Journal of Diabetology

REVIEW ARTICLE
Year
: 2021  |  Volume : 12  |  Issue : 3  |  Page : 263--269

Role of wireless motility capsule in diagnosing diabetic gut autonomic neuropathy: A narrative review


Ravi Kant1, Poonam Yadav2,  
1 Division of Diabetes and Metabolism, General Medicine
2 College of Nursing, All India Institute of Medical Sciences, Rishikesh, Uttarakhand, India

Correspondence Address:
Mrs. Poonam Yadav
College of Nursing, All India Institute of Medical Sciences, Rishikesh, Uttarakhand.
India

Abstract

Gastroparesis is known as delayed gastric emptying in the absence of mechanical obstruction, typical symptoms being nausea, vomiting, bloating, early satiety, and upper abdominal pain. Gastroparesis is much prevalent in type 2 diabetes mellitus patients. Currently, methods used for the assessment of gastrointestinal (GI) motility involve radiation and invasiveness and are mostly limited to regional assessment, with a lengthy hospital stay, and most of the tests are even not standardized. Gastric emptying scintigraphy (GES) using a radiolabeled meal is the gold standard diagnostic test used to detect and quantify gastroparesis. The advantages of this test are physiological, economical, and non-invasive characteristics. However, lack of standardization poses radiation exposure. As diabetic patients already suffer from diabetic complications and comorbidities, availability of diagnostic tests by offering a non-radioactive, standardized, and ambulatory investigation may be a better alternative to GES to prevent unnecessary radiation exposure. This review summarizes the role of wireless motility capsule (WMC) in diagnosing gut diabetic autonomic neuropathy. The WMC is a novel technology that allows the physician to measure GI motility in a convenient, ambulatory, relatively non-invasive way, without exposing the patient to radiation. The WMC also established its diagnostic utility to assess diabetic gastroparesis in many multicentric studies; although it has some contraindications and limitations, it is the best available novel technology for diagnosing gut diabetic autonomic neuropathy.



How to cite this article:
Kant R, Yadav P. Role of wireless motility capsule in diagnosing diabetic gut autonomic neuropathy: A narrative review.J Diabetol 2021;12:263-269


How to cite this URL:
Kant R, Yadav P. Role of wireless motility capsule in diagnosing diabetic gut autonomic neuropathy: A narrative review. J Diabetol [serial online] 2021 [cited 2021 Dec 2 ];12:263-269
Available from: https://www.journalofdiabetology.org/text.asp?2021/12/3/263/327320


Full Text



 Introduction



Diabetes mellitus (DM) is the most common non-communicable disease (NCD) worldwide.[1] In 2019, there are more than 463 million cases of type 2 diabetes worldwide, which is expected to increase to 700 million by 2045, especially in low- and middle-income countries due to lack of physical activity and overweight people.[2],[3] In India, diabetes is expected to cross nearly 123.5 million by 2040.[2] In recent years, Krentz et al.[4] and Al-Wakeel et al.[5] reported that complications also develop simultaneously with diabetes. Although glycemic control may reduce the development of associated microvascular (neuropathy, nephropathy, and retinopathy) and macrovascular complications (cardiovascular disease, stroke, and peripheral vascular disease), it is still progressing and requires focussed management of these complications simultaneously with the treatment of diabetes.[6] A study conducted in four continents such as Asia, Africa, Europe, and South America reported macrovascular complication prevalence as 27.2% and microvascular complication as 53.5%. Among the Southeast Asian population, the prevalence of macrovascular complications was 23.3%, and microvascular complications were 39%.[7]

It was also found that diabetes duration has a linear relationship with the development of a microvascular complication. According to the researcher, 25–40% of the patients with more than five years of diabetes duration develop microvasculopathy simultaneously with diabetes.[8]

It was observed in a study conducted in Sri Lanka that diabetic neuropathy is the most common complication of diabetes, and its prevalence was noted as 80.5% with more than 15 years of diabetes duration.[9] Diabetes neuropathy is one of the microvascular complications which is responsible for morbidity and mortality in diabetes patients. Diabetes autonomic neuropathy may affect the gastrointestinal (GI) systems, cardiovascular system, neuroendocrine system, and genito-urinary system.[10],[11] Diabetes gastroparesis is described as delayed gastric emptying in the absence of mechanical obstruction, typical symptoms being nausea, vomiting, bloating, early satiety, and upper abdominal pain.[12] The prevalence of gastroparesis in type 2 DM is estimated to be 30–40% and 1% in hospital-based and community-based studies, respectively.[13] In a case series of 146 patients with type 2 DM from India, the prevalence of delayed gastric emptying was 29%.[14] In the North Indian region Lucknow, it was estimated as 29.2%, and in the North Eastern region, it was observed as 29.0%.[15],[16] A study conducted in India’s capital region among 720 patients also found a prevalence of 15.3%.[17] The true prevalence of gastroparesis in diabetic patients is unknown and varies widely among various studies conducted across the world. Diabetes gastroparesis results from a dysfunction in the coordination of the autonomic nervous system, neurons, and specialized pacemaker cells of the GI tract’s stomach and intestine.[12] DM is the most commonly associated known systemic disease with gastroparesis, the most common cause of gastroparesis being idiopathic.[18] Due to these non-specific yet bothersome symptoms, patients frequently visit their physicians. Patients are often under-evaluated partly due to the non-specific nature of symptoms, lack of adequate infrastructure available in government setups for a thorough evaluation of diabetic gastroparesis, and non-affordability of patients’ private health setups. Therefore, the objective severity of gastroparesis in patients is frequently unknown in most cases. One of the complications arising from long-standing diabetes is gastroparesis as a result of autonomic neuropathy.[13]

In the long term, patients with gastroparesis suffer from malnutrition and an increased risk of hospitalizations.[13] Early detection of gastroparesis and timely intervention may significantly improve the quality of life of the patients, which will decrease the number of hospital visits[16] and, thus less loss of work-days of people which poses an extra financial burden to the patients added to the difficulties of unfavorable weather and geographic conditions while traveling.[19]

Several types of gastric emptying patterns have been observed for liquids, digestible solids, and non-digestible solids food items, and several types of methods are available to assess the GI tract function.[20] Gastric emptying scintigraphy (GES) using a radiolabeled meal is the gold standard diagnostic test used to detect and quantify gastroparesis; the advantages of this test are physiological, economical, non-invasive, and sensitive. However, the drawbacks are the lack of standardization between two different centers and radiation exposure.[21],[22] As diabetic patients already suffer from diabetic complications and comorbidities, diagnostic tests’ availability by offering a non-radioactive, standardized, and ambulatory investigation may be a better alternative to GES to prevent the patients from unnecessary radiation exposure.[23] This review aims to summarize the role of wireless motility capsule (WMC) in diagnosing gut diabetic autonomic neuropathy.

 Currently Used Methods for the Assessment of GI Tract Function



Methods routinely involve radiation exposure, invasiveness, and are mostly limited to one GI tract region assessment, require more time for hospital stay, and some of the tests are often not standardized. Although the cost of WMCs is relatively high than other methods used to diagnose gastroparesis, its benefits outweigh the cost in diabetic patients [Table 1].[20]{Table 1}

 Description of WMC



Any novel technique for diagnosing dysmotility must have several essential characteristics. First, it should measure motor function, whose natural limitations are known and well-rounded from the disease. Secondly, it must be standardized, reproducible, and easily understood, and finally, it must be acceptable by patients. These characteristics negate the fact that only relatively few techniques have been established in clinical practice, such as esophageal manometry, colonic manometry, radio-opaque markers (ROM), and GES.[24],[25] The WMC is a novel, ambulatory, non-invasive, and non-radioactive device that concurrently measures intraluminal pressure, temperature, and pH through its movement in the GI tract. This capsule transmits the data at regular intervals to a portable receiver worn by the patient. A complete appraisal of upper and lower GI motility may give necessary target information to help diagnose and plan therapeutic strategies.[26] It is US FDA-approved for evaluating suspected gastroparesis and colonic transit in the setting of chronic constipation.[25] Besides, WMC has been validated as an objective measure of GI transit by the American and European Neurogastroenterology and Motility Societies.[27]

 Description of WMC System



The WMC system consists of an indigestible single-use capsule [Figure 1], an external data receiver [Figure 2], and analysis software [Figure 3]. Capsule and receiver have a battery life of 5 days after activation of the system.[28] The capsule measures 26 mm × 13 mm, and sensors are placed to measure pH, temperature, and pressure. It can measure a temperature range between 25°C and 49°C. The temperature sensor has an accuracy of ±0.5°C, pH sensor ±0.5 pH units, and pressure ±5mmHg below 100mmHg.[29] It also encompasses a small encapsulated video camera placed to catch images of the small bowel, approximately 50,000–60,000 digital images for each case, reducing redundancy in wireless capsule endoscopy videos.[27] The test allows the clinicians to monitor pH and pressure throughout the regional or whole GI tract without radiation. These measurements are used to calculate the gastric emptying time (GET), whole gut transit time (WGTT), small bowel transit time (SBTT), and colonic transit time (CTT) and to evaluate motility disorders such as nausea, bloating, heartburn, constipation, and feeling of fullness while eating food. These are most common symptoms of a motility disorder such as diabetic gastroparesis and chronic constipation.[26]{Figure 1} {Figure 2} {Figure 3}

The capsule flows through the GI tract and collects pressure, pH, and temperature data. After ingesting the capsule, a data receiver worn on a belt records all the capsule’s information. Sensors placed within the capsule continuously measure pH, pressure, and temperature for up to 5 days of ingestion as the capsule moves through the entire gut to provide transit and pressure information. Data are downloaded in a computer, providing physicians with the GI transit information to evaluate the stomach, small bowel, and colon. The hospital visit will require approximately 30 min, after which time patients can resume their normal daily activities.[29]

 Preparation for Investigation



The patient will be asked to maintain overnight fasting before the procedure. Certain drugs such as prokinetics, antidiarrheal, laxatives, histamine receptor antagonists, proton pump inhibitors, and antacids that may affect the gastric pH and motility should be discontinued before the test [Figure 4].[27]{Figure 4}

It is required to obtain informed consent from the patient before initiating the procedures. The patient is asked to have a standardized meal SmartBar (17% protein, 66% carbohydrate, 2% fat, and 3% fiber) or equivalent in nutritional such as an egg sandwich (255kcal, 2% fat, 1g fiber) with 120mL of water.[29] After that, WMC is given to the patient to swallow with 50mL of water. An acidic pH is being recorded on the portable external recorder (which suggests passage of the capsule into the stomach) for the successful introduction of WMC. The patient is asked to wear this device typically for 5 days. The external data receiver also allows that the patient is instructed to keep the data recorder close to the patient’s abdomen during the first 6 h of the procedure when the WMC is in the stomach to record symptoms, meals, sleep, and bowel movements electronically. Patients should be instructed to keep the data receiver within the area of 5ft of their own when the patient does not wear it. Patients can be discharged from the hospital after the successful ingestion of a capsule. However, he/she is not allowed to eat anything for the next 6 h to effectively establish the fasting motility pattern. After that, patients may be allowed to resume their regular diet and daily activities but instructed to avoid heavy physical exercise during the 5 days of the investigation. After that period, the investigator will collect the patient’s data; downloaded data of 5 days will be automatically analyzed using a software package. When the capsule has not been excreted out in 5 days, a “live” monitoring feature can be utilized in certain conditions. This feature allows the investigator to review the data to check the location of the capsule. If capsule excretion is not confirmed, the investigator may carry out an abdominal radiograph to confirm its location. In case of retention of the capsule, a stimulant laxative may be administered to expel WMC.[27]

 Transit Periods



Temperature, pH, and pressure profiles are used to calculate GET, SBTT, CTT, and WGTT. GET is referred to as the time from ingestion of the capsule to the abrupt pH rise from baseline to a pH >4, signaling the capsule’s passage from the acidic to the alkaline environment.[30] The SBTT is referred to as the abrupt drop of at least 1 pH unit, at least 30 min after GET, that is maintained for a minimum of 10 min.[31] CTT is usually seen as an entry of the capsule into the colon until expulsion with a significant temperature drop. WGTT can be evaluated after combining GET, SBTT, and CTT. The normative reference data for transit times using the WMC of GET for >4 h suggest delayed gastric emptying, the normal range for SBTT is 2.5–6 h, CTT >59 h indicates delayed colonic transit, and WGTT is normal <73 h [Figure 5].[32],[33]{Figure 5}

 Diagnostic Utility of WMC



Sangnes et al.[34] performed a study in 72 diabetic gastroparesis patients to compare WMC with GES. They found that WMC had a sensitivity of 0.92, specificity 0.73, accuracy 0.80, the ordinary cutoff for delayed gastric emptying (300 min), whereas GES had sensitivity 0.92, specificity 0.83, and accuracy 0.86 at cutoff value for delayed gastric emptying of 385 min. It shows the utility of WMC as a reliable test to assess gastric emptying in diabetic gastroparesis patients. Lee et al.[35] conducted a multicenter clinical trial in 167 gastroparesis patients; 53 of them had diabetes for 3 years. WMC only diagnosed regional and generalized transit abnormalities in 61.8% of the patients. WMC diagnosed delayed gastric emptying more frequently in comparison to GES and also recognized extra-gastric transit abnormalities. Hasler et al.[36] performed a multicentric study in 150 patients with gastroparesis symptoms simultaneously with GES and WMC to assess the needs for an additional diagnostic evaluation with these tests. Results show that additional diagnostic tests were not required with WMC in comparison to GES (71% vs. 31%) (P < 0.0001). Zikos et al.[37] performed a retrospective study among 27 females to assess the diagnostic utility of WMC in patients with postural tachycardia syndrome. Fourteen patients had postural tachycardia syndrome-delayed small bowel transit (42.9% vs. 7.69%, P = 0.037), and the other 13 patients had mild autonomic abnormalities. Findings suggested that WMC offers an additional opportunity to assess patients with autonomic dysfunction and postural tachycardia syndrome. Irshad et al.[38] also found in 6 years prospective study that 48% of the patients with upper GI symptoms had gastroparesis, and 23% of the patients with lower GI symptoms had slow transit constipation. In this study, the result showed new diagnostic information that in 45% of the patients with lower GI symptoms, only half had a prolonged CTT. It indicates that patients with suspected gastroparesis should be tested for the whole GI tract, as presenting symptoms may be poor predictors of the affected gut region. WMC was also used to compare DET and SBTT in critically ill patients and healthy volunteers and established its efficacy in these patients.[37] A prospective study was performed with 83 patients of suspected gastroparesis to define generalized dysmotility prevalence with WMC testing. Testing observed regional delays by 32% compared with conventional tests, and it showed new diagnoses in 53%. WMC testing modified 67% of patients’ management, including starting new medications, their nutritional regimens, and eliminating needs for other testing such as gastric scintigraphy, small bowel barium transit, and radio-opaque colon marker tests.[39]

 Contraindications to WMC Testing



The WMC testing is contraindicated for the use of patients under the age of 18, Crohn’s disease, gastric bezoar, diverticulitis, any swallowing disorder, and intestinal obstruction. WMC testing is also contraindicated in patients with implanted cardiac pacemaker, defibrillator, and infusion pumps.[40]

According to a trial of 209 patients with gastroparesis symptoms, maintenance drugs such as antihypertensive and antidepressants also influenced the reporting and may be responsible for retention of the capsule; similarly, recording of the glycemic index was also crucial in diabetic patients during that period, which may influence the gastric motility and produce false reporting.[39]

 Adverse Events with WMC



The adverse events associated with the WMC is the retention of the capsule within the body even after 5 days of investigation. In three multicenter trials, one serious adverse event was reported where the capsule failed to exit from the body in 5 days of investigation. After the endoscopic assessment, it was found that the patient had a gelatinous bezoar in the stomach. In other patients, the capsule successfully exited from the body within the range of 5–26 days. The majority of patients passed the capsule in 5 days only. Only 3% of the patients were shown to have an inability to swallow the capsule, and 7.2% of the patients reported the malfunction in software.[40],[41],[42],[43] The manufacturer company reports a capsule retention rate of 0.33% after post-market analysis of 6000 capsules. Only 20 reports showed prolonged capsule retention. Endoscopic capsule retrieval was performed for only five patients. In the remaining cases, no intervention was performed, and spontaneous expulsion had been observed.[40] A study with 61 gastroparesis patients and 87 healthy subjects reported 10 adverse events. Six events were not concerned with a device, three were probably not related, and one was related. Two of the reported events were episodes of vomiting, which took place after ingesting the capsule, but the capsule did not expel out vomitus. Another adverse event was reported in a patient after he/she had ingested laxatives. The capsule could not be retrieved even after performing an endoscopy, and then erythromycin 200 mg i.v. was administered, and the capsule subsequently emptied.[21]

 Conclusion



Currently, methods used for the assessment of GI tract function involve radiation, invasiveness, and mostly limited to regional assessment, require a lengthy hospital stay, and some of the tests are even not standardized. GES using a radiolabeled meal is considered the gold standard diagnostic test used to detect and quantify gastroparesis. The advantages of this test are physiological, economical, and non-invasive. However, this test’s drawbacks are the lack of standardization between two different centers and radiation exposure. As diabetic patients already suffer from diabetic complications and comorbidities, availability of diagnostic tests by offering a non-radioactive, standardized, and ambulatory investigation may be a better alternative to GES to prevent the patients from unnecessary radiation exposure. The WMC is a novel technology that allows the physician to measure GI motility in a convenient, ambulatory, relatively non-invasive way, without exposing the patient to radiation. The WMC also had established its diagnostic utility to assess diabetic gastroparesis in many multicentric studies. As diabetic patients are already carrying the burden of diabetes and its complication that affects the quality of life of those patients also, in such a situation, the benefits of WMC outweigh its cost in diabetes patients. In view of its contraindications and limitations relatively, WMC is the best available novel technology for gut diabetic autonomic neuropathy. It is needed to focus on developing a low-cost WMC for its maximum utilization in resource-limited countries and conducting studies to assess its feasibility at secondary and tertiary care hospitals.

Financial support and sponsorship

None.

Conflicts of interest

There are no conflicts of interest.

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