Quantitative Evaluation of Right Ventricular Workload Based on the Stroke Work Index in Patients after Right Ventricular Outflow Tract Reconstruction.

The evaluation of right ventricular workload is sometimes complicated in patients after right ventricular outflow tract reconstruction (RVOTR) because both stenotic and regurgitation lesions are involved. In this study, we modified the right ventricular stroke work index (RVSWI) and evaluated the relationship between the modified RVSWI (mRVSWI) and patient prognosis after RVOTR.We enrolled 69 patients who underwent RVOTR (the RVOTR group), including those who needed early reoperation (early reoperation subgroup) and those who did not (follow-up subgroup), and 13 age-matched control participants (control group). Based on the catheterization results 1 year after RVOTR, we compared the mRVSWI between these groups. Additionally, we evaluated the influence of the mRVSWI on the reoperation avoidance rate and survival.The mRVSWI in the RVOTR group was significantly greater than that in the control group (17.7 ± 8.6 vs. 11.0 ± 2.7 g·m/m2, p = 0.008). The mRVSWI in the early reoperation subgroup was significantly greater than that in the follow-up subgroup (32.5 ± 11.1 vs. 15.8 ± 6.0 g·m/m2, p < 0.0001). In the follow-up subgroup, patients with an mRVSWI higher than the upper limit of normal (16.4 g·m/m2) had a greater rate of reoperation than did the other patients (p = 0.0013). One patient died suddenly, and her mRVSWI was consistently high throughout her life.We established the mRVSWI as an index that integrates the pressure and volume load on the right ventricle. Our results indicate the utility of the mRVSWI for predicting patient prognosis after RVOTR.

Prenatal aortic arch development in double aortic arch: Understanding postnatal closure of left aortic arch: A case report.

Double aortic arch (DAA) is a rare congenital abnormality characterized by a vascular ring that often requires surgical intervention due to respiratory complications. The DAA and right aortic arch with mirror-image branches (RAA-MB) represent abnormalities in development of the aortic arch. However, prognosis differs significantly, as the DAA forms vascular rings, whereas the RAA-MB typically does not. Distinguishing between the conditions becomes particularly challenging in cases of DAA with closure of the posterior portion of the left aortic arch (LAA) because the postnatal manifestations closely resemble those of RAA-MB. Herein, we present a case of DAA in which longitudinal observation of the LAA and RAA diameters during pregnancy aimed in predicting postnatal closure of the LAA. A 37-year-old female with suspected DAA was referred to our hospital at 26 weeks of gestation. Initial measurements revealed comparable diameters for the LAA and RAA; however, the LAA diameter decreased to approximately half that of the RAA by term owing to growth restrictions. Postnatal contrast computed tomography confirmed the closure of the posterior portion of the LAA and RAA with Kommerell diverticulum. Our findings suggest that careful monitoring of DAA throughout fetal development, especially during the third trimester, may aid in predicting atretic changes in the nondominant arch after birth, allowing an easy distinction between the DAA and RAA-MB after birth.

Successful treatment of fulminant myocarditis due to COVID-19 in a 5-year-old girl.

Reports of acute myocarditis are increasing due to the worldwide spread of coronavirus disease 2019 (COVID-19). We report a case of a 5-year-old girl with fulminant myocarditis caused by COVID-19, who was successfully treated with veno-arterial extracorporeal membrane oxygenation (VA-ECMO). The unvaccinated patient had developed fever 1 week before attending our hospital and was "presumptive positive" for COVID-19 based on the surrounding infectious situation. The fever resolved, but the day before the visit, abdominal pain appeared. The patient visited her previous physician with vomiting as the main complaint. She was transferred to our hospital due to impaired consciousness and bradycardia, with a heart rate of 40 beats/min. Immediately after transfer, she was diagnosed with complete atrioventricular (AV) block and was scheduled to undergo percutaneous pacing lead insertion. However, the patient had ventricular tachycardia, AV block and hypotension intraoperatively and required cardiopulmonary resuscitation. The patient was in an extremely unstable circulatory state, and VA-ECMO was urgently introduced. After multidisciplinary treatment for acute myocarditis, waiting for an improvement in AV block, and recovery of cardiac function, the patient was weaned from VA-ECMO on the eighth day after admission. The patient was discharged with no cardiac or neurologic sequelae. Learning objective: The rapid introduction of veno-arterial extracorporeal membrane oxygenation for fulminant myocarditis caused by coronavirus disease 2019 (COVID-19) in young children is extremely effective. Vaccination may be important for preventing infection with COVID-19 and avoiding severe complications.

Fact-finding survey of doctors at the departments of pediatrics and pediatric surgery on the transition of patients with childhood-onset chronic disease from pediatric to adult healthcare.

BACKGROUND: The number of adult patients with childhood-onset chronic diseases is increasing. However, the process of transitioning these patients from child- to adult-centered medical services faces many difficulties. Despite the key role that doctors in the pediatric field are considered to play in transition, few fact-finding surveys about transition have been conducted among these doctors. OBJECTIVE: The aim of this study was to demonstrate the current status and challenges in the transition of patients with childhood-onset chronic diseases by a fact-finding survey of pediatricians and pediatric surgeons at a university hospital. METHODS: A cross-sectional survey was performed using an anonymous self-administered questionnaire. Seventy-six doctors of pediatrics and pediatric surgery (excluding junior residents) in a university hospital were asked to answer an anonymous self-report questionnaire. A multidisciplinary research team selected items related to the transitional process. RESULTS: Sixty (79%) doctors participated, of whom 52 (87%) showed awareness of transition. No doctor answered that "Transition is conducted smoothly." Doctors with shorter pediatric department experience had lower awareness and poorer experience with transition. In contrast to pediatric surgeons, pediatricians explained "job-seeking activities" and "contraceptive methods" to the patient, and reported a higher patient age at which to initiate explanation of transition to the patient and his/her family. Among factors inhibiting transition, 39 (65%) respondents selected "The patient's family members do not desire transition" and 34 (57%) selected "Although a relevant adult healthcare department is available, it will not accept the patient." The medical providers most frequently considered to have responsibility for playing a central role in the transition process were "pediatrician/pediatric surgeon," "medical social worker," and "regional medical liaison office." DISCUSSION: To promote transition, pediatric and adult healthcare departments should share concerns about and cooperate in the establishment of more effective methods of transition, and provide multidisciplinary collaboration to support patients and their families.

Switching to lemborexant for the management of insomnia in mental disorders: the SLIM study.

STUDY OBJECTIVES: We conducted a retrospective study to investigate the efficacy and safety of switching from other hypnotics, including benzodiazepines and Z-drugs, suvorexant, ramelteon, mirtazapine, trazodone, and antipsychotics, to lemborexant, a dual orexin receptor antagonist, for 3 months. METHODS: Clinical data obtained from the medical records of 61 patients treated at the Horikoshi Psychosomatic Clinic between December 2020 and February 2022 were analyzed, including the Athens Insomnia Scale, Epworth Sleepiness Scale, and Perceived Deficits Questionnaire-5. The primary outcome was the mean change in Athens Insomnia Scale score after 3 months. Secondary outcomes were the mean changes in the Epworth Sleepiness Scale and Perceived Deficits Questionnaire-5 scores over 3 months. We also compared pre- and post-diazepam equivalents. RESULTS: The mean Athens Insomnia Scale score decreased over 3 months after switching to lemborexant (1 mo: -2.98 ± 5.19, P < .001; 2 mo: -3.20 ± 5.64, P < .001; 3 mo: -3.38 ± 5.61, P < .001). Mean Epworth Sleepiness Scale score did not change from baseline to 1 month (-0.49 ± 3.41, P = 0.27), 2 months (0.082 ± 4.62, P = .89), or 3 months (-0.64 ± 4.80, P = .30). Mean Perceived Deficits Questionnaire-5 score did improve from baseline to 1 month (-1.17 ± 2.47, P = .004), 2 months (-1.05 ± 2.97, P = .029), and 3 months (-1.24 ± 3.06, P = .013). There was also a reduction in the total diazepam equivalent (baseline vs 3 mo: 14.0 ± 20.2 vs 11.3 ± 20.6, P < .001). CONCLUSIONS: Our study showed that, by switching to lemborexant from other hypnotics, the risks associated with benzodiazepines and Z-drugs may be reduced. CITATION: Horikoshi S, Miura I, Suzuki Y, et al. Switching to lemborexant for the management of insomnia in mental disorders: the SLIM study. J Clin Sleep Med. 2023;19(10):1753-1758.

NLRP3 Inflammasome Activation Through Heart-Brain Interaction Initiates Cardiac Inflammation and Hypertrophy During Pressure Overload.

BACKGROUND: Mechanical stress on the heart, such as high blood pressure, initiates inflammation and causes hypertrophic heart disease. However, the regulatory mechanism of inflammation and its role in the stressed heart remain unclear. IL-1ß (interleukin-1ß) is a proinflammatory cytokine that causes cardiac hypertrophy and heart failure. Here, we show that neural signals activate the NLRP3 (nucleotide-binding domain, leucine-rich-containing family, pyrin domain-containing 3) inflammasome for IL-1ß production to induce adaptive hypertrophy in the stressed heart. METHODS: C57BL/6 mice, knockout mouse strains for NLRP3 and P2RX7 (P2X purinoceptor 7), and adrenergic neuron-specific knockout mice for SLC17A9, a secretory vesicle protein responsible for the storage and release of ATP, were used for analysis. Pressure overload was induced by transverse aortic constriction. Various animal models were used, including pharmacological treatment with apyrase, lipopolysaccharide, 2'(3')-O-(4-benzoylbenzoyl)-ATP, MCC950, anti-IL-1ß antibodies, clonidine, pseudoephedrine, isoproterenol, and bisoprolol, left stellate ganglionectomy, and ablation of cardiac afferent nerves with capsaicin. Cardiac function and morphology, gene expression, myocardial IL-1ß and caspase-1 activity, and extracellular ATP level were assessed. In vitro experiments were performed using primary cardiomyocytes and fibroblasts from rat neonates and human microvascular endothelial cell line. Cell surface area and proliferation were assessed. RESULTS: Genetic disruption of NLRP3 resulted in significant loss of IL-1ß production, cardiac hypertrophy, and contractile function during pressure overload. A bone marrow transplantation experiment revealed an essential role of NLRP3 in cardiac nonimmune cells in myocardial IL-1ß production and cardiac phenotype. Pharmacological depletion of extracellular ATP or genetic disruption of the P2X7 receptor suppressed myocardial NLRP3 inflammasome activity during pressure overload, indicating an important role of ATP/P2X7 axis in cardiac inflammation and hypertrophy. Extracellular ATP induced hypertrophic changes of cardiac cells in an NLRP3- and IL-1ß-dependent manner in vitro. Manipulation of the sympathetic nervous system suggested sympathetic efferent nerves as the main source of extracellular ATP. Depletion of ATP release from sympathetic efferent nerves, ablation of cardiac afferent nerves, or a lipophilic ß-blocker reduced cardiac extracellular ATP level, and inhibited NLRP3 inflammasome activation, IL-1ß production, and adaptive cardiac hypertrophy during pressure overload. CONCLUSIONS: Cardiac inflammation and hypertrophy are regulated by heart-brain interaction. Controlling neural signals might be important for the treatment of hypertensive heart disease.

Relationship between high trait anxiety in 22q11.2 deletion syndrome and the difficulties in medical, welfare, and educational services.

Aim: The 22q11.2 deletion syndrome (22q11DS) is associated with a high prevalence of mental health comorbidities. However, not enough attention has been paid to the elevated prevalence of high trait anxiety that begins early in life and may be enduring. We sought to identify specific medical, welfare, or educational difficulties associated with high trait anxiety in 22q11DS. Methods: A questionnaire-based survey was conducted for the parents of 22q11DS individuals (N = 125). First, a multiple regression analysis was conducted to confirm the hypothesis that high trait anxiety in individuals with 22q11DS would be associated with parents' psychological distress. This was based on 19 questionnaire options regarding what difficulties the parents currently face about their child's disease, characteristics, and traits. Next, we explored what challenges faced in medical, welfare, and educational services would be associated with the trait anxiety in their child. Results: The multiple regression analysis confirmed that the high trait anxiety was significantly associated with parental psychological distress (ß = 0.265, p = 0.018) among the 19 clinical/personal characteristics of 22q11DS. Furthermore, this characteristic was associated with various difficulties faced in the medical care, welfare, and education services, and the parent-child relationship. Conclusion: To our knowledge, this is the first study to clarify quantitatively how the characteristic of high anxiety level in 22q11DS individuals is related to the caregivers' perceived difficulties in medical, welfare, and educational services. These results suggest the necessity of designing service structures informed of the fact that high trait anxiety is an important clinical feature of the syndrome.

Rapidly growing thrombus from a ductus arteriosus aneurysm in a neonate.

Ductus arteriosus aneurysm (DAA) is a rare cardiovascular anomaly, and thrombosis of DAA is even less common. The management of asymptomatic DAA with a thrombus is controversial. We here report a neonate with a thrombus from a DAA that grew rapidly into the pulmonary artery. The thrombus was detected incidentally in the main pulmonary artery by routine screening echocardiography. There was no clinical evidence of its presence until a few days after birth. The thrombus grew rapidly, despite administration of heparin. Six days after birth, the patient became cyanotic and had developed right ventricular pressure overload as a result of obstruction of the left pulmonary artery. The thrombus was immediately removed and the DAA resected. The patient was discharged home without any complications. Complications related to thrombus of a DAA can be critical and therefore require careful monitoring. Learning objective: A thrombus extending from a ductus arteriosus aneurysm into the pulmonary artery can have serious consequences; thus, careful monitoring is required. Any signs of such complications should prompt immediate consideration of removal of the aneurysm and thrombus.

Rhythm-control strategy with oral cilostazol for refractory protein-losing enteropathy and sinus node dysfunction after the Fontan operation: A case report.

Despite recent advances in therapeutic approaches, treatment for patients with refractory protein-losing enteropathy (PLE) after undergoing the Fontan procedure remains a challenge for clinicians. In this report, we present a Fontan patient in whom oral cilostazol improved PLE with a restored atrial rhythm. We report on a 13-year-old girl with double-outlet right ventricle, ventricular septal defect, l-transposition of the great arteries, and left ventricle hypoplasia. After the Fontan procedure at 16 months of age, she developed PLE at the age of 2 years. As medical treatments such as diuretics, enalapril, heparin, stent implantation for left pulmonary artery, and oral steroids did not lead to remission, intermittent albumin administration was needed. She had ectopic atrial and junctional rhythms, and cardiac catheterization revealed that the junctional rhythm decreased cardiac output and increased central venous pressure. We therefore started her on cilostazol and succeeded in the maintenance of atrial rhythm, resulting in increased serum albumin, globulin, electrolytes, and nutritional status markers with suppression of bowel inflammation. This patient finally was taken off the steroid and returned to a normal school and home life. Oral cilostazol is a possible therapeutic strategy for refractory PLE, as it improves hemodynamics in Fontan patients with sinus node dysfunction. Learning objective: We present a Fontan patient in whom oral cilostazol for maintaining atrial rhythm improved protein-losing enteropathy (PLE) without any side effects. The junctional rhythm disappeared after the initiation of cilostazol, which suggested that cilostazol stimulated a dominant pacemaker even if the pacemaker was an ectopic focus in the atrium. Oral cilostazol is a possible therapeutic strategy for refractory PLE. We also propose oral cilostazol as a bridging therapy prior to pacemaker implantation.

Efficacy of a Transitional Support Program Among Adolescent Patients With Childhood-Onset Chronic Diseases: A Randomized Controlled Trial.

It is recommended that patients with childhood-onset chronic diseases (CCD) be transferred from pediatric to adult healthcare systems when they reach adulthood. Transitional support helps adolescents with CCD transition smoothly. Transition readiness is one of the key concepts to assess the efficacy of transitional support programs. This study aims to investigate the effect of a transitional support program on transition readiness, self-esteem, and independent consciousness among Japanese adolescents with various CCD using a randomized controlled trial. Adolescents with CCD aged 12-18 years participated in a randomized controlled trial evaluating the efficacy of a transitional support program. The patients in the intervention group visited transitional support outpatient clinics twice. They answered questionnaires regarding their disease and future perspectives to healthcare professionals and independently made a short summary of their disease. All the participants answered the questionnaires four times. Eighty patients participated in this study. Among those in the intervention group, transition readiness within one, three, and 6 months after interventions, and self-esteem within 1 month after interventions were higher than that of the control group. The scores on the "dependence on parents" subscale at 6 months after interventions were lower for the intervention group as compared to the control group. This program is expected to help patients transition smoothly from pediatric to adult healthcare systems.

Medical, welfare, and educational challenges and psychological distress in parents caring for an individual with 22q11.2 deletion syndrome: A cross-sectional survey in Japan.

Parents of children with 22q11.2 deletion syndrome (22q11DS) experience distress not only due to multimorbidity in the patients, but also due to professionals' lack of understanding about 22q11DS and insufficient support systems. This study investigated relationships between medical, welfare, and educational challenges and parental psychological distress. A cross-sectional survey was conducted on primary caregivers of children with 22q11DS. Participants included 125 parents (114 mothers, 91.2%; average age = 44.3 years) who reported their challenges, psychological distress, and child's comorbidities of 22q11DS. Results showed that the difficulty in going to multiple medical institutions (ß = 0.181, p < 0.05) and lack of understanding by welfare staff and insufficient welfare support systems for 22q11DS (ß = 0.220-0.316, all p < 0.05) were associated with parental psychological distress, even after adjusting for child's comorbidities. In the subsample of parents whose child attended an educational institution, inadequate management in classroom and mismatch between service and users in educational settings were associated with psychological distress (ß = 0.222-0.296, all p < 0.05). This study reveals the importance of assessing not only severity of comorbidities in 22q11DS, but also the medical, welfare, and educational challenges for parental mental health.

Poor Myocardial Compaction in a Patient with Recessive MYL2 Myopathy.

Recessive mutations in the Myosin regulatory light chain 2 (MYL2) gene are the cause of an infantile-onset myopathy, associated with fatal myocardial disease of variable macromorphology. We here present the first Japanese family affected with recessive MYL2 myopathy. Affected siblings manifested typical features and the proband's autopsy findings were compatible with the diagnosis of noncompaction cardiomyopathy. The rapidly progressive clinical course of this recessive MYL2 cardiomyopathy highlights the crucial role of c-terminal tails in MYL2 protein in maintaining cardiac morphology and function.

Development and validation of a Japanese version of the TRANSITION-Q.

BACKGROUND: The evaluation of transition readiness is indispensable for long-term follow-ups of adolescent patients with childhood-onset chronic diseases (CCD). We developed a Japanese version of the TRANSITION-Q (TRANSITION-Q-J) and used it to assess Japanese patients with CCD. METHODS: The TRANSITION-Q-J was developed through forward and backward translations followed by cognitive interviews with five adolescent patients. The field test was conducted with 125 adolescent patients, and a retest was conducted with 113 adolescent patients. RESULTS: Confirmatory factor analysis supported the two-factor analysis model including F1 (communication and self-management) and F2 (examination behavior). Sufficient internal consistency and test-retest reliability were demonstrated among the total 14 items, F1, and F2 (Cronbach's α > 0.80, intraclass correlation coefficient > 0.85). Convergent and discriminant validity for the 14 items and F1 were acceptable; however, F2 did not correlate significantly with the Rosenberg Self-Esteem Scale and Independent Consciousness Scale. Regarding known-groups validity, the older group had a significantly higher mean TRANSITION-Q-J score (50.05) than the younger group (43.28; P = 0.04). The same results were found for both F1 and F2. CONCLUSIONS: The TRANSITION-Q-J for adolescent patients with CCD was developed and its reliability and validity were verified. This scale is easy to administer. In addition to being a tool for transition period support, it could be used to verify effective factors and in program outcome evaluation, including intervention studies.

Successful angioplasties using high pressure large balloons in a patient with severe anastomotic pulmonary artery stenosis soon after single-lung transplantation.

A 59-year-old man received a single-lung transplantation due to interstitial pneumonitis. Severe anastomotic pulmonary artery stenosis (PAS) resulting in hypoxia and respiratory symptoms was found in the immediate postoperative period. A scintigraphy showed severe hypoperfusion of the left transplanted lung with 7% of the total pulmonary blood flow. On postoperative days (POD) 29 and 64, the patient underwent serial balloon angioplasties without any complications. Based on the balloon selection criteria for PAS after heart surgery in children, a high-pressure large balloon was used with resultant improvement in respiratory signs and symptoms without any complications. The patient was discharged on POD 92. A follow-up scintigraphy on POD 169 revealed 58% of blood distribution to the left lung. The patient has been doing clinically well and remained asymptomatic one year after the transplantation. Balloon angioplasty with a high-pressure large balloon without stent implantation during an early postoperative period may be a safe and effective strategy. The balloon selecting criteria used in pediatric patients may be applied in the adult lung transplant recipients. .

Biodegradable Extremely-Small-Diameter Vascular Graft Made of Silk Fibroin can be Implanted in Mice.

AIM: Synthetic vascular grafts are widely used in surgical revascularization, mainly for medium- to large-sized vessels. However, synthetic grafts smaller than 6 mm in diameter are associated with a high incidence of thrombosis. In this study, we evaluated silk fibroin, a major protein of silk, with high biocompatibility and biodegradability, as a useful material for extremely-small-diameter vascular grafts. METHODS: A small-sized (0.9 mm inner diameter) graft was braided from a silk fibroin thread. The right carotid arteries of 8- to 14-week-old male C57BL/6 mice were cut at the midpoint, and fibroin grafts (5- to 7-mm in length) were transplanted using a cuff technique with polyimide cuffs. The grafts were harvested at different time points and analyzed histologically. RESULTS: CD31＋ endothelial cells had already started to proliferate at 2 weeks after implantation. At 4 weeks, neointima had formed with α-smooth muscle actin+ cells, and the luminal surface was covered with CD31＋endothelial cells. Mac3＋ macrophages were accumulated in the grafts. Graft patency was confirmed at up to 6 months after implantation. CONCLUSION: This mouse model of arterial graft implantation enables us to analyze the remodeling process and biocompatibility of extremely-small-diameter vascular grafts. Biodegradable silk fibroin might be applicable for further researches using genetically modified mice.

Nurses' perceptions regarding transitional care for adolescents and young adults with childhood-onset chronic diseases.

AIM: Nurses are expected to have a role in the transition of care from pediatric to adult medical practices for adolescents and young adults with childhood-onset chronic diseases. This study compares the experience, knowledge, and perceptions regarding the ideal care among adult unit and pediatric nurses regarding the transition to adult care for those with childhood-onset chronic diseases. METHODS: A cross-sectional study using self-report questionnaires was conducted with nurses in a tertiary hospital in Tokyo. Questions were generated based on a literature review and expert discussion. Data from 1,064 participants were analyzed (adult unit nurses: n = 959, 90.1%; pediatric nurses: n = 105, 9.9%). RESULTS: Among 623 adult unit nurses who had care experience for adult patients with a childhood-onset chronic disease, 458 nurses (73.6%) were unaware of the concept of transitional care. As the obstructive factors for transition, pediatric nurses recognized problems in healthcare providers' attitudes and lack of transitional care coordinators, while the adult unit nurses emphasized the patients' wishes to continue to receive pediatric healthcare. Most adult unit nurses expected pediatric nurses to function as transitional care coordinators. CONCLUSION: Adult unit and pediatric nurses had different perceptions of the barriers in transitioning children with chronic diseases to adult care. It is important to have educational programs focusing on transitional care for all nurses, both to enable pediatric nurses to improve transition readiness of children with chronic diseases and to offer adult patients with a childhood-onset chronic disease continuing support through adult unit nurses.

Noonan syndrome-associated biallelic LZTR1 mutations cause cardiac hypertrophy and vascular malformations in zebrafish.

BACKGROUND: Variants in the LZTR1 (leucine-zipper-like transcription regulator 1) gene (OMIM #600574) have been reported in recessive Noonan syndrome patients. In vivo evidence from animal models to support its causative role is lacking. METHODS: By CRISPR-Cas9 genome editing, we generated lztr1-mutated zebrafish (Danio rerio). Analyses of histopathology and downstream signaling were performed to investigate the pathogenesis of cardiac and extracardiac abnormalities in Noonan syndrome. RESULTS: A frameshift deletion allele was created in the zebrafish lztr1. Crosses of heterozygotes obtained homozygous lztr1 null mutants that modeled LZTR1 loss-of-function. Histological analyses of the model revealed ventricular hypertrophy, the deleterious signature of Noonan syndrome-associated cardiomyopathy. Further, assessment for extracardiac abnormalities documented multiple vascular malformations, resembling human vascular pathology caused by RAS/MAPK activation. Due to spatiotemporal regulation of LZTR1, its downstream function was not fully elucidated from western blots of adult tissue. CONCLUSION: Our novel zebrafish model phenocopied human recessive Noonan syndrome and supported the loss-of-function mechanism of disease-causing LZTR1 variants. The discovery of vascular malformations in mutants calls for the clinical follow-up of patients to monitor for its emergence. The model will serve as a novel platform for investigating the pathophysiology linking RAS/MAPK signaling to cardiac and vascular pathology.

Nonosmotic secretion of arginine vasopressin and salt loss in hyponatremia in Kawasaki disease.

BACKGROUND: The precise mechanism of hyponatremia in Kawasaki disease (KD) remains elusive because assessment of volume status based on serial changes in body weight is lacking in previous reports. METHODS: Seventeen patients who were diagnosed with KD and hyponatremia (serum sodium levels <135 mmol/L) were analyzed. Volume status was assessed based on serial changes in body weight. Plasma arginine vasopressin (ADH), urine electrolytes, and serum cytokine levels were measured on diagnosis of hyponatremia. An increase in body weight by >3% was defined as hypervolemia and a decrease in body weight by >3% was defined as hypovolemia. RESULTS: The volume status was hypervolemic in three patients (18%), euvolemic in 14 (82%), and hypovolemic in none (0%). Five (29%) patients were diagnosed with "syndrome of inappropriate secretion of antidiuretic hormone" (SIADH) and no patients were diagnosed with hypotonic dehydration. The contribution of decreased total exchangeable cations (salt loss) to hyponatremia (5.9% [interquartile range, 4.3%, 6.7%]) was significantly larger than that of increased total body water (-0.7% [-1.8%, 3.1%]) (P = 0.004). Serum interleukin-6 levels were elevated in all of the nine patients who were evaluated. Among the 12 (71%) patients who did not meet the criteria of SIADH and hypotonic dehydration, plasma ADH levels were inappropriately high in ten patients. These patients were also characterized by euvolemic or hypervolemic hyponatremia and salt loss, which might be compatible with a diagnosis of SIADH. CONCLUSIONS: Our study shows that hyponatremia in KD is euvolemic or hypervolemic and is associated with nonosmotic secretion of ADH and salt loss in the majority of patients.