Standardised practices in the networked management of congenital hyperinsulinism: a UK national collaborative consensus

Congenital hyperinsulinism (CHI) is a condition characterised by severe and recurrent hypoglycaemia in infants and young children caused by inappropriate insulin over-secretion. CHI is of heterogeneous aetiology with a significant genetic component and is often unresponsive to standard medical therapy options. The treatment of CHI can be multifaceted and complex, requiring multidisciplinary input. It is important to manage hypoglycaemia in CHI promptly as the risk of long-term neurodisability arising from neuroglycopaenia is high. The UK CHI consensus on the practice and management of CHI was developed to optimise and harmonise clinical management of patients in centres specialising in CHI as well as in non-specialist centres engaged in collaborative, networked models of care. Using current best practice and a consensus approach, it provides guidance and practical advice in the domains of diagnosis, clinical assessment and treatment to mitigate hypoglycaemia risk and improve long term outcomes for health and well-being.

Bridging the gaps: recent advances in diagnosis, care, and outcomes in congenital hyperinsulinism

PURPOSE OF REVIEW

To highlight advances in congenital hyperinsulinism (HI), including newly described molecular mechanisms of disease, novel therapeutic interventions, and improved understanding of long-term outcomes.

RECENT FINDINGS

Important advances have been made elucidating the molecular mechanisms responsible for HI. Non-coding variants in HK1 have been found to cause aberrant hexokinase expression. Inactivating mutations in SLC25A36 have been identified in children with features of the hyperinsulinism hyperammonemia syndrome. Low-level mosaic mutations in known HI genes have been detected in cases of 'genetic testing negative' HI. Identification and localization of focal HI lesions remains a priority, since focal HI can be cured with surgery. Use of 68 Ga-NODAGA-exendin-4 PET has been proposed to localize focal lesions. Additional studies are needed before this technique replaces 18 F-DOPA PET as standard of care. Treatment options for children with diffuse HI remain limited. The long-acting somatostatin analog, lanreotide, was shown to significantly improve glycemic control in a large series of children with HI. New therapies are under development, with promising preliminary results. Long-term quality of life and neurodevelopmental outcomes remain suboptimal.

SUMMARY

Advanced genetic and epigenomic analytic techniques have uncovered novel molecular mechanisms of HI. Development of new drugs holds promise to improve long-term outcomes for individuals with HI.

Congenital hyperinsulinism in infancy and childhood: challenges, unmet needs and the perspective of patients and families

BACKGROUND

Congenital hyperinsulinism (CHI) is the most common cause of persistent hypoglycemia in infants and children, and carries a considerable risk of neurological damage and developmental delays if diagnosis and treatment are delayed. Despite rapid advances in diagnosis and management, long-term developmental outcomes have not significantly improved in the past years. CHI remains a disease that is associated with significant morbidity, and psychosocial and financial burden for affected families, especially concerning the need for constant blood glucose monitoring throughout patients' lives.

RESULTS

In this review, we discuss the key clinical challenges and unmet needs, and present insights on patients' and families' perspective on their daily life with CHI. Prevention of neurocognitive impairment and successful management of patients with CHI largely depend on early diagnosis and effective treatment by a multidisciplinary team of specialists with experience in the disease.

CONCLUSIONS

To ensure the best outcomes for patients and their families, improvements in effective screening and treatment, and accelerated referral to specialized centers need to be implemented. There is a need to develop a wider range of centers of excellence and networks of specialized care to optimize the best outcomes both for patients and for clinicians. Awareness of the presentation and the risks of CHI has to be raised across all professions involved in the care of newborns and infants. For many patients, the limited treatment options currently available are insufficient to manage the disease effectively, and they are associated with a range of adverse events. New therapies would benefit all patients, even those that are relatively stable on current treatments, by reducing the need for constant blood glucose monitoring and facilitating a personalized approach to treatment.

Molecular Characterization and Management of Congenital Hyperinsulinism: A Tertiary Centre Experience

Background

Objective

Study design

Participants

Outcomes

Results

Conclusions

Electronic Supplementary Material

Continuous Glucose Monitoring in the Management of Neonates With Persistent Hypoglycemia and Congenital Hyperinsulinism

BACKGROUND

Persistent hypoglycemia is common in the newborn and is associated with poor neurodevelopmental outcome. Adequate monitoring is critical in prevention, but is dependent on frequent, often hourly blood sampling. Continuous glucose monitoring (CGM) is increasingly being used in children with type 1 diabetes mellitus, but use in neonatology remains limited. We aimed to introduce real-time CGM to provide insights into patterns of dysglycemia and to support the management of persistent neonatal hypoglycemia.

METHODS

This is a single-center retrospective study of real-time CGM use over a 4-year period in babies with persistent hypoglycemia.

RESULTS

CGMs were inserted in 14 babies: 8 term and 6 preterm infants, 9 with evidence of congenital hyperinsulinism (CHI). A total of 224 days of data was collected demonstrating marked fluctuations in glucose levels in babies with CHI, with a higher sensor glucose SD (1.52 ± 0.79 mmol/L vs 0.77 ± 0.22 mmol/L) in infants with CHI compared with preterm infants. A total of 1254 paired glucose values (CGM and blood) were compared and gave a mean absolute relative difference of 11%.

CONCLUSION

CGM highlighted the challenges of preventing hypoglycemia in these babies when using intermittent blood glucose levels alone, and the potential application of CGM as an adjunct to clinical care.

Global Registries in Congenital Hyperinsulinism

Congenital hyperinsulinism (HI) is the most frequent cause of severe, persistent hypoglycemia in newborn babies and children. There are many areas of need for HI research. Some of the most critical needs include describing the natural history of the disease, research leading to new and better treatments, and identifying and managing hypoglycemia before it is prolonged and causes brain damage or death. Patient-reported data provides a basis for understanding the day-to-day experience of living with HI. Commonly identified goals of registries include performing natural history studies, establishing a network for future product and treatment studies, and supporting patients and families to offer more successful and coordinated care. Congenital Hyperinsulinism International (CHI) created the HI Global Registry (HIGR) in October 2018 as the first global patient-powered hyperinsulinism registry. The registry consists of thirteen surveys made up of questions about the patient's experience with HI over their lifetime. An international team of HI experts, including family members of children with HI, advocates, clinicians, and researchers, developed the survey questions. HIGR is managed by CHI and advised by internationally recognized HI patient advocates and experts. This paper aims to characterize HI through the experience of individuals who live with it. This paper includes descriptive statistics on the birthing experience, hospitalizations, medication management, feeding challenges, experiences with glucose monitoring devices, and the overall disease burden to provide insights into the current data in HIGR and demonstrate the potential areas of future research. As of January 2022, 344 respondents from 37 countries consented to participate in HIGR. Parents or guardians of individuals living with HI represented 83.9% of the respondents, 15.3% were individuals living with HI. Data from HIGR has already provided insight into access challenges, patients' and caregivers' quality of life, and to inform clinical trial research programs. Data is also available to researchers seeking to study the pathophysiology of HI retrospectively or to design prospective trials related to improving HI patient outcomes. Understanding the natural history of the disease can also guide standards of care. The data generated through HIGR provides an opportunity to improve the lives of all those affected by HI.

Congenital Hyperinsulinism International: A Community Focused on Improving the Lives of People Living With Congenital Hyperinsulinism

Congenital hyperinsulinism (HI) is a rare disease affecting newborns. HI causes severe hypoglycemia due to the overproduction of insulin. The signs and symptoms of hypoglycemia in HI babies is often not discovered until brain damage has already occurred. Prolonged hypoglycemia from HI can even lead to death. Disease management is often complex with a high burden on caregivers. Treatment options are extremely limited and often require long hospital stays to devise. Cascading from suboptimal treatments and diagnostic practices are a host of other problems and challenges that many with HI and their families experience including continued fear of hypoglycemia and feeding problems. The aim of this paper is (1) to describe the current challenges of living with HI including diagnosis and disease management told from the perspective of people who live with the condition (2), to provide family stories of life with HI, and (3) to share how a rare disease patient organization, Congenital Hyperinsulinism International (CHI) is working to improve the lives of HI patients and their families. CHI is a United States based nonprofit organization with a global focus. The paper communicates the programs the patient advocacy organization has put into place to support HI families through its virtual and in-person gatherings. The organization also helps individuals access diagnostics, medical experts, and treatments. CHI also raises awareness of HI to improve patient outcomes with information about HI and prolonged hypoglycemia in twenty-three languages. CHI drives innovation for new and better treatments by funding research pilot grants, conducting research through the HI Global Registry, and providing patient experience expertise to researchers developing new treatments. The organization is also the sponsor of the CHI Collaborative Research Network which brings medical and scientific experts together for the development of a patient-focused prioritized research agenda.

Recent updates in the management of infants and children with hyperinsulinism

PURPOSE OF REVIEW

To highlight recent advances in early diagnosis and the changing treatment paradigm for hyperinsulinism (HI) which can result in shorter hospitalizations, higher rates of cure and improved neurological outcome.

RECENT FINDINGS

Recent literature has shown that following publication of the pediatric endocrinology society guidelines for diagnosing hypoglycemia there have been higher rates of diagnosis of acquired and genetic HI. Studies of neurological outcome have found that poor outcomes are associated with delay between initial hypoglycemia and instigation of treatment for HI, hypoglycemic seizures and frequency of glucose <20 mg/dL. Rapid genetic testing can decrease the time from the discovery of diazoxide unresponsiveness to referral to multidisciplinary centers with the availability of 18-F-L 3,4-Dihydroxyphenylalanine positron emission tomography (18F-DOPA PET). Proper selection of patients for 18F-DOPA PET and careful interpretation of the images can result in greater than 90% cure for patients with focal HI.

SUMMARY

Recent advances in the early diagnosis of HI and rapid turnaround genetic testing can lead to prompt transfer to centers with multidisciplinary care teams where proper selection of patients for 18F-DOPA PET scan gives the best opportunity for cure for patients with focal disease. Minimizing severe hypoglycemia maximizes the opportunity for improved neurological outcome.

Long-Term Outcome and Treatment in Persistent and Transient Congenital Hyperinsulinism: A Finnish Population-Based Study

CONTEXT

The management of congenital hyperinsulinism (CHI) has improved.

OBJECTIVE

To examine the treatment and long-term outcome of Finnish patients with persistent and transient CHI (P-CHI and T-CHI).

DESIGN

A population-based retrospective study of CHI patients treated from 1972 to 2015.

PATIENTS

106 patients with P-CHI and 132 patients with T-CHI (in total, 42 diagnosed before and 196 after year 2000) with median follow-up durations of 12.5 and 6.2 years, respectively.

MAIN OUTCOME MEASURES

Recovery, diabetes, pancreatic exocrine dysfunction, neurodevelopment.

RESULTS

The overall incidence of CHI (n = 238) was 1:11 300 live births (1972-2015). From 2000 to 2015, the incidence of P-CHI (n = 69) was 1:13 500 and of T-CHI (n = 127) 1:7400 live births. In the 21st century P-CHI group, hyperinsulinemic medication was initiated and normoglycemia achieved faster relative to earlier. Of the 74 medically treated P-CHI patients, 68% had discontinued medication. Thirteen (12%) P-CHI patients had partial pancreatic resection and 19 (18%) underwent near-total pancreatectomy. Of these, 0% and 84% developed diabetes and 23% and 58% had clinical pancreatic exocrine dysfunction, respectively. Mild neurological difficulties (21% vs 16%, respectively) and intellectual disability (9% vs 5%, respectively) were as common in the P-CHI and T-CHI groups. However, the 21st century P-CHI patients had significantly more frequent normal neurodevelopment and significantly more infrequent diabetes and pancreatic exocrine dysfunction compared with those diagnosed earlier.

CONCLUSIONS

Our results demonstrated improved treatment and long-term outcome in the 21st century P-CHI patients relative to earlier.

Hyperinsulinemic hypoglycemia in children and adolescents: Recent advances in understanding of pathophysiology and management

Hyperinsulinemic hypoglycemia (HH) is characterized by unregulated insulin release, leading to persistently low blood glucose concentrations with lack of alternative fuels, which increases the risk of neurological damage in these patients. It is the most common cause of persistent and recurrent hypoglycemia in the neonatal period. HH may be primary, Congenital HH (CHH), when it is associated with variants in a number of genes implicated in pancreatic development and function. Alterations in fifteen genes have been recognized to date, being some of the most recently identified mutations in genes HK1, PGM1, PMM2, CACNA1D, FOXA2 and EIF2S3. Alternatively, HH can be secondary when associated with syndromes, intra-uterine growth restriction, maternal diabetes, birth asphyxia, following gastrointestinal surgery, amongst other causes. CHH can be histologically characterized into three groups: diffuse, focal or atypical. Diffuse and focal forms can be determined by scanning using fluorine-18 dihydroxyphenylalanine-positron emission tomography. Newer and improved isotopes are currently in development to provide increased diagnostic accuracy in identifying lesions and performing successful surgical resection with the ultimate aim of curing the condition. Rapid diagnostics and innovative methods of management, including a wider range of treatment options, have resulted in a reduction in co-morbidities associated with HH with improved quality of life and long-term outcomes. Potential future developments in the management of this condition as well as pathways to transition of the care of these highly vulnerable children into adulthood will also be discussed.

Delayed Resolution of Feeding Problems in Patients With Congenital Hyperinsulinism

Background: Congenital Hyperinsulinism (CHI) is the most common cause of recurrent and severe hypoglycaemia in childhood. Feeding problems occur frequently in severe CHI but long-term persistence and rates of resolution have not been described. Methods: All patients with CHI admitted to a specialist center during 2015-2016 were assessed for feeding problems at hospital admission and for three years following discharge, through a combination of specialist speech and language therapy review and parent-report at clinical contact. Results: Twenty-five patients (18% of all patients admitted) with CHI were prospectively identified to have feeding problems related to sucking (n = 6), swallowing (n = 2), vomiting (n = 20), and feed aversion (n = 17) at the time of diagnosis. Sixteen (64%) patients required feeding support by nasogastric/gastrostomy tubes at diagnosis; tube feeding reduced to 4 (16%) patients by one year and 3 (12%) patients by three years. Feed aversion resolved slowly with mean time to resolution of 240 days after discharge; in 15 patients followed up for three years, 6 (24%) continued to report aversion. The mean time (days) to resolution of feeding problems was lower in those who underwent lesionectomy (n = 4) than in those who did not (30 vs. 590, p = 0.009) and significance persisted after adjustment for associated factors (p = 0.015). Conclusion: Feeding problems, particularly feed aversion, are frequent in patients with CHI and require support over several years. By contrast, feeding problems resolve rapidly in patients with focal CHI undergoing curative lesionectomy, suggesting the association of feeding problems with hyperinsulinism.

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.

Therapies and outcomes of congenital hyperinsulinism-induced hypoglycaemia

Congenital hyperinsulinism is a rare disease, but is the most frequent cause of persistent and severe hypoglycaemia in early childhood. Hypoglycaemia caused by excessive and dysregulated insulin secretion (hyperinsulinism) from disordered pancreatic β cells can often lead to irreversible brain damage with lifelong neurodisability. Although congenital hyperinsulinism has a genetic cause in a significant proportion (40%) of children, often being the result of mutations in the genes encoding the K_ATP channel (ABCC8 and KCNJ11), not all children have severe and persistent forms of the disease. In approximately half of those without a genetic mutation, hyperinsulinism may resolve, although timescales are unpredictable. From a histopathology perspective, congenital hyperinsulinism is broadly grouped into diffuse and focal forms, with surgical lesionectomy being the preferred choice of treatment in the latter. In contrast, in diffuse congenital hyperinsulinism, medical treatment is the best option if conservative management is safe and effective. In such cases, children receiving treatment with drugs, such as diazoxide and octreotide, should be monitored for side effects and for signs of reduction in disease severity. If hypoglycaemia is not safely managed by medical therapy, subtotal pancreatectomy may be required; however, persistent hypoglycaemia may continue after surgery and diabetes is an inevitable consequence in later life. It is important to recognize the negative cognitive impact of early-life hypoglycaemia which affects half of all children with congenital hyperinsulinism. Treatment options should be individualized to the child/young person with congenital hyperinsulinism, with full discussion regarding efficacy, side effects, outcomes and later life impact.

[Actual trends in diagnostics and treatment of congenital hyperinsulinism]

Congenital hyperinsulinism (CHI) is the most common cause of severe persistent hypoglycemia in neonates and infants. Early diagnosis and effective treatment (based on the principles of pharmacogenetics) play the key role for the prognosis. The DNA anlysis, which can identify mutation in one of the 11 genes causing MODY, is crutial in the diagnostics. Moreover, The genotype determines also the optimal therapy approach (medicaments, diet or rarely surgery). There was a large progress of novel medicaments treating particularly most severe (diazoxide-resistant) forms of CHI.Key words: congenital hyperinsulinism - diazoxid - DNA analysis - hypoglycemia - somatostatine analogues.

Integrating genetic and imaging investigations into the clinical management of congenital hyperinsulinism

Congenital Hyperinsulinism (CHI) is a rare but important cause of hypoglycaemia in infancy. CHI is a heterogeneous disease, but has a strong genetic basis; a number of genetic causes have been identified with CHI in about a third of individuals, chiefly in the genes that code for the ATP sensitive K(+) channels (KATP ) in the pancreatic β-cells. Rapid KATP channel gene testing is a critical early step in the diagnostic algorithm of CHI, with paternal heterozygosity correlating with the occurrence of focal lesions. Imaging investigations to diagnose and localize solitary pancreatic foci have evolved over the last decade with (18)F-DOPA PET-CT scanning as the current diagnostic tool of choice. Although clinical management of CHI has improved significantly with the application of genetic screening and imaging investigations, much remains to be uncovered. This includes a better understanding of the molecular mechanisms for dysregulated insulin release in those patients without known genetic mutations, and the development of biomarkers that could characterize CHI, including long-term prognosis and targeted treatment planning, i.e. 'personalised medicine'. From the perspective of pancreatic imaging, it would be important to achieve greater specificity of diagnosis not only for focal lesions but also for diffuse and atypical forms of the disease.

[Congenital hyperinsulinism--novel insights into etiology, diagnosis and treatment]

Congenital hyperinsulinism (CHI) is a major cause of persistent hypoglycemia in the neonatal and early infancy periods. Althought the disease is relatively rare with incidence of about 1:25 000-50 000 live births, the importance of the disease should not be underestimated. Namely, prompt recognition and management of patients with CHI is essential, if permanent neurological impairment is to be avoided. CHI is caused by mutations in one of the 7 genes involved in the regulation of insulin secretion in pancreatic beta-cells. It is important to introduce specific medical therapy as soon as diagnosis is established. Severe, neonatal forms of CHI are often resistant to medications, thus they require surgical procedure. The preoperative genetic testing and scintigraphy are indicated to distinguish histological subtypes of the disease (focal vs. diffuse CHI). Patients with focal disease are usually cured after pancreatic resection, while diffuse disease has much worse prognosis. This manuscript offers novel insights into CHI and emphasizes the role of early diagnosis as crucial for succesful treatment that was recently enriched with novel options.

Hyperinsulinaemic hypoglycaemia: genetic mechanisms, diagnosis and management

Hyperinsulinaemic hypoglycaemia (HH) is due to the unregulated secretion of insulin from pancreatic β-cells. A rapid diagnosis and appropriate management of these patients is essential to prevent the potentially associated complications like epilepsy, cerebral palsy and neurological impairment. The molecular basis of HH involves defects in key genes (ABCC8, KCNJ11, GLUD1, GCK, HADH, SLC16A1, HNF4A and UCP2) which regulate insulin secretion. The most severe forms of HH are due to loss of function mutations in ABCC8/KCNJ11 which encode the SUR1 and KIR6.2 components respectively of the pancreatic β-cell K(ATP) channel. At a histological level there are two major forms (diffuse and focal) each with a different genetic aetiology. The diffuse form is inherited in an autosomal recessive (or dominant) manner whereas the focal form is sporadic in inheritance and is localised to a small region of the pancreas. The focal form can now be accurately localised pre-operatively using a specialised positron emission tomography scan with the isotope Fluroine-18L-3, 4-dihydroxyphenyalanine (18F-DOPA-PET). Focal lesionectomy can provide cure from the hypoglycaemia. However the diffuse form is managed medically or by near total pancreatectomy (with high risk of diabetes mellitus). Recent advances in molecular genetics, imaging with 18F-DOPA-PET/CT and novel surgical techniques have changed the clinical approach to patients with HH.

Dominantly acting ABCC8 mutations in patients with medically unresponsive hyperinsulinaemic hypoglycaemia

Recessive inactivating mutations in the ABCC8 and KCNJ11 genes encoding the adenosine triphosphate-sensitive potassium (K(ATP)) channel subunit sulphonylurea receptor 1 (SUR1) and inwardly rectifying potassium channel subunit (Kir6.2) are the most common cause of hyperinsulinaemic hypoglycaemia (HH). Most of these patients do not respond to treatment with the (K(ATP)) channel agonist diazoxide. Dominant inactivating ABCC8 and KCNJ11 mutations are less frequent, but are usually associated with a milder form of hypoglycaemia that is responsive to diazoxide therapy. We studied five patients from four families with HH who were unresponsive to diazoxide and required a near total pancreatectomy. Mutations in KCNJ11 and ABCC8 were sought by sequencing and dosage analysis. Three novel heterozygous ABCC8 mis-sense mutations (G1485E, D1506E and M1514K) were identified in four probands. All the mutations affect residues located within the Nucleotide Binding Domain 2 of the SUR1 subunit. Testing of family members showed that the mutations had arisen de novo with dominant inheritance in one pedigree. This study extends the clinical phenotype associated with dominant (K(ATP)) channel mutations to include severe congenital HH requiring near total pancreatectomy in addition to a milder form of diazoxide responsive hypoglycaemia. The identification of dominant vs recessive mutations does not predict clinical course but it is important for estimating the risk of HH in future siblings and offspring.

The contribution of rapid KATP channel gene mutation analysis to the clinical management of children with congenital hyperinsulinism

OBJECTIVE

In children with congenital hyperinsulinism (CHI), K(ATP) channel genes (ABCC8 and KCNJ11) can be screened rapidly for potential pathogenic mutations. We aimed to assess the contribution of rapid genetic testing to the clinical management of CHI.

DESIGN

Follow-up observational study at two CHI referral hospitals.

METHODS

Clinical outcomes such as subtotal pancreatectomy, (18)F-Dopa positron emission tomography-computed tomography (PET-CT) scanning, stability on medical treatment and remission were assessed in a cohort of 101 children with CHI.

RESULTS

In total, 32 (32%) children had pathogenic mutations in K(ATP) channel genes (27 in ABCC8 and five in KCNJ11), of which 11 (34%) were novel. In those negative at initial screening, other mutations (GLUD1, GCK, and HNF4A) were identified in three children. Those with homozygous/compound heterozygous ABCC8/KCNJ11 mutations were more likely to require a subtotal pancreatectomy CHI (7/10, 70%). Those with paternal heterozygous mutations were investigated with (18)F-Dopa PET-CT scanning and 7/13 (54%) had a focal lesionectomy, whereas four (31%) required subtotal pancreatectomy for diffuse CHI. Those with maternal heterozygous mutations were most likely to achieve remission (5/5, 100%). In 66 with no identified mutation, 43 (65%) achieved remission, 22 (33%) were stable on medical treatment and only one child required a subtotal pancreatectomy.

CONCLUSIONS

Rapid genetic analysis is important in the management pathway of CHI; it provides aetiological confirmation of the diagnosis, indicates the likely need for a subtotal pancreatectomy and identifies those who require (18)F-Dopa PET-CT scanning. In the absence of a mutation, reassurance of a favourable outcome can be given early in the course of CHI.

Congenital hyperinsulinism and neonatal diabetes mellitus

This special edition of the Reviews in Metabolic and Endocrine Disorders provides a state of the state update on congenital hyperinsulinism and neonatal diabetes mellitus. Understanding the molecular mechanisms of these two disorders has provided fundamental insights into pancreatic beta-cell physiology. This knowledge has also had a significant impact on our clinical approach to patients with these two disorders and fundamentally changed patient management.

Persistent hyperinsulinemic hypoglycemia of infancy associated with congenital neuroblastoma: a case report

The authors report a rare case of persistent hyperinsulinemic hypoglycemia of infancy (PHHI) with congenital neuroblastoma without feature(s) of Beckwith-Wiedemann syndrome. A term newborn with a birth weight of 3,900 g developed hypoglycemia one hour after birth and required up to 20 mg/kg/min of intravenous glucose infusion to maintain euglycemia. Investigations during the critical period revealed an inappropriately high insulin level. An abdominal CT scan revealed a normal pancreas, right suprarenal mass, and liver nodules. A condition of stage 4S neuroblastoma was suspected and supported by an increased ratio of urine vanillylmandelic acid to creatinine. The bone marrow smear was normal. She underwent near total pancreatectomy at the age of 2 months. The suprarenal mass and liver nodules were not found during the operation or during repeated abdominal CT scans at 3 month of age. Spontaneous regression of neuroblastoma was suspected. The pathology of the pancreas was compatible with PHHI.

Surgical versus non-surgical treatment of congenital hyperinsulinism

Congenital hyperinsulinism is a functional disorder of insulin secretion. In its diffuse severe form, it is traditionally treated with over 95% pancreatectomy. However, even after this procedure normoglycemia is not always achieved. Non-surgical therapy with frequent or continuous feeding, medication and close monitoring is another alternative. In this review we compare the two approaches to this condition focusing on early complications, diabetes, neurological outcome and home management issues. Early complications of pancreatectomy include mechanical, metabolic and infectious complications. Non-surgical interventions can be complicated by unwarranted effects of medications and of invasive procedures. Diabetes occurs with both approaches but much less frequently and years later with non-surgical treatment. Regarding neurodevelopmental outcome, most data come from heterogeneous groups. Nevertheless, it appears that outcome is not adversely affected by avoiding surgery. Home management is far more difficult for the non-surgical form. When the non-surgical approach is successful in achieving normoglycemia and parents are highly motivated, this mode of therapy should be considered.

Long-term neurodevelopmental outcome in conservatively treated congenital hyperinsulinism

BACKGROUND

Congenital hyperinsulinism (CH) is treated surgically in many centers (near-total and partial pancreatectomy for diffuse and focal disease respectively). Most patients treated with near-total pancreatectomy developed diabetes during childhood/puberty. CH patients are at increased risk of neurodevelopmental disorders, some being severe, which are reported to occur in 14-44% of patients from highly heterogenous cohorts. Over the last few decades, we have treated children with CH conservatively without surgery. The aim of this study was to assess the neurodevelopmental outcome of these patients.

DESIGN AND METHODS

The study included 21 Ashkenazi CH medically treated patients: 11 homozygotes (diffuse disease) and 9 heterozygotes with mutations on the paternal allele (presumed focal disease). The mean age was 13.7 years (range 8-23). Neurodevelopmental outcomes were assessed by telephone interviews of parents, using a standard questionnaire. Closest age siblings of CH patients served as controls.

RESULTS

Ten CH patients had perinatal seizures of short duration. Four had post-neonatal seizures, which remitted entirely. During early childhood, four patients (19%) had hypotonia, eight (38%) had fine motor problems, seven (33%) had gross motor problems (clumsiness), and one had mild cerebral palsy. Three patients (14%) had speech problems. Eight patients required developmental therapy, compared to one in the control group. Most of these problems were resolved by age 4-5 years. At school age, all were enrolled in regular education, some excelled in their studies, 6 out of 21 patients (29%) had learning problems (2 out of 21 controls). None had overt diabetes.

CONCLUSIONS

Good neurodevelopmental outcome was observed in our conservatively treated CH patients, with no diabetes as reported in patients undergoing pancreatectomy.

Neonatal hyperinsulinism: clinicopathologic correlation

Neonatal hyperinsulinism is a life-threatening disease that, when treated by total pancreatectomy, leads to diabetes and pancreatic insufficiency. A more conservative approach is now possible since the separation of the disease into a nonrecurring focal form, which is cured by partial surgery, and a diffuse form, which necessitates total pancreas removal only in cases of medical treatment failure. The pathogenesis of the disease is now divided into K-channel disease (hyperinsulinemic hypoglycemia, familial [HHF] 1 and 2), which can mandate surgery, and other metabolic causes, HHF 3 to 6, which are treated medically in most patients. The diffuse form is inherited as a recessive gene on chromosome 11, whereas most cases of the focal form are caused by a sulfonylurea receptor 1 defect inherited from the father, which is associated with a loss of heterozygosity on the corresponding part of the mother's chromosome 11. The rare bifocal forms result from a maternal loss of heterozygosity specific to each focus. Paternal disomy of chromosome 11 is a rare cause of a condition similar to Beckwith-Wiedemann syndrome. A preoperative PET scan with fluorodihydroxyphenylalanine and perioperative frozen-section confirmation are the types of studies done before surgery when needed. Adult variants of the disease are less well defined at the present time.

Mechanisms of Disease: advances in diagnosis and treatment of hyperinsulinism in neonates

Hyperinsulinism is the single most common mechanism of hypoglycemia in neonates. Dysregulated insulin secretion is responsible for the transient and prolonged forms of neonatal hypoglycemia, and congenital genetic disorders of insulin regulation represent the most common of the permanent disorders of hypoglycemia. Mutations in at least five genes have been associated with congenital hyperinsulinism: they encode glucokinase, glutamate dehydrogenase, the mitochondrial enzyme short-chain 3-hydroxyacyl-CoA dehydrogenase, and the two components (sulfonylurea receptor 1 and potassium inward rectifying channel, subfamily J, member 11) of the ATP-sensitive potassium channels (K(ATP) channels). K(ATP) hyperinsulinism is the most common and severe form of congenital hyperinsulinism. Infants suffering from K(ATP) hyperinsulinism present shortly after birth with severe and persistent hypoglycemia, and the majority are unresponsive to medical therapy, thus requiring pancreatectomy. In up to 40-60% of the children with K(ATP) hyperinsulinism, the defect is limited to a focal lesion in the pancreas. In these children, local resection results in cure with avoidance of the complications inherent to a near-total pancreatectomy. Hyperinsulinism can also be part of other disorders such as Beckwith-Wiedemann syndrome and congenital disorders of glycosylation. The diagnosis and management of children with congenital hyperinsulinism requires a multidisciplinary approach to achieve the goal of therapy: prevention of permanent brain damage due to recurrent hypoglycemia.

Hyperinsulinism in infancy--genetic aspects

Hyperinsulinism in infancy (HI) is a heterogeneous disorder with respect to clinical presentation, genetics, histology and response to therapy. Advances in the understanding of the molecular basis of the disease have given the pediatric endocrinologists a better insight into the diagnosis and therapeutic choice. In 50-60% of cases, a genetic etiology is unraveled. Mutations in the genes encoding SUR1 (ABCC8) and KIR6.2 (KCNJ11) are the most frequent genetic causes of HI followed by mutations in the GLUD1 gene which encodes glutamate dehydrogenase (GDH) enzyme. The patients with GLUD1 mutations also have hyperammonemia (HA). Activating dominant mutations in glucokinase (GCK) gene which result in HI are rare. In GLUD1 and GCK mutations the disease is usually mild, has a late onset and is responsive to diazoxide. However, studies so far have failed to show a clear genotype phenotype relation in KATP channel mutations. In conclusion the genetic analysis of HI has provided valuable information to the clinicians about the beta cell.

The diagnosis of ectopic focal hyperinsulinism of infancy with [18F]-dopa positron emission tomography

BACKGROUND

Congenital hyperinsulinism (CHI) is a cause of severe hypoglycemia in the neonatal and infancy period. Histologically, there are two subtypes with diffuse and focal disease. The preoperative differentiation of these two forms is very important because the surgical management is radically different. The focal form of the disease can be cured if the focal lesion can be localized accurately and completely resected with surgery.

AIM

We report the case of a child who underwent three pancreatectomies with a choledochoduodenostomy and a cholecystectomy but continued to have severe hyperinsulinemic hypoglycemia.

METHODS/RESULTS

Radiological investigations including imaging with (18)fluoro-L-Dopa positron emission tomography scan showed a clear focus of increased (18)F-fluoro-L-Dopa uptake in the vicinity of the former head of the pancreas. On the magnetic resonance imaging scan, this focal uptake appeared to localize adjacent or next to duodenum (in the wall or cavity of the duodenum).

CONCLUSIONS

This unique case highlights the importance of correctly localizing and completely resecting the focal lesion in patients with CHI. (18)Fluoro-L-Dopa positron emission tomography scan can identify ectopic focal lesions in patients with CHI.

Hiperinsulinismo congénito. Revisión de 22 casos

INTRODUCTION

Congenital hyperinsulinism (CHI) is the most common cause of recurrent episodes of hypoglycemia in early childhood and consists of a group of distinct genetic disorders causing dysregulation of insulin secretion.

OBJECTIVE

To review the presentation, management and outcome of patients with CHI attended at our hospital.

MATERIAL AND METHODS

A retrospective review of all patients diagnosed with CHI between 1982 and 2004 was performed. Data were collected on age, gender, clinical presentation, medical and surgical management, and complications.

RESULTS

Twenty-two patients were identified. Notable features were early symptom onset in 80 %, pancreatectomy in 72 %, and neurological sequels in 28 % (abnormal neurodevelopment in 22 % and epilepsy in 13 %).

CONCLUSIONS

The presentation, management and outcome in our patients were similar to those in other series, indicating the need for early diagnosis and treatment to avoid neurological sequels.

Congenital hyperinsulinism

Congenital hyperinsulinism is a cause of persistent hypoglycaemia in the neonatal period. It is a heterogeneous disease with respect to clinical presentation, molecular biology, genetic aetiology and response to medical therapy. The clinical heterogeneity may range from severe life-threatening disease to very mild clinical symptoms. Recent advances have begun to clarify the molecular pathophysiology of this disease, but despite these advances treatment options remain difficult and there are many long-term complications. So far mutations in five different genes have been identified in patients with congenital hyperinsulinism. Most cases are caused by mutations in genes coding for either of the two subunits of the beta-cell K(ATP) channel (ABCC8 and KCNJ11). Two histological subtypes of the disease - diffuse and focal - have been described. The preoperative histological differentiation of these two subtypes is now mandatory as surgical management will be radically different. The ability to distinguish diffuse from focal lesions has profound implications for therapeutic approaches, prognosis and genetic counselling.

Effects of hypoglycemia on developmental outcome in children with congenital hyperinsulinism

Children with congenital hyperinsulinism are at risk for recurring, severe episodes of hypoglycemia that can cause seizures, brain damage, and developmental delay. To assess the frequency of permanent brain damage in this disorder, we carried out a telephone survey of 68 children who presented to The Children's Hospital of Philadelphia between 1980 and 2000. One third of the group had some degree of developmental delay. Those presenting in the first week of life and those with medically unresponsive hyperinsulinism were more likely to have delays. Early recognition and control of hypoglycemia are essential for preventing developmental delay in these children.

Contemporary strategies in the diagnosis and management of neonatal hyperinsulinaemic hypoglycaemia

Congenital hyperinsulinism (CHI) is a genetically and phenotypically diverse syndrome. Key management issues involve early diagnosis by ensuring that appropriate samples are taken at the point of hypoglycaemia, prevention of recurrent hypoglycaemia, and detailed characterisation of the clinical, biochemical, and genetic features of each case. Infants with persistent diazoxide resistant CHI require evaluation at specialist referral centres equipped to differentiate those with focal (fo-HI) and diffuse (di-HI) pancreatic disease. Fo-HI is treated with selective pancreatic resection but di-HI is treated by surgery only if intensive medical management regimes are not efficacious.

[Persistent hyperinsulinemic hypoglycemia of the neonate]

Persistent hyperinsulinemic hypoglicemia of the neonate is a rare heterogenous disease (clinically, histologically, metabolically and genetically), which is characterized by inadequatly high insuline rates in the presence of severe hypoglicemia. Hyperinsulinism, rather a syndrome than a disease, of which the main metabolic feature is hypoglicemia and decreased concentration of free fatty acids and ketones in serum (insulin inhibits lypolisis and synthesizes ketonic bodies), presents a major diagnostic and therapeutic chalenge. The disease is often followed by brain atrophy contributed by the attacks of hypoglicemia. It is inherited as an autosomally recessive and autosomally dominant disease. The genetic defects is located on the short arm of the chromosome 11. The authors report a successfully applied conservative treatment in a neonate with persistent hyperinsulinemic hypoglicemia.

Hyperinsulinemic hypoglycemia of infancy: the challenge continues

Hypoglycemia due to hyperinsulinemia is the most common cause of persistent hypoglycemia in infants and children. Recent discoveries in the molecular and biochemical regulation of insulin secretion have dramatically increased our understanding of the disorders responsible for syndromes of hyperinsulinemic hypoglycemia. Here, we briefly review the current knowledge of disorders of the K(ATP) channel, activating mutations of glucokinase and glutamate dehydrogenase (GDH) and other disorders that may be associated with specific phenotypes and permit appropriate targeted therapies. Despite these advances, much remains to be learned. We do not understand the mechanisms or defects in many instances, including defective carbohydrate glycosylation syndromes and perinatal hypoxia, both of which may be associated with hyperinsulinemia. Most importantly, preoperative distinction between diffuse and focal lesions cannot be always reliably made even after selective arterial infusion with calcium, glucose or a sulfonylurea with concurrent hepatic venous sampling for insulin. The ability to distinguish diffuse from localized lesions has profound implications for therapeutic approaches, prognosis and genetic counseling. To date, about 50% of individuals with hyperinsulinemic hypoglycemia of infancy can be correctly categorized. Thus, the challenge continues.

[Congenital hyperinsulinism in 15 infants, 1981-1999; experiences and new insights]

OBJECTIVE

To report on a retrospective study into the diagnostics and treatment of infants with congenital hyperinsulinism (CHI; persistent hyperinsulinemic hypoglycaemia).

DESIGN

Retrospective and descriptive.

METHOD

The study included all 15 patients diagnosed with CHI at the St Radboud University Medical Centre, the Netherlands, from 1981 until 1999. Data gathered by systematically searching case-notes included: presentation, clinical admission, laboratory results, treatment and follow-up.

RESULTS

Four of the 15 infants were macrosomatic; 12 (80%) were presented within 4 days of birth, and the rest after the age of 5 months. Their symptoms were partially aspecific (feeding poorly, lethargy) and partially clear, corresponding to neuroglycopaenia (jitteryness, hypotonia). Nine infants experienced convulsions. The amount of glucose that had to be administered to achieve normoglycaemia (average: 16.9 mg/kg/min) was far above the basal requirement of 4-8 mg/kg/min. Ketone serum and free fatty acid values were lowered during a hypoglycaemic episode, hyperinsulinism was detected after repeated measurements. Five infants responded well to treatment with diazoxide. Ten children underwent subtotal pancreatectomy after which 4 remained normoglycaemic. Three of the 10 children who underwent surgery developed an exocrine pancreas dysfunction. We did not systematically examine neuropsychological development, but in 5 of the 15 children this was clearly disturbed.