Cyclic vomiting syndrome: Future clinical and research priorities for: Special supplement/proceedings of 3rd international symposium.

BACKGROUND: An increasing number of studies have explored the clinical features, epidemiology, pathophysiology, and management of cyclic vomiting syndrome (CVS). CVS is common in adults and children and negatively impacts patients, families, and the healthcare system. A related condition, cannabinoid hyperemesis syndrome (CHS), has been a focus of interest in the lay press and published literature. PURPOSE: Clinical presentations of CVS have been defined by small series and expert opinion, but recent prospective studies are refining our understanding of the spectrum of emetic episodes and the breadth of comorbid conditions. Large cross-sectional population analyses are clarifying CVS prevalence and factors related to age, ethnicity, and geographic region. CVS pathophysiology is multifactorial with contributions from migraines, dysautonomia, endogenous cannabinoids, mitochondrial dysfunction, genetic abnormalities, and rapid gastric emptying. CVS treatment relies on antiemetics and antimigraine therapies to abort acute episodes coupled with prophylactic regimens employing neuromodulators and antiepileptics. CHS represents a challenge partly because of difficulties in achieving sustained cannabis abstinence. Benefits of other therapies in CHS remain poorly defined. Several areas warrant further scrutiny including better identification of CVS triggers and characterization of different CVS subsets including those with frequent severe episodes, refined description of epidemiology to allow targeting of populations predisposed to CVS development, rigorous definition of pathogenic factors to provide a foundation for exploratory studies of novel therapies, and conduct of controlled trials by multicenter collaborations to confirm benefits of existing and new therapies in development. Progress in these areas will be facilitated by generous governmental and industry support.

Suboptimal Performance of Microscopic Colitis Diagnosis Codes: A Bottleneck for Epidemiologic Insights.

INTRODUCTION: Administrative health data could contribute to generalizable microscopic colitis insights, but International Classification of Diseases (ICD) codes for microscopic colitis have not been validated. METHODS: We identified individuals who received care for diarrhea in the Veterans Health Administration and classified them by receipt of microscopic colitis ICD codes. We reviewed random samples of charts to calculate the positive predictive value (PPV) and negative predictive value (NPV). We then calculated the sensitivity and specificity in clinically relevant cohorts. RESULTS: The PPV was 0.790 and the NPV was 0.995. In a cohort of individuals with diarrhea who underwent colonoscopy, the sensitivity and specificity were 0.734 and 0.996, respectively. CONCLUSION: Alternative ascertainment methods for microscopic colitis are needed because ICD codes have suboptimal performance.

Epidemiology, Comorbidities, and Treatment of Cyclic Vomiting Syndrome in the United States.

INTRODUCTION: Cyclic vomiting syndrome (CVS) imposes a substantial burden, but epidemiological data are scarce. This study aimed to estimate the incidence and prevalence of CVS, comorbid conditions, and treatment patterns, using administrative databases in the United States. METHODS: This cross-sectional study used claims data from Merative MarketScan Commercial/Medicare Supplemental and Medicaid databases in all health care settings. Incidence and prevalence rates for 2019 were calculated and stratified by age, sex, region, and race/ethnicity. Patient characteristics were reported among newly diagnosed patients with CVS (i.e., no documented claims for CVS before 2019). CVS was defined as having 1+ inpatient and/or 2+ outpatient CVS claims that were 7+ days apart. RESULTS: The estimated prevalence of CVS was 16.7 (Commercial/Medicare) and 42.9 (Medicaid) per 100,000 individuals. The incidence of CVS was estimated to be 10.6 (Commercial/Medicare) and 26.6 (Medicaid) per 100,000 individuals. Both prevalence and incidence rates were higher among female individuals (for both Commercial/Medicare and Medicaid). Comorbid conditions were common and included abdominal pain (56%-64%), anxiety (32%-39%), depression (26%-34%), cardiac conditions (39%-42%), and gastroesophageal reflux disease (30%-40%). Despite a diagnosis of CVS, only 32%-35% had prescriptions for prophylactic treatment and 47%-55% for acute treatment within the first 30-day period following diagnosis. DISCUSSION: This study provides the first population-level estimates of CVS incidence and prevalence in the United States. Comorbid conditions are common, and most patients with CVS do not receive adequate treatment. These findings underscore the need for improving disease awareness and developing better screening strategies and effective treatments.

Nightshade Vegetables: A Dietary Trigger for Worsening Inflammatory Bowel Disease and Irritable Bowel Syndrome?

The Solanaceae family of plants, commonly known as Nightshade vegetables or Nightshades, contains a diverse range of crops of over 2000 members with significant culinary, economic, and cultural importance. Familiar edible Nightshades include tomatoes, peppers, eggplants, and white potatoes. Many pharmacologically active compounds used in traditional medicine, including atropine and hyoscyamine, are derived from Nightshades. In addition to these beneficial pharmacologic agents, Nightshade-derived glycoalkaloid compounds, a key defense mechanism against predation, have been shown to disrupt intestinal epithelium and to potentially activate mast cells in the gut mucosa, leading to adverse symptoms in humans. There is a new appreciation that mast cell activation is an allergic inflammatory mechanism contributing both to pain in irritable bowel syndrome (IBS) and to gut inflammation in inflammatory bowel disease (IBD). Given their ubiquity in Western diets and their shared glycoalkaloid active compounds, edible Nightshades are attracting new interest as a potential trigger for worsening gut symptoms in functional and inflammatory gastrointestinal disorders. Here, we review the limited existing literature on the adverse effects of Nightshade consumption, including the effects of Nightshade-derived glycoalkaloids on IBD gut inflammation, and the under-recognized contribution of Nightshades to food allergies and allergic cross-reactivity. We then highlight new evidence on the contributions of mast cell activation to GI disorder pathogenesis, including potential linkages between Nightshade antigens, intestinal mast cells, and GI dysfunction in IBS and IBD.

Understanding Our Tests: Hydrogen-Methane Breath Testing to Diagnose Small Intestinal Bacterial Overgrowth.

There is increasing appreciation that small intestinal bacterial overgrowth (SIBO) drives many common gastrointestinal symptoms, including diarrhea, bloating, and abdominal pain. Breath testing via measurement of exhaled hydrogen and methane gases following ingestion of a readily metabolized carbohydrate has become an important noninvasive testing paradigm to help diagnose SIBO. However, because of a number of physiological and technical considerations, how and when to use breath testing in the diagnosis of SIBO remains a nuanced clinical decision. This narrative review provides a comprehensive overview of breath testing paradigms including the indications for testing, how to administer the test, and how patient factors influence breath testing results. We also explore the performance characteristics of breath testing (sensitivity, specificity, positive and negative predictive values, likelihood ratios, and diagnostic odds ratio). Additionally, we describe complementary and alternative tests for diagnosing SIBO. We discuss applications of breath testing for research. Current estimates of SIBO prevalence among commonly encountered high-risk populations are reviewed to provide pretest probability estimates under a variety of clinical situations. Finally, we discuss how to integrate breath test performance characteristics into clinical care decisions using clinical predictors and the Fagan nomogram.

Development and Assessment of a Low Literacy, Pictographic Cyclic Vomiting Syndrome Action Plan.

OBJECTIVE: To develop and assess an evidence-based, individualized Cyclic Vomiting Syndrome Action Plan (CVSAP) to optimize both preventative and acute care. STUDY DESIGN: This implementation science project synthesized a combination of clinical practice guidelines, published literature, and clinical experience by a team of CVS clinicians to develop the CVSAP. The tool was developed to include validated pictograms and an automatic, embedded, weight-based dosing calculator to output acute management recommendations. The final version of the CVSAP was tested by patients/caregivers, readability calculators, medical librarians, and clinicians using validated metrics. RESULTS: All pictograms met the criteria for inclusion in the CVSAP. A composite readability score of 5.32 was consistent with a fifth-grade level. Patients/caregivers (n = 70) judged the CVSAP to be of high quality with consumer information rating form rating of 84.2%. Six medical librarians rated the CVSAP to have 93% understandability and 100% actionability, and 33 clinicians completing the SAM generated a suitability rating of 87.5%. CONCLUSIONS: The CVSAP visually highlights individualized care plan components to facilitate optimized preventative and acute CVS care. Further investigation will determine if CVSAP increases caregiver confidence and compliance in home management and improves quality of life and clinical outcomes for patients with CVS.

A Coached Digital Cognitive Behavioral Intervention Reduces Anxiety and Depression in Adults With Functional Gastrointestinal Disorders.

INTRODUCTION: Traditional cognitive behavioral interventions (CBIs) improve mood and gastrointestinal symptom severity in patients with functional gastrointestinal disorders (FGIDs) but face substantial barriers to implementation. Integrating behavioral health technology into medical clinic workflows could overcome these barriers. We evaluated the feasibility and impact of a coached digital CBI (dCBI) as a first-line intervention in a prospective cohort of emotionally distressed patients with FGID. METHODS: Patients with anxiety and/or depressive symptoms were offered a dCBI (an app called RxWell) during routine clinic visits. RxWell provides cognitive behavioral techniques enhanced by within-app text messaging with a health coach. Both gastroenterology and behavioral health-care providers electronically prescribed RxWell. We tracked patient interactions with RxWell, and patients completed anxiety (General Anxiety Disorder-7) and depression (Personal Health Questionniare Depression Scale) measures through the app. Our primary study outcome was the change in General Anxiety Disorder-7 and Personal Health Questionniare Depression Scale scores. RESULTS: Of 364 patients with FGID (mean age 43 years [SD 16 years]; 73.1% women) prescribed the dCBI, 48.4% enrolled (median use, 3 techniques [interquartile range 1-14]). About half of RxWell enrollees communicated with health coaches. The mean baseline anxiety score was 11.4 (SD 5.5), and the depression score was 11.5 (SD 6.1). RxWell users experienced improvements in anxiety (mean change 2.71 [t = 3.7, df = 58; P < 0.001]) and depression (mean change 2.9 [t = 4.2, df = 45; P < 0.001]) at 4 months. DISCUSSION: Patients with FGIDs and moderately severe anxiety and depressive symptoms are willing to use dCBI tools recommended by their providers. Our pilot data demonstrate that dCBI usage is associated with clinically and statistically significant mood symptom reductions.

Greater intolerance to uncertainty predicts poorer quality of life in adults with cyclic vomiting syndrome.

BACKGROUND: Cyclic vomiting syndrome (CVS) is an idiopathic disorder of gut-brain interaction characterized by recurrent bouts of nausea and vomiting. Although CVS negatively impacts quality of life (QOL), the determinants of impaired QOL among adult CVS sufferers are not fully understood. The unpredictability of CVS attacks may generate anticipatory anxiety and worsen quality of life in a substantial proportion of patients with CVS. Intolerance to uncertainty (IU) is a cognitive trait in which individuals experience distress when faced with unpredictable situations, particularly those with potentially negative consequences. Higher trait IU is a well-established vulnerability factor linked to the development of multiple psychiatric conditions, including anxiety. However, the extent to which higher IU is associated with impaired QOL in adults with CVS is not known. METHODS: To explore this issue, we surveyed 118 adult CVS patients and obtained demographic information, clinical features, reported healthcare utilization, and standardized assessments of IU, anxiety and panic, and QOL. KEY RESULTS: Adult CVS patients with higher IU did not report a greater frequency of CVS attacks or overall CVS-related healthcare utilization than those with lower IU. Yet, this group demonstrated substantially poorer physical and mental health-related QOL and higher rates of anxiety-spectrum disorders. CONCLUSIONS & INFERENCES: Higher degrees of IU are associated with increased anxiety and reduced QOL in patients with CVS. IU is a malleable cognitive trait that can be targeted by cognitive behavioral therapy (CBT). Our results suggest that some CVS patients may benefit from non-pharmacologic therapies such as CBT.

Improvement of Cyclic Vomiting Syndrome with Outpatient Ketamine Infusions.

Cyclic vomiting syndrome (CVS) is a disorder characterized by recurrent flares of nausea and vomiting, often with significant abdominal pain, of several days duration. Although traditional prophylactic and abortive treatments for CVS are often successful, a subset of CVS patients with chronic abdominal pain may not respond as well to standard therapies. This report is the first, to our knowledge, to describe the use of outpatient ketamine infusions as therapy for refractory CVS. We describe a 63-year-old woman with history of CVS who presented with abdominal pain and recurrent episodes of nausea and vomiting. She first received ketamine during an inpatient admission for a CVS flare, with the aim of treating the abdominal pain. Given her improvement, she was offered a series of outpatient ketamine infusions, which led to a significant reduction in her symptoms. Thus, ketamine may be useful as both an abortive and prophylactic therapy in CVS. Prior reports have noted the anti-emetic effects of ketamine in the perioperative setting, and there is emerging evidence for the use of ketamine infusions for the treatment of chronic pain. However, this report is the first to describe ketamine as a potential prophylactic treatment for CVS.

Clinical Characteristics of Inflammatory Bowel Disease Patients Requiring Long-Term Parenteral Support in the Present Era of Highly Effective Biologic Therapy.

BACKGROUND: Despite advances in the medical management of inflammatory bowel disease (IBD), a subset of patients may require extensive surgery, leading to short-bowel syndrome/intestinal failure requiring long-term home parenteral nutrition (PN) or customized intravenous fluid (IVF) support. Our aim was to further define the characteristics of IBD patients requiring home PN/IVF. METHODS: This is an observational study from a prospective IBD research registry. Patients receiving long-term home PN/IVF support during 2009-2015 were identified and compared with remaining IBD patients. Demographics, surgical history, smoking, narcotic use, IBD treatment, healthcare charges, and presence of biomarkers were reviewed. The IBD-PN group was stratified into 3 groups based on median healthcare charges. RESULTS: Of 2359 IBD patients, there were 25 (1%, 24 with Crohn's disease) who required home PN/IVF, and 250 randomly selected IBD patients matched for disease type formed the control population. Median duration of PN use was 27 months (interquartile range, 11-66). PN use was significantly associated with smoking, narcotic use, IBD-related operations, and lower quality-of-life scores. Among IBD-PN patients, 7 of 25 (28%, 3 after use of teduglutide) were able to successfully discontinue this modality. Median healthcare charges in the IBD-PN group were $51,456 annually. Median charges in the controls were $3427. Period prevalence mortality was 11.5% in IBD-PN and 3.8% in controls. CONCLUSIONS: IBD patients requiring long-term home PN/IVF support are a small minority in the present era of immunomodulator/biologic therapy. These refractory patients have a 15-fold increase in annual median healthcare charges compared with control IBD patients.

Multiple areas of the cerebral cortex influence the stomach.

The central nervous system both influences and is influenced by the gastrointestinal system. Most research on this gut-brain connection has focused on how ascending signals from the gut and its microbiome alter brain function. Less attention has focused on how descending signals from the central nervous system alter gut function. Here, we used retrograde transneuronal transport of rabies virus to identify the cortical areas that most directly influence parasympathetic and sympathetic control of the rat stomach. Cortical neurons that influence parasympathetic output to the stomach originated from the rostral insula and portions of medial prefrontal cortex, regions that are associated with interoception and emotional control. In contrast, cortical neurons that influence sympathetic output to the stomach originated overwhelmingly from the primary motor cortex, primary somatosensory cortex, and secondary motor cortex, regions that are linked to skeletomotor control and action. Clearly, the two limbs of autonomic control over the stomach are influenced by distinct cortical networks.

The mind-body problem: Circuits that link the cerebral cortex to the adrenal medulla.

Which regions of the cerebral cortex are the origin of descending commands that influence internal organs? We used transneuronal transport of rabies virus in monkeys and rats to identify regions of cerebral cortex that have multisynaptic connections with a major sympathetic effector, the adrenal medulla. In rats, we also examined multisynaptic connections with the kidney. In monkeys, the cortical influence over the adrenal medulla originates from 3 distinct networks that are involved in movement, cognition, and affect. Each of these networks has a human equivalent. The largest influence originates from a motor network that includes all 7 motor areas in the frontal lobe. These motor areas are involved in all aspects of skeletomotor control, from response selection to motor preparation and movement execution. The motor areas provide a link between body movement and the modulation of stress. The cognitive and affective networks are located in regions of cingulate cortex. They provide a link between how we think and feel and the function of the adrenal medulla. Together, the 3 networks can mediate the effects of stress and depression on organ function and provide a concrete neural substrate for some psychosomatic illnesses. In rats, cortical influences over the adrenal medulla and the kidney originate mainly from 2 motor areas and adjacent somatosensory cortex. The cognitive and affective networks, present in monkeys, are largely absent in rats. Thus, nonhuman primate research is essential to understand the neural substrate that links cognition and affect to the function of internal organs.

Cyclic vomiting syndrome: Pathophysiology, comorbidities, and future research directions.

Cyclic vomiting syndrome (CVS) is characterized by severe episodic emesis in adults and children. Cannabinoid hyperemesis syndrome is an increasingly recognized CVS-like illness that has been associated with chronic cannabis use. There are significant gaps in our understanding of the pathophysiology, clinical features, comorbidities, and effective management options of CVS. Recommendations for treating CVS are based on limited clinical data, as no placebo-controlled, randomized trials have yet been conducted. Diseases associated with CVS, including migraine, mitochondrial disorders, autonomic dysfunction, and psychiatric comorbidities, provide clues about pathophysiologic mechanisms and suggest potential therapies. We review our current understanding of CVS and propose future research directions with the aim of developing effective therapy. Establishing a multicenter, standardized registry of CVS patients could drive research on multiple fronts including developing CVS-specific outcome measures to broaden our understanding of clinical profiles, to serve as treatment end points in clinical trials, and to provide a platform for patient recruitment for randomized clinical trials. Such a robust database would also facilitate conduct of research that aims to determine the underlying pathophysiological mechanisms and genetic basis for CVS, as well as identifying potential biomarkers for the disorder. Soliciting government and industry support is crucial to establishing the necessary infrastructure and achieving these goals. Patient advocacy groups such as the Cyclic Vomiting Syndrome Association (CVSA), which partner with clinicians and researchers to disseminate new information, to promote ongoing interactions between patients, their families, clinicians, investigators, to support ongoing CVS research and education, must be an integral part of this endeavor.

Management of cyclic vomiting syndrome in adults: Evidence review.

BACKGROUND: This evidence review was conducted to inform the accompanying clinical practice guideline on the management of cyclic vomiting syndrome (CVS) in adults. METHODS: We followed the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) framework and focused on interventions aimed at prophylactic management and abortive treatment of adults with CVS. Specifically, this evidence review addresses the following clinical questions: (a) Should the following pharmacologic agents be used for prophylaxis of CVS: amitriptyline, topiramate, aprepitant, zonisamide/levetiracetam, or mitochondrial supplements? (b) Should the following pharmacologic agents be used for abortive treatment: triptans or aprepitant? RESULTS: We found very low-quality evidence to support the use of the following agents for prophylactic and abortive treatment of CVS: amitriptyline, topiramate, aprepitant, zonisamide/levetiracetam, and mitochondrial supplements. We have moderate certainty of evidence for the use of triptans as abortive therapy. We found limited evidence to support the use of ondansetron and the treatment of co-morbid conditions and complementary therapies. CONCLUSIONS: This evidence review helps inform the accompanying guideline for the management of adults with CVS which is aimed at helping clinicians, patients, and policymakers, and should improve patient outcomes.

Role of chronic cannabis use: Cyclic vomiting syndrome vs cannabinoid hyperemesis syndrome.

Cannabis is commonly used in cyclic vomiting syndrome (CVS) due to its antiemetic and anxiolytic properties. Paradoxically, chronic cannabis use in the context of cyclic vomiting has led to the recognition of a putative new disorder called cannabinoid hyperemesis syndrome (CHS). Since its first description in 2004, numerous case series and case reports have emerged describing this phenomenon. Although not pathognomonic, a patient behavior called "compulsive hot water bathing" has been associated with CHS. There is considerable controversy about how CHS is defined. Most of the data remain heterogenous with limited follow-up, making it difficult to ascertain whether chronic cannabis use is causal, merely a clinical association with CVS, or unmasks or triggers symptoms in patients inherently predisposed to develop CVS. This article will discuss the role of cannabis in the regulation of nausea and vomiting, specifically focusing on both CVS and CHS, in order to address controversies in this context. To this objective, we have collated and analyzed published case series and case reports on CHS in order to determine the number of reported cases that meet current Rome IV criteria for CHS. We have also identified limitations in the existing diagnostic framework and propose revised criteria to diagnose CHS. Future research in this area should improve our understanding of the role of cannabis use in cyclic vomiting and help us better understand and manage this disorder.

Guidelines on management of cyclic vomiting syndrome in adults by the American Neurogastroenterology and Motility Society and the Cyclic Vomiting Syndrome Association.

The increasing recognition of cyclic vomiting syndrome (CVS) in adults prompted the development of these evidence-based guidelines on the management of CVS in adults, which was sponsored by the American Neurogastroenterology and Motility Society (ANMS) and the Cyclic Vomiting Syndrome Association (CVSA). GRADE (Grading of Recommendations, Assessment, Development, and Evaluation) framework was used and a professional librarian performed the literature search. The expert committee included the President of the CVSA who brought a patient perspective into the deliberations. The committee makes recommendations for the prophylaxis of CVS, treatment of acute attacks, diagnosis, and overall management of CVS. The committee strongly  recommends that adults with moderate-to-severe CVS receive a tricyclic antidepressant (TCA), such as amitriptyline, as a first-line prophylactic medication and receive topiramate or aprepitant as alternate prophylactic medications. Zonisamide or levetiracetam and mitochondrial supplements (Coenzyme Q10, L-carnitine, and riboflavin) are conditionally recommended as alternate prophylactic medications, either alone or concurrently with other prophylactic medications. For acute attacks, the committee conditionally recommends using serotonin antagonists, such as ondansetron, and/or triptans, such as sumatriptan or aprepitant to abort symptoms. Emergency department treatment is best achieved with the use of an individualized treatment protocol and shared with the care team (example provided). The committee recommended screening and treatment for comorbid conditions such as anxiety, depression, migraine headache, autonomic dysfunction, sleep disorders, and substance use with referral to appropriate allied health services as indicated. Techniques like meditation, relaxation, and biofeedback may be offered as complementary therapy to improve overall well-being and patient care outcomes.

Sympathetic Neuronal Activation Triggers Myeloid Progenitor Proliferation and Differentiation.

There is a growing body of research on the neural control of immunity and inflammation. However, it is not known whether the nervous system can regulate the production of inflammatory myeloid cells from hematopoietic progenitor cells in disease conditions. Myeloid cell numbers in diabetic patients were strongly correlated with plasma concentrations of norepinephrine, suggesting the role of sympathetic neuronal activation in myeloid cell production. The spleens of diabetic patients and mice contained higher numbers of tyrosine hydroxylase (TH)-expressing leukocytes that produced catecholamines. Granulocyte macrophage progenitors (GMPs) expressed the ß2 adrenergic receptor, a target of catecholamines. Ablation of splenic sympathetic neuronal signaling using surgical, chemical, and genetic approaches diminished GMP proliferation and myeloid cell development. Finally, mice lacking TH-producing leukocytes had reduced GMP proliferation, resulting in diminished myelopoiesis. Taken together, our study demonstrates that catecholamines produced by leukocytes and sympathetic nerve termini promote GMP proliferation and myeloid cell development.