Thangam Venkatesan

Background Cyclic vomiting syndrome (CVS) can impair nutritional status due to recurrent episodes of nausea and vomiting, yet systematic data are lacking. We aimed to evaluate nutritional status in adults with CVS using validated assessment tools. Methods In a prospective study of adults diagnosed with CVS based on Rome IV criteria, nutritional status was evaluated using the Patient-Generated Subjective Global Assessment Short Form (PG-SGA-SF) completed by participants, the PG-SGA completed by a Registered Dietitian Nutritionist (RDN) and the Malnutrition Screening Tool (MST). Key Results Among 80 participants (mean age 39 ± 16 years) 77.5% (n = 62) were female, and 85% (n = 68) had moderate-to-severe CVS. Based on the PG-SGA-SF, 70% (n = 56) were at risk of malnutrition (42.5%, n = 34 severe; 27.5%, n = 22 moderate). More than half (41; 51%) were at risk for malnutrition (MST score ≥ 2). Despite this, 27% (n = 22) were obese, and 20% (n = 16) were overweight. Mean BMI did not differ between well-nourished and malnourished participants (28.4 ± 8.2 kg/m² vs. 29.1 ± 7.7; p = 0.7). Of the 64 participants with a completed PG-SGA, 62.5% were classified as malnourished (28%, n = 18 severe; 34%, n = 22 moderate). The PG-SGA-SF demonstrated high sensitivity (100%) and specificity (71%) for detecting malnutrition with a positive predictive value of 85% and a negative predictive value of 100%. Conclusions and Inferences Most adults with CVS met criteria for malnutrition, indicating a need for referral to an RDN. BMI should not be used as a screening tool for malnutrition, and mechanisms underlying obesity in CVS warrant further investigation.

Background: In cyclic vomiting syndrome (CVS), approximately 30% of patients remain symptomatic between episodes. We hypothesized that avoidance of presumed food triggers contributes to avoidant/restrictive food intake disorder (ARFID) and is associated with nutritional consequences in adults with CVS. Methods: We prospectively studied adults diagnosed with CVS who completed the Nine‐Item ARFID Screen (NIAS), Eating Disorder Questionnaire (EDE‐QS), Food Security Questionnaire, and the VioScreen food frequency questionnaire. Nutrition status was assessed by a registered dietitian nutritionist (RDN). Key Results: Among 80 participants (mean age 39 ± 16 years; 77.5% female), 30 (37.5%) screened positive for ARFID risk (NIAS+). Eight patients (10%) screened positive for eating disorder risk as well and were excluded from analyses. Those at risk for ARFID (NIAS+) were younger (32 ± 11 vs. 46 ± 16 y), had moderate–severe CVS (90% vs. 10%), anxiety (67% vs. 38%), depression (66% vs. 33%), reported more inter‐episodic symptoms, and used cannabis more often (50% vs. 30%) (all p < 0.05), though cannabis‐use disorder was not higher in this group. Those at risk for ARFID were more likely to be malnourished (73% vs. 30%) and at risk for food insecurity (30% vs. 0%) (both p < 0.001). These participants also consumed fewer calories and had several micronutrient intakes below recommendations. Conclusions and Inferences: About a third of patients with CVS screened positive for ARFID. This was associated with malnutrition and deficient intake of several micronutrients. Screening for ARFID, disordered eating, and food insecurity is warranted. RDN involvement in developing targeted interventions may impact nutritional outcomes.

Cyclic vomiting syndrome (CVS) and cannabinoid hyperemesis syndrome (CHS) are emerging gastroduodenal disorders with a growing prevalence. However, little is known about their prevalence and clinical characteristics in Latin American populations, particularly in Mexico. This study aims to explore the clinical presentation of CVS and CHS in Mexico. A cross-sectional study was conducted in 5 medical centers across Mexico, involving patients diagnosed with CVS or CHS based on the Rome IV criteria. Data collected included sociodemographic variables, substance use, comorbidities, and clinical characteristics, with a specific focus on the relationship between substance use, particularly cannabis, and symptomatology. The study included 46 patients, with 30 diagnosed with CVS and 16 with CHS. CVS patients were younger (median age 23 years) compared to CHS patients (median age 27 years; P = 0.043). CHS patients exhibited higher tobacco consumption (50.0% vs 26.7%; P = 0.019) and risky alcohol use (31.3% vs 0.0%; P = 0.003). Cannabis use was reported by 13.3% of CVS patients. The time to diagnosis was longer for CVS (35.4 ± 9.8 months) compared to CHS (26.5 ± 16.0 months; P = 0.016). No significant differences were found in the number of hospital admissions, as well as length of stay between patients with CVS and CHS. This study presents the first detailed analysis of CVS and CHS in the Mexican population, revealing some demographic and clinical differences from global data. These findings highlight the importance of developing region-specific guidelines for diagnosing and managing these conditions, especially given Mexico's changing cannabis policies.

Background: Cyclic vomiting syndrome (CVS) is a disorder characterized by sudden, recurrent episodes of severe nausea and vomiting. The pathophysiology of CVS is not known but genetic factors that regulate emetic neurocircuitry have been proposed. The aim of this study was to investigate whether different variations in genes encoding serotonin receptors (HTRs) are associated with susceptibility to CVS and/or CVS symptoms.Methods: This case–control study included 70 patients with CVS:16 male and 54 female, and 2504 healthy controls from the 1000 Genomes Project database. Single‐nucleotide polymorphisms (SNPs) in genes encoding serotonin receptors (HTR1B, HTR1D, HTR3B and HTR3C) and correlations between SNPs and the symptoms of CVS were determined.Key Results: Our study discovered that patients with GG, AA and GG genotypes of HTR1B/D rs6296, rs6298 and rs6300, respectively, as well as the CC genotype of HTR3B rs176744 are associated with an increased risk (p < 0.001), whereas allele C in rs3788987 (HTR3B, p < 0.01) and allele A in rs6766410 (HTR3C, p < 0.05) were associated with a decreased risk of CVS. In addition, statistical analysis indicated that CVS patients with GA or AA genotypes of HTR1D rs676643 gene have a seven‐fold increase in risk of depression compared to patients with GG genotype (p < 0.01).Conclusions and Inferences: Our study revealed for the first time that variations in 5‐HTR genes may contribute to CVS susceptibility and CVS‐related symptoms.

Background: Data are limited on the natural history and symptom patterns of cyclic vomiting syndrome (CVS), a disorder of gut–brain interaction characterized by recurrent stereotypical vomiting, retching, and nausea episodes.Methods: A 6‐month, observational, remote study prospectively assessed symptom patterns in adults with CVS using an electronic daily diary. Patients recorded their disease experience, including CVS symptoms and associated severity, in the daily diary. The study defined a CVS episode start as the first day of 5 or more vomiting and/or retching (V + R) events. Episode end was defined as the first day of ≥ 7 (prespecified main analysis) or ≥ 4 (sensitivity analysis) days without any diary V + R events.Key Results: Eighty‐eight of 93 (94.6%) enrolled patients (62 female; mean age, 37.7 years) had daily diary data recorded during the study; 61 (69.3%) patients had at least one episode. In the prespecified main analysis, 191 episodes (median, 0.6 per 30 diary days) were reported (median duration, 3.0 days); 17.8% of the episodes lasted > 10 days. In the sensitivity analysis, 248 episodes (median, 0.7 per 30 diary days) were reported (median duration, 2.0 days). Thirteen of 88 (14.8%) patients with diary data had interepisodic V + R (reported V + R events without meeting the threshold for study‐defined episode). Other CVS‐related (non‐V + R) symptoms (most frequently nausea, abdominal pain, and sweating) were reported more frequently during the episode versus the interepisodic period.Conclusions and Inferences: This prospective longitudinal study shows marked heterogeneity of CVS episodes and highlights the need to better define and characterize episodes in these patients.

Background: Cyclic vomiting syndrome is a chronic disorder of gut‐brain interaction that is present in both adults and children. It is characterized by severe nausea, vomiting, abdominal pain, and several non‐GI symptoms. It is also associated with several comorbid conditions such as anxiety and depression, which affect overall health care outcomes.Methods: This article delineates treatment principles, encompassing both abortive interventions and prophylactic regimens currently recommended for CVS. However, it underscores a critical concern: the absence of FDA‐approved medications for CVS treatment, with existing therapies relying on retrospective and open‐labeled trials.Key results: This article emphasizes the pressing need for the development of CVS‐specific outcome assessment tools to facilitate more accurate evaluation and robust data collection for the future studies. In exploring this deficiency, the manuscript also presents the up‐to‐date data and development that enhances our comprehension of patient‐centric concepts, and the challenges faced in creating CVS‐specific tools, and presents a roadmap for their development. Addressing this gap is crucial for advancing our understanding of CVS and optimizing patient care.Conclusions and Inferences: This elucidates the current state of CVS management but also advocates for a future where tailored tools enhance our ability to measure and improve the outcomes for individuals with this debilitating disorder.

Background: Classical antiemetics that target the serotonin system may not be effective in treating certain nausea and vomiting conditions like cyclic vomiting syndrome (CVS) and cannabinoid hyperemesis syndrome (CHS). As a result, there is a need for better therapies to manage the symptoms of these disorders, including nausea, vomiting, and anxiety. Cannabis is often used for its purported antiemetic and anxiolytic effects, given regulation of these processes by the endocannabinoid system (ECS). However, there is considerable evidence that cannabinoids can also produce nausea and vomiting and increase anxiety in certain instances, especially at higher doses. This paradoxical effect of cannabinoids on nausea, vomiting, and anxiety may be due to the dysregulation of the ECS, altering how it maintains these processes and contributing to the pathophysiology of CVS or CHS.Purpose: The purpose of this review is to highlight the involvement of the ECS in the regulation of stress, nausea, and vomiting. We discuss how prolonged cannabis use, such as in the case of CHS or heightened stress, can dysregulate the ECS and affect its modulation of these functions. The review also examines the evidence for the roles of ECS and stress systems' dysfunction in CVS and CHS to better understand the underlying mechanisms of these conditions.

Background: Cannabis use in the general population is prevalent and is rising because of increased acceptance of its use, legalization in most US states, and perceived health benefits. Cannabis product potency has dramatically increased with higher delta‐9‐tetrahydrocannabinol content. Cannabis has documented antiemetic properties and cannabinoid pharmaceuticals are used in disorders like chemotherapy‐induced nausea and vomiting.Purpose: Forty to eighty percent of cyclic vomiting syndrome (CVS) patients use cannabis products, which reportedly reduce stress as well as nausea and vomiting. Cannabinoid hyperemesis syndrome (CHS) has a presentation similar to CVS, but is associated with longstanding, high dose cannabis use, and is thought to be relieved by sustained cannabis abstinence. Most CHS patients have used cannabis on a daily or near‐daily basis for more than 2 years. Compulsive hot‐water bathing behaviors are reported by most CHS patients, but are not specific for this disorder as they are also noted by about half of CVS patients. Episodic vomiting associated with cannabis use contributes to extensive health resource use, including emergency department visits and inpatient hospitalizations, and impacts patients and their families negatively. Treatment for CHS overlaps with CVS although cannabis abstinence remains the cornerstone of its management. Challenges associated with cannabis use cessation in CHS include patient skepticism of the role of cannabis as a cause of symptoms, perceived benefits of cannabis, and a lack of other effective therapies. In this review, we highlight cannabis use patterns in the US and discuss diagnosis and management of CHS and gaps in knowledge about this disorder.