Hypertrophic cardiomyopathy in neonates with congenital hyperinsulinism

Unique Aspects of Hypertrophic Cardiomyopathy in Children

Hypertrophic cardiomyopathy (HCM) is a primary heart muscle disease characterized by left ventricular hypertrophy that can be asymptomatic or with presentations that vary from left ventricular outflow tract obstruction, heart failure from diastolic dysfunction, arrhythmias, and/or sudden cardiac death. Children younger than 1 year of age tend to have worse outcomes and often have HCM secondary to inborn errors of metabolism or syndromes such as RASopathies. For children who survive or are diagnosed after 1 year of age, HCM outcomes are often favourable and similar to those seen in adults. This is because of sudden cardiac death risk stratification and medical and surgical innovations. Genetic testing and timely cardiac screening are paving the way for disease-modifying treatment as gene-specific therapies are being developed.

Cardiac Hypertrophy Associated with Insulin Therapy in Extremely Preterm Infants

BACKGROUND

In the neonatal period, cardiac hypertrophy (CH) has been commonly associated with hyperinsulinemic pathologies, and the first case of CH in an extremely preterm infant treated with insulin infusion has recently been reported. To confirm this association, we report a case series of patients who developed CH after insulin therapy.

METHODS

Infants with gestational age < 30 weeks and birth weight < 1500 g, born from November 2017 to June 2022, were studied if they developed hyperglycemia requiring treatment with insulin and had echocardiographic diagnosis of CH.

RESULTS

We studied 10 extremely preterm infants (24.3 ± 1.4 weeks) who developed CH at a mean age of 124 ± 37 h of life, 98 ± 24 h after the initiation of insulin therapy. All surviving patients had resolution of CH at discharge, while three of four (75%) of the deceased patients had persistent CH.

CONCLUSIONS

Our case series supports the association between the development of CH and insulin therapy in extremely preterm infants and suggests further caution and the need for echocardiographic monitoring when treating these fragile patients with insulin.

Donohue syndrome in an Egyptian infant: a case report

Objectives

We aim to report a case of Donohue syndrome (DS) which is a rare genetically encoded, autosomal inherited recessive disorder linked with severe insulin-resistant diabetes.

Case presentation

We hereby report a case of a 4 month -old girl infant with DS. The patient exhibited dysmorphic facial features, severe growth retardation, fasting hypoglycemia, postprandial hyperglycemia, and hyperinsulinemia which are the hallmarks of DS. The diagnosis of DS was confirmed by genetic analysis. The patient was treated with high-dose insulin and frequent nasogastric formula milk feeding to achieve reasonable glycemic control.

Conclusions

We reported a typical case of DS in a 4-month-old female infant characterized by peculiar dysmorphic features and failure to thrive. She also fulfilled the biochemical criteria of fasting hypoglycemia, postprandial hyperglycemia, and severe hyperinsulinemia. The diagnosis was confirmed by a molecular genetic study. Our patient achieved reasonable glycemic control after treatment with high-dose insulin.

Effect of hyperglycemia on tbx5a and nppa gene expression and its correlation to structural and functional changes in developing zebrafish heart

The objective of the current study is to analyze the effects of gestational diabetes on structural and functional changes in correlation with these two essential regulators of developing hearts in vivo using zebrafish embryos. We employed fertilized zebrafish embryos exposed to a hyperglycemic condition of 25 mM glucose for 96 h postfertilization. The embryos were subjected to various structural and functional analyses in a time-course manner. The data showed that exposure to high glucose significantly affected the embryo's size, heart length, heart rate, and looping of the heart compared to the control. Further, we observed an increased incidence of ventricular standstill and valvular regurgitation with a marked reduction of peripheral blood flow in the high glucose-exposed group compared to the control. In addition, the histological data showed that the high-glucose exposure markedly reduced the thickness of the wall and the number of cardiomyocytes in both atrium and ventricles. We also observed striking alterations in the pericardium like edema, increase in diameter with thinning of the wall compared to the control group. Interestingly, the expression of tbx5a and nppa was increased in the early development and found to be repressed in the later stage of development in the hyperglycemic group compared to the control. In conclusion, the developing heart is more susceptible to hyperglycemia in the womb, thereby showing various developmental defects possibly by altering the expression of crucial gene regulators such as tbx5a and nppa.

Programming of cardiometabolic health: the role of maternal and fetal hyperinsulinaemia

Obesity and gestational diabetes during pregnancy have multiple short- and long-term consequences for both mother and child. One common feature of pregnancies complicated by maternal obesity and gestational diabetes is maternal hyperinsulinaemia, which has effects on the mother and her adaptation to pregnancy. Even though insulin does not cross the placenta insulin can act on the placenta as well affecting placental growth, angiogenesis and lipid metabolism. Obese and gestational diabetic pregnancies are often characterised by maternal hyperglycaemia resulting in exposure of the fetus to high levels of glucose, which freely crosses the placenta. This leads to stimulation of fetal ß-cells and insulin secretion in the fetus. Fetal hyperglycaemia/hyperinsulinaemia has been shown to cause multiple complications in fetal development, such as altered growth trajectories, impaired neuronal and cardiac development and early exhaustion of the pancreas. These changes could increase the susceptibility of the offspring to develop cardiometabolic diseases later in life. In this review, we aim to summarize and review the mechanisms by which maternal and fetal hyperinsulinaemia impact on (i) maternal health during pregnancy; (ii) placental and fetal development; (iii) offspring energy homeostasis and long-term cardiometabolic health; (iv) how interventions can alleviate these effects.

Cardiac hypertrophy and insulin therapy in a pre-term newborn: is there a relationship?

Background

Hypertrophic cardiomyopathy (HCM) in newborns is a rare condition with heterogeneous etiologies. While the relationship between hyperinsulinism and cardiac hypertrophy (CH) is known, hyperinsulinism has not been reported as cause of HCM.

Case presentation

We report the case of cardiac hypertrophy (CH) in an Extremely Low Birth Weight (ELBW) infant; this patient underwent insulin therapy after the onset of persistent hyperglycemia due to parenteral nutrition (PN), supporting the hypothesis of a role of iatrogenic hyperinsulinemia in the development of HCM.

Conclusions

The present case underlines the importance of a close cardiological follow-up in infants undergoing insulin infusion for an alteration in the glucose metabolism.

Premature closure of ductus arteriosus after a single dose of diclofenac during pregnancy

A male term neonate was admitted to the neonatal intensive care unit in the first hours of life with central cyanosis. Echocardiogram showed severe biventricular hypertrophy, markedly right-sided, tricuspid regurgitation, a patent foramen ovale and a closed ductus arteriosus (CDA). The mother recalled being treated with a single dose of intravenous diclofenac for low back pain 2 weeks earlier. The newborn was started on propranolol with symptomatic improvement and was discharged on day 10. At 1-month follow-up, he showed complete resolution of ventricular hypertrophy and suspended propranolol. In the literature, of the 22 cases of CDA after intrauterine exposure to diclofenac, 11 resolved in utero, 3 required ventilatory and inotropic support and 1 evolved to persistent pulmonary hypertension. In this case, a thorough anamnesis was key to identify the probable cause of an otherwise unexplained transient ventricular hypertrophy. This case also alerts to the fetal risks of non-steroidal anti-inflammatory drugs during the third trimester, requiring close monitoring.

Hypertrophic Cardiomyopathy in Infants from the Perspective of Cardiomyocyte Maturation

Hypertrophic cardiomyopathy (HCM) in infancy is rare and many fulminant cases are fatal. Infantile HCM shows a rapid progressive clinical course and different characteristics compared with late-onset HCM presenting during the prepubertal age. There are also spontaneously resolving phenotypes of HCM that are diagnosed in neonates being treated for bronchopulmonary dysplasia with corticosteroids or in those with other problems related to maternal endocrine diseases. The pathophysiology of infantile HCM has not been well described. Therefore, this review updates the pathophysiology of infantile HCM and includes molecular studies on maturation of cardiomyocytes from a clinician's point of view.

Hypertrophic cardiomyopathy (HCM) is characterized by ventricular wall hypertrophy with diastolic dysfunction. Pediatric HCM is distinguished from the adult in many aspects. Most children with HCM do not present clinically until the adolescent period, even when they are born with genetic mutations. Some infants with early-onset HCM present with massive progressive myocardial hypertrophy in the first few months of life, which is often fatal. The mortality of pediatric HCM peaks during the infantile and adolescent periods. These periods roughly correlate with children's growth spurt. Non-sarcomeric causes of HCM are more frequent in pediatric HCM, while sarcomeric causes are more common in adults. From the perspective of cardiac development, the fetal heart has immature cardiomyocytes, which are characterized by proliferation and exit their cell cycles with a decreased regenerative property after birth. In the perinatal period, there is a dynamic change in maturation of cardiomyocytes from immature to mature cells. Infants who are treated with steroids or born to mothers with diabetes or hyperthyroidism often show phenotypes of HCM, which gradually resolve. With remarkable advancement of molecular biology, understanding on maturation of cardiomyocytes has increased. Neonates undergo abrupt environmental changes during the transitional circulation, which is affected by oxygen, metabolic and hormonal fluctuations. Derangement in physiological transition to the normal postnatal environment may influence maturation of proliferative immature cardiomyocytes during early infancy. This article reviews updates of infantile HCM and recent molecular studies related to maturation of cardiomyocytes from the clinical point of view of identifying distinct characteristics of infantile HCM.

Nutritional and developmental programming effects of insulin

The discovery of insulin in 1921 was a major breakthrough in medicine and for therapy in patients with diabetes. The dramatic rise in the prevalence of overweight and obesity has been tightly linked to an increased prevalence of gestational diabetes mellitus (GDM), which poses major health concerns. Babies born to GDM mothers are more likely to develop obesity, type 2 diabetes and cardiovascular disease later in life. Evidence accumulated during the past two decades has revealed that high levels insulin, such as those observed during GDM, can have a widespread effect on the development and function of a variety of organs. This review summarises our current knowledge on the role of insulin in the placenta, cardiovascular system and brain during critical periods of development, as well as how it can contribute to lifelong metabolic regulation. We also discuss possible intervention strategies to ameliorate and hopefully reverse the developmental defects associated with obesity and GDM.

Could the E/A ratio be included in the cardiological evaluation of the offspring of diabetic mothers? A case-control study in South Sardinia

INTRODUCTION

Diabetes mellitus (DM) is a chronic disease widespread in the world. Sardinia represents, together with Finland, the region with the highest incidence of type 1 DM (DM1), as well as a high prevalence of gestational DM (GDM). Despite the improvement in obstetric surveillance, perinatal and long-term adverse outcomes are still frequent in the offspring of diabetic mothers. During gestations complicated by DM, fetal heart is one of the most affected organ potentially undergoing structural heart defects or several degrees of fetal myocardium hypertrophy and impaired cardiac function.

AIM

The aim of our study was to evaluate, through echocardiographic examination, cardiac features and performance in a South Sardinian population of newborns of diabetic mothers comparing them to a group of control subjects.

CONCLUSIONS

In our sample, the E/A ratio resulted a significant marker of early diastolic dysfunction in asymptomatic neonates born by diabetic mothers, even if such result should be confirmed on larger samples.

Role of fetal echocardiography in morphologic and functional assessment of fetal heart in diabetic mothers

Background

Diabetes mellitus (DM) is the commonest medical disorder faced during pregnancy and it includes type I, type II, and gestational diabetes. It may predispose to various complications including fetus malformation, macrosomia, spontaneous abortion, stillbirth, neonatal death, and intrauterine growth retardation. Hypertrophic cardiomyopathy (HCM) is one of the common anomalies depicted with diabetes. Fetal cardiac function analysis might provide important information on the hemodynamic status and cardiac adaptation to different perinatal complications.

Results

The mean septal thickness in the diabetic group was 0.7163 ± 0.1746 cm and 0.4989 ± 0.08068 cm in the control group. The mean myocardial thickness of the right ventricular free wall in the diabetic group was 0.6532 ± 0.13792 cm and 0.4874 ± 0.07482 cm in the control group. The mean myocardial thickness of the left ventricular free wall in the diabetic group was 0.6437 ± 0.13421 cm and 0.4737 ± 0.07573 cm in the control group. The mean value of myocardial performance index (Tie Index) in the diabetic group was 0.6232 ± 0.15606 and 0.4626 ± 0.04357 in the control group.

Conclusion

From our study, we can conclude that prenatal complete echocardiographic study should be mandatory in fetuses of diabetic mothers due to high risk of congenital heart defects and onset of hypertrophic cardiomyopathy with fetal cardiac function impairment in the third trimester.

Early diagnosis of congenital heart defects as well as evidence of hypertrophic cardiomyopathy and fetal cardiac function impairment that occurs in fetuses of maternal diabetes will definitely guide prompt postnatal therapy and care for those neonates.

The difficult management of persistent, non-focal congenital hyperinsulinism: A retrospective review from a single, tertiary center

BACKGROUND/OBJECTIVE

Congenital hyperinsulinism (CHI) is a rare, heterogeneous disease with transient or persistent hypoglycemia. Histologically, focal, diffuse, and atypical forms of CHI exist, and at least 11 disease-causing genes have been identified.

METHODS

We retrospectively evaluated the treatment and outcome of a cohort of 40 patients with non-focal, persistent CHI admitted to the International Hyperinsulinism Center, Denmark, from January 2000 to May 2017.

RESULTS

Twenty-two patients (55%) could not be managed with medical monotherapy (diazoxide or octreotide) and six (15%) patients developed severe potential side effects to medication. Surgery was performed in 17 (43%) patients with resection of 66% to 98% of the pancreas. Surgically treated patients had more frequently K_ATP -channel gene mutations (surgical treatment 12/17 vs conservative treatment 6/23, P = .013), highly severe disease (15/17 vs 13/23, P = .025) and clinical onset <30 days of age (15/17 vs 10/23, P = .004). At last follow-up at median 5.3 (range: 0.3-31.3) years of age, 31/40 (78%) patients still received medical treatment, including 12/17 (71%) after surgery. One patient developed diabetes after a 98% pancreatic resection. Problematic treatment status was seen in 7/40 (18%). Only 8 (20%) had clinical remission (three spontaneous, five after pancreatic surgery). Neurodevelopmental impairment (n = 12, 30%) was marginally associated with disease severity (P = .059).

CONCLUSIONS

Persistent, non-focal CHI remains difficult to manage. Neurological impairment in 30% suggests a frequent failure of prompt and adequate treatment. A high rate of problematic treatment status at follow-up demonstrates an urgent need for new medical treatment modalities.

Neonatal cardiac hypertrophy: the role of hyperinsulinism-a review of literature

Hypertrophic cardiomyopathy (HCM) in neonates is a rare and heterogeneous disorder which is characterized by hypertrophy of heart with histological and functional disruption of the myocardial structure/composition. The prognosis of HCM depends on the underlying diagnosis. In this review, we emphasize the importance to consider hyperinsulinism in the differential diagnosis of HCM, as hyperinsulinism is widely associated with cardiac hypertrophy (CH) which cannot be distinguished from HCM on echocardiographic examination. We supply an overview of the incidence and treatment strategies of neonatal CH in a broad spectrum of hyperinsulinemic diseases. Reviewing the literature, we found that CH is reported in 13 to 44% of infants of diabetic mothers, in approximately 40% of infants with congenital hyperinsulinism, in 61% of infants with leprechaunism and in 48 to 61% of the patients with congenital generalized lipodystrophy. The correct diagnosis is of importance since there is a large variation in prognoses and there are various strategies to treat CH in hyperinsulinemic diseases.Conclusion: The relationship between CH and hyperinsulism has implications for clinical practice as it might help to establish the correct diagnosis in neonates with cardiac hypertrophy which has both prognostic and therapeutic consequences. In addition, CH should be recognized as a potential comorbidity which might necessitate treatment in all neonates with known hyperinsulinism.What is Known:• Hyperinsulinism is currently not acknowledged as a cause of hypertrophic cardiomyopathy (HCM) in textbooks and recent Pediatric Cardiomyopathy Registry publications.What is New:• This article presents an overview of the literature of hyperinsulinism in neonates and infants showing that hyperinsulinism is associated with cardiac hypertrophy (CH) in a broad range of hyperinsulinemic diseases.• As CH cannot be distinguished from HCM on echocardiographic examination, we emphasize the importance to consider hyperinsulinism in the differential diagnosis of HCM/CH as establishing the correct diagnosis has both prognostic and therapeutic consequences.

Clinical characteristics and phenotype-genotype review of 25 Omani children with congenital hyperinsulinism in infancy. A one-decade single-center experience

Objectives:

To report the genotype-phenotype characteristics, demographic features and clinical outcome of Omani patients with congenital hyperinsulinism (CHI).

Methods:

We retrospectively analyzed the clinical, biochemical, genotypical, phenotypical characteristics and outcomes of children with CHI who were presented to the pediatric endocrine team in the Royal Hospital, Muscat, Oman between January 2007 and December 2016.

Results:

Analysis of 25 patients with CHI genetically revealed homozygous mutation in ABCC8 in 23 (92%) patients and 2 patients (8%) with compound heterozygous mutation in ABCC8. Fifteen (60%) patients underwent subtotal pancreatectomy as medical therapy failed and 2 (8%) patients showed response to medical therapy. Three patients expired during the neonatal period, 2 had cardiomyopathy and sepsis, and one had sepsis and severe metabolic acidosis. Out of the 15 patients who underwent pancreatectomy, 6 developed diabetes mellitus, 6 continued to have hypoglycemia and required medical therapy and one had pancreatic exocrine dysfunction post-pancreatectomy, following up with gastroenterology clinic and was placed on pancreatic enzyme supplements, while 2 patients continued to have hypoglycemia and both had abdominal MRI and 18-F-fluoro-L-DOPA positron emission tomography scan (PET-scan), that showed persistent of the disease and started on medical therapy.

Conclusion:

Mutation in ABCC8 is the most common cause of CHI and reflects the early age of presentation. There is a need for early diagnosis and appropriate therapeutic strategy.

Cardiomyopathy in Children: Classification and Diagnosis: A Scientific Statement From the American Heart Association

In this scientific statement from the American Heart Association, experts in the field of cardiomyopathy (heart muscle disease) in children address 2 issues: the most current understanding of the causes of cardiomyopathy in children and the optimal approaches to diagnosis cardiomyopathy in children. Cardiomyopathies result in some of the worst pediatric cardiology outcomes; nearly 40% of children who present with symptomatic cardiomyopathy undergo a heart transplantation or die within the first 2 years after diagnosis. The percentage of children with cardiomyopathy who underwent a heart transplantation has not declined over the past 10 years, and cardiomyopathy remains the leading cause of transplantation for children >1 year of age. Studies from the National Heart, Lung, and Blood Institute-funded Pediatric Cardiomyopathy Registry have shown that causes are established in very few children with cardiomyopathy, yet genetic causes are likely to be present in most. The incidence of pediatric cardiomyopathy is ≈1 per 100 000 children. This is comparable to the incidence of such childhood cancers as lymphoma, Wilms tumor, and neuroblastoma. However, the published research and scientific conferences focused on pediatric cardiomyopathy are sparcer than for those cancers. The aim of the statement is to focus on the diagnosis and classification of cardiomyopathy. We anticipate that this report will help shape the future research priorities in this set of diseases to achieve earlier diagnosis, improved clinical outcomes, and better quality of life for these children and their families.

Embryonic programming of heart disease in response to obesity during pregnancy

Obesity during pregnancy programs adult-onset heart disease in the offspring. Clinical studies indicate that exposure to an adverse environment in utero during early, as compared to late, gestation leads to a higher prevalence of adult-onset heart disease. This suggests that the early developing heart is particularly sensitive to an adverse environment. Accordingly, growing evidence from clinical studies and animal models demonstrates that obesity during pregnancy alters the function of the fetal heart, programming a higher risk of cardiovascular disease later in life. Moreover, gene expression patterns and signaling pathways that promote initiation and progression of cardiovascular disease are altered in the hearts in offspring born to obese mothers. However, the mechanisms mediating the long-term effects of an adverse environment in utero on the developing heart leading to adult-onset disease are not clear. Here, we review clinical and experimental evidence documenting the effects of maternal obesity during pregnancy on the fetal and post-natal heart and emphasize on the potential mechanisms of disease programming.

Diagnosis and management of hyperinsulinaemic hypoglycaemia

Hyperinsulinaemic hypoglycaemia (HH) is a heterogeneous condition with dysregulated insulin secretion which persists in the presence of low blood glucose levels. It is the most common cause of severe and persistent hypoglycaemia in neonates and children. Recent advances in genetics have linked congenital HH to mutations in 14 different genes that play a key role in regulating insulin secretion (ABCC8, KCNJ11, GLUD1, GCK, HADH, SLC16A1, UCP2, HNF4A, HNF1A, HK1, PGM1, PPM2, CACNA1D, FOXA2). Histologically, congenital HH can be divided into 3 types: diffuse, focal and atypical. Due to the biochemical basis of this condition, it is essential to diagnose and treat HH promptly in order to avoid the irreversible hypoglycaemic brain damage. Recent advances in the field of HH include new rapid molecular genetic testing, novel imaging methods (18F-DOPA PET/CT), novel medical therapy (long-acting octreotide formulations, mTOR inhibitors, GLP-1 receptor antagonists) and surgical approach (laparoscopic surgery). The review article summarizes the current diagnostic methods and management strategies for HH in children.

Prenatal programming: adverse cardiac programming by gestational testosterone excess

Adverse events during the prenatal and early postnatal period of life are associated with development of cardiovascular disease in adulthood. Prenatal exposure to excess testosterone (T) in sheep induces adverse reproductive and metabolic programming leading to polycystic ovarian syndrome, insulin resistance and hypertension in the female offspring. We hypothesized that prenatal T excess disrupts insulin signaling in the cardiac left ventricle leading to adverse cardiac programming. Left ventricular tissues were obtained from 2-year-old female sheep treated prenatally with T or oil (control) from days 30-90 of gestation. Molecular markers of insulin signaling and cardiac hypertrophy were analyzed. Prenatal T excess increased the gene expression of molecular markers involved in insulin signaling and those associated with cardiac hypertrophy and stress including insulin receptor substrate-1 (IRS-1), phosphatidyl inositol-3 kinase (PI3K), Mammalian target of rapamycin complex 1 (mTORC1), nuclear factor of activated T cells -c3 (NFATc3), and brain natriuretic peptide (BNP) compared to controls. Furthermore, prenatal T excess increased the phosphorylation of PI3K, AKT and mTOR. Myocardial disarray (multifocal) and increase in cardiomyocyte diameter was evident on histological investigation in T-treated females. These findings support adverse left ventricular remodeling by prenatal T excess.

Image-Derived Assessment of Left Ventricular Mass in Fetal Myocardial Hypertrophy by 4-Dimensional Echocardiography: An In Vitro Study

OBJECTIVES

This study tested the accuracy of new 4-dimensional fetal echocardiography to evaluate left ventricular (LV) mass in an experimental model of fetal myocardial hypertrophy.

METHODS

Ten fresh rabbit hearts were studied. Fetal myocardial hypertrophy was simulated by fixing different amounts of myocardial tissue to the LV epicardium. A small latex balloon was mounted on vinyl tubing and fixed within each LV cavity. The proximal end of the tube was attached to a pulsatile pump apparatus. The pump was calibrated to deliver stroke volumes of 2 and 4 mL at stroke rates of 60 and 120 beats per minute (bpm). Four-dimensional data were acquired and analyzed with quantification software. Reference values for LV mass were determined by the displacement method.

RESULTS

Echo-derived measurements of LV mass showed good correlations with reference values at all stroke rates and stroke volumes: at 2 mL and 60 bpm, r = 0.95; at 2 mL and 120 bpm, r = 0.95; at 4 mL and 60 bpm, r = 0.93; and at 4 mL and 120 bpm, r = 0.95 (P< .01 for all values). There was also excellent interobserver (r = 0.98; mean difference of -0.32 g; -4.4% of the mean) and intraobserver (r = 0.98; mean difference of -0.28 g; -3.8% of the mean) agreement.

CONCLUSIONS

In this controlled in vitro study, high-resolution 4-dimensional echocardiography was shown to accurately assess LV mass and have the potential to evaluate fetal myocardial hypertrophy.

Perspective on the Genetics and Diagnosis of Congenital Hyperinsulinism Disorders

CONTEXT

Congenital hyperinsulinism (HI) is the most common cause of hypoglycemia in children. The risk of permanent brain injury in infants with HI continues to be as high as 25-50% due to delays in diagnosis and inadequate treatment. Congenital HI has been described since the birth of the JCEM under various terms, including "idiopathic hypoglycemia of infancy," "leucine-sensitive hypoglycemia," or "nesidioblastosis."

EVIDENCE ACQUISITION

In the past 20 years, it has become apparent that HI is caused by genetic defects in the pathways that regulate pancreatic β-cell insulin secretion.

EVIDENCE SYNTHESIS

There are now 11 genes associated with monogenic forms of HI (ABCC8, KCNJ11, GLUD1, GCK, HADH1, UCP2, MCT1, HNF4A, HNF1A, HK1, PGM1), as well as several syndromic genetic forms of HI (eg, Beckwith-Wiedemann, Kabuki, and Turner syndromes). HI is also the cause of hypoglycemia in transitional neonatal hypoglycemia and in persistent hypoglycemia in various groups of high-risk neonates (such as birth asphyxia, small for gestational age birthweight, infant of diabetic mother). Management of HI is one of the most difficult problems faced by pediatric endocrinologists and frequently requires difficult choices, such as near-total pancreatectomy and/or highly intensive care with continuous tube feedings. For 50 years, diazoxide, a KATP channel agonist, has been the primary drug for infants with HI; however, it is ineffective in most cases with mutations of ABCC8 or KCNJ11, which constitute the majority of infants with monogenic HI.

CONCLUSIONS

Genetic mutation testing has become standard of care for infants with HI and has proven to be useful not only in projecting prognosis and family counseling, but also in diagnosing infants with surgically curable focal HI lesions. (18)F-fluoro-L-dihydroxyphenylalanine ((18)F-DOPA) PET scans have been found to be highly accurate for localizing such focal lesions preoperatively. New drugs under investigation provide hope for improving the outcomes of children with HI.

Long-term medical treatment in congenital hyperinsulinism: a descriptive analysis in a large cohort of patients from different clinical centers

BACKGROUND

Up to now, only limited data on long-term medical treatment in congenital hyperinsulinism (CHI) is available. Moreover, most of the drugs used in CHI are therefore not approved. We aimed to assemble more objective information on medical treatment in CHI with regard to type and duration, dosage as well as side effects.

METHODS

We searched MEDLINE (from 1947) and EMBASE (from 1988) using the OVID interface for relevant data to evaluate medical treatment in a large cohort of patients with CHI from different clinical centers. Randomized, controlled trials were not available. We evaluated case reports and case series. No language restrictions were made.

RESULTS

A total number of 619 patients were medically treated and information regarding conservative treatment was available. Drugs used were diazoxide (in 84% of patients), somatostatin analogues (16%), calcium channel antagonists (4%) and glucagon (1%). Mean dose of diazoxide was 12.5 (±4.3) mg/kg ⋅ d (range 2-60 mg/kg ⋅ d), mean duration of diazoxide treatment until remission was 57 months. Side effects of diazoxide were usually not severe. The causal relation between diazoxide and severe side effects, e.g. heart failure (3.7%) remains doubtful. Mean dose of octreotide was 14.9 (±7.5) μg/kg ⋅ d (range 2.3-50 μg/kg ⋅ d), of lanreotide 67.3 (±39.8) mg ⋅ month (range 10-120 mg ⋅ month). Mean duration of treatment with somatostatin analogues until remission was 49 months. Frequent side effects included tachyphylaxis and mild gastrointestinal symptoms. The risk of persistent growth deceleration was low (<5%).

CONCLUSIONS

Severe side effects are rare and a causal relation remains disputable. We conclude that long-term conservative treatment of CHI is feasible.

Fatal congenital hypertrophic cardiomyopathy and a pancreatic nodule morphologically identical to focal lesion of congenital hyperinsulinism in an infant with costello syndrome: case report and review of the literature

Costello syndrome is characterized by constitutional mutations in the proto-oncogene HRAS, causing dysmorphic features, multiple cardiac problems, intellectual disability, and an increased risk of neoplasia. We report a male infant with dysmorphic features, born prematurely at 32 weeks, who, during his 3-month life span, had an unusually severe and ultimately fatal manifestation of hypertrophic cardiomyopathy and hyperinsulinemic hypoglycemia. Molecular studies in this patient demonstrated the uncommon Q22K mutation in the HRAS gene, diagnostic of Costello syndrome. The major autopsy findings revealed hypertrophic cardiomyopathy, congenital myopathy, and a 1.4-cm pancreatic nodule that was positive for insulin expression and morphologically identical to a focal lesion of congenital hyperinsulinism. Sequencing of KCNJ11 and ABCC8, the 2 most commonly mutated genes in focal lesion of congenital hyperinsulinism, revealed no mutations. While hyperinsulinism is a recognized feature of RASopathies, a focal proliferation of endocrine cells similar to a focal lesion of hyperinsulinism is a novel pathologic finding in Costello syndrome.

Liver injury may increase the risk of diazoxide toxicity: a case report

Stress-related hyperinsulinism (HI) may lead to recalcitrant hypoglycemia for weeks or months following perinatal stress, often in premature newborn infants. Diazoxide is an effective and usually safe medication to treat this type and other types of neonatal HI. We report a male infant born at 35-week gestation with severe respiratory distress who developed prolonged hypoglycemia requiring high glucose infusion rates. He also had abnormal liver function tests, including hypoalbuminemia. Laboratory tests were consistent with HI, which responded to diazoxide treatment (10 mg/kg/day started at 10 days of age). The patient developed cardiorespiratory failure, hepatomegaly, worsening liver function tests, and hyperglycemia 7 weeks after the initiation of therapy. Diazoxide was discontinued with rapid resolution of the cardiorespiratory failure and without recurrence of hypoglycemia.

CONCLUSION

We hypothesize that low albumin level may increase the toxicity of diazoxide, possibly by increasing the free diazoxide concentration, as this compound is typically >90% bound to plasma proteins.

WHAT IS KNOWN

Diazoxide binds to plasma proteins >90% and excreted in urine. Dose adjustment is recommended in patients with impaired kidney functions. What is New: Literature is not available regarding diazoxide dose adjustment in patients with liver injury. Diazoxide toxicity is not dose-dependent.

Maternal Hyperglycemia Directly and Rapidly Induces Cardiac Septal Overgrowth in Fetal Rats

Cardiac septal overgrowth complicates 10-40% of births from diabetic mothers, but perplexingly hyperglycemia markers during pregnancy are not reliably predictive. We thus tested whether fetal exposure to hyperglycemia is sufficient to induce fetal cardiac septal overgrowth even in the absence of systemic maternal diabetes. To isolate the effects of hyperglycemia, we infused glucose into the blood supply of the left but not right uterine horn in nondiabetic pregnant rats starting on gestational day 19. After 24 h infusion, right-sided fetuses and dams remained euglycemic while left-sided fetuses were moderately hyperglycemic. Echocardiograms in utero demonstrated a thickened cardiac septum among left-sided (glucose-exposed, 0.592 ± 0.016 mm) compared to right-sided (control, 0.482 ± 0.016 mm) fetuses. Myocardial proliferation was increased 1.5 ± 0.2-fold among left-sided compared to right-sided fetuses. Transcriptional markers of glucose-derived anabolism were not different between sides. However, left-sided fetuses exhibited higher serum insulin and greater JNK phosphorylation compared to controls. These results show that hyperglycemic exposure is sufficient to rapidly induce septal overgrowth even in the absence of the myriad other factors of maternal diabetes. This suggests that even transient spikes in glucose may incite cardiac overgrowth, perhaps explaining the poor clinical correlation of septal hypertrophy with chronic hyperglycemia.

Percutaneous left main coronary artery stent for acute myocardial ischemia after repaired ALCAPA

Percutaneous coronary artery stent angioplasty is rare in the pediatric population but can be a life-saving by rapidly reestablishing flow to an obstructed coronary artery. It is a technically challenging and high-risk procedure in infants and further limited by the need for future surgical intervention. We report of an infant with anomalous left coronary artery from the pulmonary artery who underwent acutely successful surgical reimplantation of the left coronary artery onto the ascending aorta. One month later, she developed acute myocardial ischemia and emergent catheterization diagnosed near-total occlusion of the left coronary artery. We implanted a 2.5 mm coronary stent in the left main coronary artery with reestablishment of flow. The patient's left ventricular systolic function recovered within 4 weeks and repeat angiography 3 months later showed complete normalization of the entire left coronary artery system. The patient weighed 3 kg and was < 6 weeks of age at the time of stent implantation which to our knowledge is the smallest and youngest reported patient to undergo coronary stent angioplasty. This case supports the feasibility of this procedure in infants as a temporizing solution to hemodynamic instability from myocardial ischemia due to coronary artery stenosis. The left ventricular systolic function remained normal at 7 months after stent placement and the patient was clinically well from a cardiac perspective.

Update on neonatal hypoglycemia

PURPOSE OF REVIEW

Neonatal hypoglycemia is one of the most common biochemical abnormalities encountered in the newborn. However, controversy remains surrounding its definition and management especially in asymptomatic patients.

RECENT FINDINGS

New information has been published that describes the incidence and timing of low glucose concentrations in the groups most at risk for asymptomatic neonatal hypoglycemia. Furthermore, one large prospective study failed to find an association between repetitive low glucose concentrations and poor neurodevelopmental outcomes in preterm infants. But hypoglycemia due to hyperinsulinism, especially genetic causes, continued to be associated with brain injury. New advances were made in the diagnosis and management of hyperinsulinism, including acquired hyperinsulinism in small for gestational age infants and others. Continuous glucose monitoring remains an attractive strategy for future research in this area.

SUMMARY

The fundamental question of how best to manage asymptomatic newborns with low glucose concentrations remains unanswered. Balancing the risks of overtreating newborns with low glucose concentrations who are undergoing a normal transition following birth against the risks of undertreating those in whom low glucose concentrations are pathological, dangerous, and/or a harbinger of serious metabolic disease remains a challenge.

The evolving course of HNF4A hyperinsulinaemic hypoglycaemia--a case series

BACKGROUND

Hepatocyte nuclear factor 4 alpha (HNF4A) gene mutations have a well-recognized role in maturity-onset diabetes of the young and have recently been described in congenital hyperinsulinism. A biphasic phenotype has been postulated, with macrosomia and congenital hyperinsulinism in infancy, and diabetes in young adulthood. In this case series, we report three children with HNF4A mutations (two de novo) and diazoxide-responsive congenital hyperinsulinism, highlighting the potential for ongoing diazoxide requirement and the importance of screening for these mutations even in the absence of family history.

CASE REPORTS

All patients presented with macrosomia (mean birthweight 4.26 kg) and hyperinsulinaemic hypoglycaemia soon after birth (median age 1 day). All three (age range 7 months to 11 years 10 months) remain on diazoxide therapy, with dose requirements increasing in one patient. There was no prior family history of diabetes, neonatal hypoglycaemia or macrosomia. Parents were screened for HNF4A mutations post-diagnosis and one father was subsequently found to have maturity-onset diabetes of the young.

CONCLUSIONS

This case series follows the evolving course of three patients with confirmed HNF4A-mediated congenital hyperinsulinism, highlighting (1) the variable natural history of these mutations, (2) the potential for prolonged diazoxide requirement, even into adolescence, and (3) the need for screening, regardless of family history.