included in the study. The patients diagnosed with "old" IEM (N = 150) (group A) were compared with those who retained a manometric diagnosis of IEM by the new definition (N = 101) (group B). The patients who did not retain their manometric diagnosis of IEM by the new definition (N = 49) (group C) were compared with group B. IEM was characterized as mild (normal bolus transit for both liquid and viscous swallows), moderate (abnormal bolus transit either for liquid or viscous swallows), or severe (abnormal bolus transit for both liquid and viscous swallows). RESULTS: There was no statistical difference in frequency of mild, moderate, or severe IEM and frequency of symptoms between group A and B. Group C had a significantly higher frequency of mild IEM and significantly lower frequency of severe IEM than group B. Heartburn (25.7%vs 10.2%, P= 0.03) and dysphagia (24.8%vs 12.3%, P= 0.08) showed a trend towards a greater frequency in group B than in group C. CONCLUSION: Our study indicates that IEM with > or = 50% ineffective liquid swallows is frequently associated with bolus transit abnormalities and esophageal symptoms. Our results underscore the rationale for using the new definition of IEM.

Manometry and impedance characteristics of achalasia. Facts and myths.

BACKGROUND: Achalasia is defined manometrically by an aperistaltic esophagus. Variations in the manometric findings occur in achalasia suggesting that all manometric features should not be required to diagnose achalasia. Combined multichannel intraluminal impedance and esophageal manometry (MII-EM) allows both a functional and a manometric evaluation of esophageal motility and identifies chronic fluid retention. AIM: To compare manometric and MII characteristics in patients with achalasia. METHODS: Retrospective review of 73 MII-EM tracings from patients with achalasia done in our laboratory between October 2001 and December 2004 (38 females; mean age=53.5 y). Patients with previous esophageal interventions were excluded. Manometric and MII characteristics were identified and compared during 10 liquid and 10 viscous swallows. Patients were also divided into 2 groups: vigorous achalasia (VA) and achalasia. RESULTS: Twenty-two of the seventy-one (31%) achalasia patients had a hypertensive lower esophageal sphincter (LES). The mean lower esophageal sphincter pressure (LESP) for the 71 patients with achalasia was 37.9+/-21.2 mm Hg compared with 27.3+/-9.3 mm Hg (P<0.05) in the 73 patients with normal motility. The mean LESP in patients with achalasia was 36+/-20.3 mm Hg compared with 47+/-23.2 mm Hg (P<0.05) in patients with VA. Elevated intraesophageal pressure (IEP) was noted in 45/73 (61.6%). The mean LESP in this group was 41.1+/-22.9 mm Hg compared with 32.5+/-17 mm Hg (P<0.05) with normal IEP. The mean baseline impedance for achalasia was 801+/-732 compared with 1265.2+/-829.5 Omega (P<0.05) for the VA patients. CONCLUSIONS: Most patients with achalasia have elevated IEP, elevated LES residual pressure, normal LES pressure, and low baseline impedance. All manometric features should not be required to diagnose achalasia. Patients with an elevated IEP are likely to have an elevated LES pressure and LES residual pressure. Low MII values identify chronic fluid retention and helps confirm the diagnosis.

Normal values for manometry performed with swallows of viscous test material.

OBJECTIVE: Esophageal function testing with combined multichannel intraluminal impedance and manometry (MII-EM) is performed using ten 5-ml liquid and viscous swallows. Diagnosis of bolus transit abnormalities identified by impedance is based on both liquid and viscous swallows. Manometric diagnosis is based solely on liquid swallows. The aim of this study was to establish the normal values for manometry performed with a viscous bolus. MATERIAL AND METHODS: MII-EM studies performed in 80 healthy volunteers were analyzed. The analyzed manometric parameters included contraction amplitude and duration, distal onset velocity and lower esophageal sphincter (LES) residual pressure. RESULTS: Mean distal esophageal amplitude (DEA) (mmHg) for liquid swallows was 104 (+/-44) and for viscous swallows 102 (+/-51). Viscous versus liquid swallows were characterized by higher contraction amplitudes at 10 cm above the LES, slower distal onset velocities and higher LES residual pressures. Duration of contractions was similar between liquid and viscous swallows. Upper normal limits for viscous swallows were: 204 mmHg for DEA (mean+/-2 SDs); 6 ineffective and 1 simultaneous swallows and 11.7 mmHg for LES residual pressure (95th percentile). CONCLUSIONS: Based on our results, the following values should be considered normal for manometry performed with viscous swallows:

Impedance manometry with viscous test solution increases detection of esophageal function defects compared to liquid swallows.

OBJECTIVE: Multichannel intraluminal impedance and manometry (MII-EM) is performed using ten 5-ml swallows each of a liquid and a viscous solution. However, the manometric diagnosis is based solely on results from the 10 liquid swallows. The aim of this study was to compare esophageal function evaluated with 10 liquid versus 10 viscous swallows using combined MII-EM in patients with various symptoms. MATERIAL AND METHODS: Consecutive studies performed in 300 patients (211F, mean age 54.5 years) were analyzed. The manometric diagnoses were separated into normal and abnormal manometry. MII findings included the number of complete and incomplete transits and total bolus transit time. RESULTS: Manometric diagnosis for liquid and viscous solutions was consistent in 231 (77%) and inconsistent in 69 (23%) patients (p<0.0001). Overall, the number of manometric abnormalities detected with the viscous solution (n=91, 30.3%) was significantly higher (p=0.03) than that detected with the liquid solution (n=60, 20%). Impedance diagnosis for the viscous and liquid solutions was consistent in 238 (79.3%) patients and inconsistent in 62 (20.7%) patients (p<0.0001). Among those 62 patients, 36 (58.1%) had complete bolus transit with the liquid solution and incomplete bolus transit with the viscous solution, and 26 (41.9%) had incomplete bolus transit with the liquid solution and complete transit with the viscous solution (p=0.46). Overall, there was no significant difference between the number of bolus transit abnormalities for the liquid (n=75, 25%) and viscous solutions (n=85, 28.3%, p=0.47). CONCLUSIONS: Our results indicate that a viscous solution detects significantly more manometric abnormalities than a liquid solution. Impedance diagnosis has greater similarity for both the liquid and viscous solutions.

Bethanechol improves smooth muscle function in patients with severe ineffective esophageal motility.

BACKGROUND: There is no therapeutic intervention that reliably restores smooth muscle contractility for patients with ineffective esophageal motility (IEM). Bethanechol, a direct-acting muscarinic receptor agonist, has been shown in healthy volunteers to produce a significant increase in peristaltic amplitude in the distal esophagus. AIM: To identify whether bethanechol improves smooth muscle contractility and bolus transit in patients with IEM. METHODS: Seven patients diagnosed with severe IEM documented by combined multichannel intraluminal impedance and esophageal manometry were asked to participate. IEM was defined by using the new proposed criteria of greater than or equal to 50% saline swallows with contraction amplitude <30 mm Hg either 5 and/or 10 cm above the lower esophageal sphincter (LES). In the supine position, the patients were given 10 swallows of 5 mL of normal saline then 10 swallows of viscous solution, each 20 to 30 seconds apart. Patients were then given 50 mg oral bethanechol. After 20 and 40 minutes, 5 swallows of saline and viscous solution were repeated. Studies were then analyzed by an investigator blinded to the relationship of bethanechol administration to the swallows. The analysis included measurement of distal esophageal amplitude (DEA) or the mean amplitude at 5 and 10 cm above the LES. RESULTS: The use of bethanechol significantly increased (P<0.05) the esophageal contraction pressures at 5 and 10 cm above the LES. The DEA increased (P<0.05) for liquid and viscous, 20 minutes after its administration. Forty minutes after bethanechol administration, DEA and also individual pressures at 5 and 10 cm above the LES were still increased (P<0.05) for liquid, but only the DEA increased (P<0.05) with viscous solution. There was also a significant increase in complete bolus transit for saline swallows, both 20 and 40 minutes (P=0.03 and 0.01, respectively) after bethanechol. CONCLUSIONS: Oral bethanechol significantly improves contraction pressures and bolus transit in the smooth muscle portion of the esophagus in patients with severe IEM.

Combined multichannel intraluminal impedance and pH esophageal testing compared to pH alone for diagnosing both acid and weakly acidic gastroesophageal reflux.

BACKGROUND & AIMS: Twenty-four-hour multichannel intraluminal impedance and pH (MII-pH) esophageal monitoring detects reflux episodes at all pH levels, including acid reflux and weakly acidic reflux (WAR). The aim of this study was to assess the accuracy of pH monitoring alone in detecting acid reflux and WAR compared with MII-pH. METHODS: For the detection of acid reflux: 60 consecutive MII-pH studies of patients off acid suppression were included. All studies initially were read by exclusively analyzing pH tracing for acid reflux episodes. Subsequently, all studies were blindly read again analyzing MII-pH-detected acid reflux episodes (pH decrease of <4 and MII-detected reflux). For the detection of weakly acidic reflux 40 MII-pH studies were included. Each study initially was read by identifying WAR on the pH tracing. Subsequently, studies were re-analyzed using MII tracings, classifying MII-detected reflux episodes into acid, WAR, or nonacid reflux. RESULTS: For the detection of acid reflux the pH alone compared with MII-pH yielded a specificity of 68%, 67%, and 58%, respectively, for either abnormal percentage time of pH less than 4, positive symptom index, or both. The percentage time that the pH was less than 4 was significantly higher using pH alone compared with MII-pH. Eighty-one percent of acid gastroesophageal reflux episodes exclusively detected by pH were associated with MII-detected swallow. For the detection of WAR compared with MII, pH alone had a sensitivity of only 28%. Eighty-three percent of WAR episodes detected by pH were not associated with MII-detected reflux. CONCLUSIONS: The use of pH alone for the detection of acid reflux is very sensitive but lacks specificity compared with MII-pH. pH alone may overdiagnose abnormal acid reflux in up to 22% of tested patients. Also, the use of pH for the detection of WAR has poor sensitivity.

Postprandial stomach contents have multiple acid layers.

GOALS: The purpose of this study was to evaluate patterns in gastric pH both fasting and postprandially in different body positions. STUDY: Ten healthy volunteers were studied. A pH probe was positioned with an electrode 15 cm below the lower esophageal sphincter proximal border then withdrawn 1 cm every 30 seconds to 5 cm above the lower esophageal sphincter. Volunteers were tested on 2 occasions. Initially, they were studied in a semirecumbent position (45 degrees), with the first pull-through after 6 hour fasting. After a meal, a pull-through was repeated 4 consecutive times (approximately 15, 30, 45, and 60 min). On a subsequent day, the positions were changed with each pull-through: upright, supine, right decubitus, and left decubitus. The order of these positions was randomly selected. RESULTS: The pH step-up is defined as a change in pH from a gastric to an esophageal pH (<4-->>4). No significant difference was found between location of the pH step-up in the fasting and postprandial pull-throughs. An area of lower pH was consistently found within 2 cm distal to the step-up area. Distal to the area of higher gastric pH (median pH at 5), a second acid layer was found. This pattern persisted through the 4 postprandial pull-throughs, irrespective of body position. CONCLUSIONS: The pH step-up was persistent in the fasting period and for 1 hour postprandially, but did not migrate proximally. Gastric buffering from a meal creates a nonuniform environment with at least 2 acid layers. This pattern is present irrespective of body position. The lack of homogeneity of stomach content postprandially helps to explain the observation of occasional persistent acid gastroesophageal reflux after a meal.

Clinical relevance of the nutcracker esophagus: suggested revision of criteria for diagnosis.

BACKGROUND: Nutcracker esophagus (NE) is a manometric finding defined by peristaltic contractions with a mean distal esophageal amplitude (DEA) >180 mm Hg. This threshold has been selected as it exceeds the average DEA in healthy volunteers by 2 SDs. Since its introduction the clinical significance of this finding has been challenged, as many patients with NE are asymptomatic. AIM: To evaluate whether defining NE based on a different DEA threshold would be clinically more meaningful. METHODS: Retrospective review of prospectively collected manometry data between October 2001 and December 2003. Using previously published normal DEA values (mean and SD) patients with NE were stratified into 3 groups: group A (2 to 3 SD above mean): DEA 180 to 220 mm Hg; group B (3 to 4 SD above mean): DEA 220 to 260 mm Hg; and group C (>4 SD above mean): DEA >260 mm Hg. Symptoms, esophageal acid exposure, bolus transit data, and lower esophageal sphincter data were reviewed. RESULTS: The stratification of 56 NE patients into groups A, B, and C were 31, 16, and 9, respectively. The proportion of patients presenting with chest pain increased from 23% in group A to 69% in group B and 100% in group C. Patients in group C had significantly (P<0.05) higher mean lower esophageal sphincter pressure, shorter bolus transit time, and lower frequency of abnormal reflux. CONCLUSIONS: A revised definition of NE to include patients with a DEA >260 mm Hg, and possibly those with >220 may have greater clinical relevance.

Ingestion of acidic foods mimics gastroesophageal reflux during pH monitoring.

Ingestion of acidic foods may produce artifactual drops in pH to < 4 that may be difficult to differentiate from a true acid reflux event. We aimed to evaluate intraesophageal pH changes during the ingestion of acidic food and describe the frequency and implications of acidic food ingestion on ambulatory pH monitoring. Ten normal volunteers (six females; mean age, 34) underwent combined impedance-pH testing with a pH electrode placed 5 cm above the lower esophageal sphincter. Each volunteer received 50 ml each of acidic foods in random order. Nadir and mean pH for 30 sec after ingestion of each substance were recorded. Subsequently 100 randomly selected reflux monitor diaries were reviewed, searching for ingestion of acidic foods, and 100 pH tracings were reviewed to evaluate the impact of including/excluding meal periods on percentage time pH < 4 and DeMeester scores. All foods produced abrupt drops to pH < 4, in 80% of cases exceeding 30 sec. During ambulatory pH monitoring 78% of patients recorded ingestion of at least 1 of the 10 tested substances during meals, the majority admitting ingesting carbonated beverages. Not excluding meal periods would have led to the misinterpretation of 6-16% of tracings, depending on the criteria used to identify abnormal acid exposure. We conclude that ingestion of acidic foods is frequent and carries the risk of overdiagnosing GERD. Current findings support the recommendations to carefully instruct patients to record all oral intake and to exclude meal periods from the analysis.