Pancreatic exocrine and endocrine function after pancreatectomy for persistent hyperinsulinaemic hypoglycaemia of infancy

Laparoscopic Surgery for Focal-Form Congenital Hyperinsulinism Located in Pancreatic Head

BACKGROUND AND AIMS

Congenital hyperinsulinism of infancy (CHI) is a rare condition that may cause irreversible severe neurological damage in infants. For children in whom medical management fails, partial or near-total pancreatectomy is then required according to the type of lesion. Currently, open surgery of near-total pancreatic head resection is a mature technique for the treatment of focal-form CHI located in the head of the pancreas, but a minimally invasive laparoscopic procedure has not been reported yet. The aim of this study was to verify the feasibility, safety, and efficacy of laparoscopic pancreatic head resection and Roux-en-Y pancreaticojejunostomy for focal-form CHI.

METHODS

Two infants with persistent hypoglycemia and increased insulin levels were diagnosed with CHI and underwent laparoscopic near-total pancreatic head resection due to a suboptimal response to medical therapy and the likelihood of focal disease amenable to surgery. Clinical records, operative findings, and postoperative follow-up were collected and analyzed.

RESULTS

The operative duration was 300-330 min, and the intraoperative blood loss was minimal. The duration of postoperative abdominal drainage was 4-5 days. Neither intra- nor postoperative abdominal complications occurred. Oral feeding was resumed 3-4 days after the operation, and the blood glucose level was gradually stabilized to within the normal range. Normal blood glucose was observed in both patients over a follow-up period of 3-6 months.

CONCLUSIONS

Laparoscopic pancreatic head resection and Roux-en-Y pancreaticojejunostomy can be considered a safe and effective procedure with minimal morbidity and excellent outcomes for the treatment of focal CHI in the head of the pancreas.

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.

Characterization of diabetes following pancreatic surgery in patients with congenital hyperinsulinism

Background

Congenital hyperinsulinism (CHI) is the most common cause of persistent hypoglycaemia in infancy that leads to unfavourable neurological outcome if not treated adequately. In patients with severe diffuse CHI it remains under discussion whether pancreatic surgery should be performed or intensive medical treatment with the acceptance of recurrent episodes of mild hypoglycaemia is justified. Near-total pancreatectomy is associated with high rates of insulin-dependent diabetes mellitus and exocrine pancreatic insufficiency. Little is known about the management and long-term glycaemic control of CHI patients with diabetes after pancreatic surgery. We searched the German/Austrian DPV database and compared the course of 42 CHI patients with diabetes to that of patients with type 1 diabetes mellitus (T1DM). Study groups were compared at diabetes onset and after a follow-up period of 6.1 [3.3–9.7] (median [interquartile range]) years.

Results

The majority of CHI patients with diabetes were treated with insulin (85.2% [70.9–99.5] at diabetes onset, and 90.5% [81.2–99.7] at follow-up). However, compared to patients with T1DM, significantly more patients in the CHI group with diabetes were treated with conventional insulin therapy (47.8% vs. 24.4%, p = 0.03 at diabetes onset, and 21.1% vs. 6.4% at follow-up, p = 0.003), and only a small number of CHI patients were treated with insulin pumps. Daily insulin dose was significantly lower in CHI patients with diabetes than in patients with T1DM, both at diabetes onset (0.3 [0.2–0.5] vs. 0.6 IE/kg/d [0.4–0.8], p = 0.003) and follow-up (0.8 [0.4–1.0] vs. 0.9 [0.7–1.0] IE/kg/d, p = 0.02), while daily carbohydrate intake was comparable in both groups. Within the first treatment year, HbA1c levels were significantly lower in CHI patients with diabetes (6.2% [5.5–7.9] vs. 7.2% [6.5–8.2], p = 0.003), but increased to a level comparable to that of T1DM patients at follow-up. Interestingly, in CHI patients, the risk of severe hypoglycaemia tends to be higher only at diabetes onset (14.8% vs. 5.8%, p = 0.1).

Conclusions

In surgically treated CHI patients insulin treatment needs to be intensified in order to achieve good glycaemic control. Our data furthermore emphasize the need for improved medical treatment options for patients with diazoxide- and/or octreotide-unresponsive CHI.

Pancreatic endocrine and exocrine function in children following near-total pancreatectomy for diffuse congenital hyperinsulinism

Context

Congenital hyperinsulinism (CHI), the commonest cause of persistent hypoglycaemia, has two main histological subtypes: diffuse and focal. Diffuse CHI, if medically unresponsive, is managed with near-total pancreatectomy. Post-pancreatectomy, in addition to persistent hypoglycaemia, there is a very high risk of diabetes mellitus and pancreatic exocrine insufficiency.

Setting

International referral centre for the management of CHI.

Patients

Medically unresponsive diffuse CHI patients managed with near-total pancreatectomy between 1994 and 2012.

Intervention

Near-total pancreatectomy.

Main Outcome Measures

Persistent hypoglycaemia post near-total pancreatectomy, insulin-dependent diabetes mellitus, clinical and biochemical (faecal elastase 1) pancreatic exocrine insufficiency.

Results

Of more than 300 patients with CHI managed during this time period, 45 children had medically unresponsive diffuse disease and were managed with near-total pancreatectomy. After near-total pancreatectomy, 60% of children had persistent hypoglycaemia requiring medical interventions. The incidence of insulin dependent diabetes mellitus was 96% at 11 years after surgery. Thirty-two patients (72%) had biochemical evidence of severe pancreatic exocrine insufficiency (Faecal elastase 1<100 µg/g). Clinical exocrine insufficiency was observed in 22 (49%) patients. No statistically significant difference in weight and height standard deviation score (SDS) was found between untreated subclinical pancreatic exocrine insufficiency patients and treated clinical pancreatic exocrine insufficiency patients.

Conclusions

The outcome of diffuse CHI patients after near-total pancreatectomy is very unsatisfactory. The incidence of persistent hypoglycaemia and insulin-dependent diabetes mellitus is very high. The presence of clinical rather than biochemical pancreatic exocrine insufficiency should inform decisions about pancreatic enzyme supplementation.

Glucose metabolism in 105 children and adolescents after pancreatectomy for congenital hyperinsulinism

OBJECTIVE

To describe the long-term metabolic outcome of children with congenital hyperinsulinism after near-total or partial elective pancreatectomy.

RESEARCH DESIGN AND METHODS

Patients (n = 105: 58 diffuse and 47 focal congenital hyperinsulinism) received operations between 1984 and 2006. Follow-up consisted of periodic measurements of pre- and postprandial plasma glucose over 24 h, OGTT, and IVGTT. Cumulative incidence of hypo- or hyperglycemia/insulin treatment was estimated by Kaplan-Meier analysis.

RESULTS

After near-total pancreatectomy, 59% of children with diffuse congenital hyperinsulinism still presented mild or asymptomatic hypoglycemia that responded to medical treatments and disappeared within 5 years. One-third of the patients had both preprandial hypoglycemia and postprandial hyperglycemia. Hyperglycemia was found in 53% of the patients immediately after surgery; its incidence increased regularly to 100% at 13 years. The cumulative incidence of insulin-treated patients was 42% at 8 years and reached 91% at 14 years, but the progression to insulin dependence was very variable among the patients. Plasma insulin responses to IVGTT and OGTT correlated well with glycemic alterations. In focal congenital hyperinsulinism, hypoglycemia or hyperglycemia were rare, mild, and transient.

CONCLUSIONS

Patients with focal congenital hyperinsulinism are cured of hypoglycemia after limited surgery, while the outcome of diffuse congenital hyperinsulinism is very variable after near-total pancreatectomy. The incidence of insulin-dependent diabetes is very high in early adolescence.

Morphologic analysis of focal and diffuse forms of congenital hyperinsulinism

Congenital hyperinsulinism is clinically characterized by an inappropriate insulin secretion resulting in recurrent severe hypoglycemia. Nesidioblastosis, the proliferation of islet cells budding off from ducts, has been considered for years as the histologic lesion responsible for the syndrome. In our morphologic studies, we demonstrate that nesidioblastosis is not specific of the disease, which is actually not a single entity. Indeed, we recognize the existence of 2 different forms-a diffuse form and a focal form-and demonstrate that they can be differentiated by morphologic criteria, even on frozen sections during surgery. This histologic distinction directs the therapeutic approach because the patients experiencing the focal form of the syndrome can be completely cured by a very limited pancreatectomy. Molecular findings confirmed the reliability of this histologic distinction, showing a specific background for each form.

Down-regulation of Kir6.2 affects calcium influx and insulin secretion in HIT-T15 cells

In pancreatic beta cells, ATP-sensitive potassium (K(ATP)) channels are metabolic sensors that couple cell metabolism to electrical activity, and therefore K(ATP) channels regulate insulin secretion. We assume that down-regulating the expression of Kir6.2 subunits of K(ATP) channels may change calcium influx induced by glucose and insulin secretion regulated by K(ATP) channels. In our study, we employ Kir6.2-shRNA plasmid to downregulate Kir6.2 expression in HIT-T15 cells. Then, we research the effect of downregulation of Kir6.2 on K(ATP) current, cytoplasmic free Ca2+ concentration and insulin secretion. All results illustrate that downregulation of Kir6.2 subunits of K(ATP) channels in HIT-T15 cells affects K(ATP) current and insulin secretion, and fails to promote calcium influx. The results demonstrate the function of Kir6.2 subunits in electrophysiology characteristic, insulin secretion and calcium influx, and RNA interference provides a feasible alternative to study the function of Kir6.2 subunits in K(ATP) channels in different kinds of diabetes.

The laparoscopic approach toward hyperinsulinism in children

Hyperinsulinemic hypoglycemia (HH) in children requiring surgery is rare. Early HH can be the result of focal or diffuse pancreatic pathology. A number of genetic abnormalities in early HH have been identified, but in the majority of patients no abnormality is found. The sporadic focal and diffuse forms as well the autosomal recessive form are particularly therapy-resistant and demand for early surgery. Preoperative discrimination between focal and diffuse disease in early HH is difficult. 18 F DOPA PET in combination with CT is promising as is laparoscopic exploration of the pancreas. Frozen section biopsy analysis has not been uniformly beneficial. If macroscopically no focal lesion is found, limited laparoscopic distal pancreatectomy provides tissue for definitive pathologic examination. Subsequent near total laparoscopic spleen-saving pancreatectomy surgery is not particularly difficult. Later HH may occur in the context of the MEN-1 syndrome and is then multifocal in nature. In MEN-1 patients, a distal spleen-saving pancreatectomy with enucleation of lesions in the head seems justified. Insulin-producing lesions in non-MEN-1 patients should be enucleated. There should always be a suspicion of malignancy. Also, in older children, surgery for hyperinsulinism should be performed laparoscopically.

A case of persistent hyperinsulinemic hypoglycemia of infancy successfully managed with subcutaneous octreotide injection and nocturnal intravenous glucose supply

Persistent hyperinsulinemic hypoglycemia of infancy (PHHI) is often resistant to medical therapy and is normally treated by subtotal pancreatectomy to avoid neurological complications. However, many problems after surgery, such as recurrence of hypoglycemia and diabetes mellitus, remain to be solved. This report concerns a case of PHHI that was resistant to octreotide or diazoxide alone but was successfully controlled with subcutaneous injection of octreotide in combination with nocturnal glucose infusion through central venous catheter. The patient exhibited natural remission of hyperinsulinism with age, and all treatment was ceased at the age of 4 yr. Growth and neurological development of the patient have been normal. This combined therapy can be a therapeutic option as a substitute for surgical solutions.

Persistent Hyperinsulinaemic Hypoglycaemia of Infancy in 43 Children: Long-term Clinical and Surgical Follow-up

OBJECTIVE

To describe the clinical, surgical, biochemical, radiological and electrophysiological features of 43 Saudi children with persistent hyperinsulinaemic hypoglycaemia of infancy (PHHI) who have been followed since 1983.

METHODS

Data from 43 patients were retrospectively analysed. PHHI was diagnosed on the basis of high intravenous glucose requirement, high insulin to glucose ratio, negative urinary ketones and normal tandem mass spectrometry. The patients were assessed radiologically by brain magnetic resonance imaging and/or computed tomography and electrophysiologically by brain stem auditory evoked potential, visual evoked response and electroencephalogram. Patients who failed medical therapy received near total pancreatectomy.

RESULTS

The patients were severely hypoglycaemic and intolerant to fast. Hypoglycaemic convulsion was the most commonly presenting complaint. Eighteen patients were developmentally delayed and 14 of them had brain atrophy. All patients, except nine, did not respond to medical treatment and underwent surgery. Four pancreatectomized patients developed diabetes and two had malabsorption. One baby had 180 cm resection of gangrenous bowel most likely secondary to octreotide. No common bile duct injury was encountered. One patient was treated medically during childhood and developed diabetes and gained weight during adolescence.

CONCLUSION

PHHI is a relatively common and serious disease among Saudi children. Early intervention is necessary to avoid neurological damage in patients who are severely hypoglycaemic and unresponsive to medical therapy. Surgically and probably medically treated patients are at a high risk of developing diabetes, which could be the natural outcome of this disease. Care and spending time during surgery to visualize the common bile duct help in avoiding its injury.

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.

Multidisciplinary management of surgical disorders of the pancreas in childhood

OBJECTIVES

To describe the frequency and range of pancreatic disorders in children requiring surgical intervention and to highlight the importance of multidisciplinary management.

METHODS

An audit of all children under 17 years of age referred with surgical disorders of the pancreas or pancreatitis to a regional pediatric gastroenterology unit in the United Kingdom during a 10-year period. A retrospective chart review of clinical features, pathology and outcome was undertaken.

RESULTS

Surgical intervention was required for the following pancreatic disorders: persistent hyperinsulinemic hypoglycemia of infancy (n = 4), pancreatic tumors (n = 5), pancreaticobiliary malunion (n = 12), pancreatic trauma (n = 6) and pancreatitis (n = 10). The indications for surgery in acute pancreatitis were a persistent pseudocyst (n = 1) and treatment of an underlying cause of pancreatitis (n = 4); in chronic pancreatitis, surgery was used to treat symptomatic pancreatic duct strictures (n = 4). One child died of a progressive lymphoma but all others who underwent surgery are alive and well. All 33 children with acute pancreatitis, including four with pancreatic necrosis, survived.

CONCLUSIONS

Surgery for pancreatic disorders in children is rarely required but may be necessary a) for definitive management of primary pancreatic pathology, b) to treat sequelae of acute or chronic pancreatitis and c) to treat an underlying cause of pancreatitis. There is a broad spectrum of potential pathologies. These patients are best managed by a multidisciplinary team approach.

Hyperinsulinisme persistant du nouveau-né et du nourrisson : traitement chirurgical des lésions pancréatiques focales dans 60 cas

Congenital hyperinsulinism of infancy is a severe disease that leads to important brain damage. Two different forms of the disease have been identified by pathologists: a diffuse and a focal form. A specific genetic anomaly identified in focal forms has never been described in diffuse ones. However, for most of authors, failure of medical treatment results in near-total pancreatectomy in all cases, which ends in diabetus. The aim of this retrospective study was to assess the results of elective partial pancreatectomy performed in 60 cases of focal form of hyperinsulinism over the last 18 years. Fifty-eight patients were cured with euglycemia at both fasting and hyperglycaemic tests without insulin-dependent diabetes mellitus. One patient is still in hypoglycaemia from unrecognized lesion; insulin-dependent diabetes mellitus occurred in one case nine years after surgery (a near-total pancreatectomy has been performed because of unknown focal form, in 1985).

Normal pregnancy in a woman with nesidioblastosis treated with somatostatin analog octreotide

OBJECTIVE

We report the case of a 36-yr-old woman with nesidioblastosis treated throughout pregnancy with high doses of octreotide. We studied the course of blood glucose, foetal growth and development.

METHODS

Blood samples were obtained every month throughout pregnancy and taken at birth from the umbilical cord. Sonography was performed repeatedly to monitor foetal growth.

RESULTS

The daily dose of octreotide was adapted to blood glucose levels: a dose of 1000 microg was infused during the first part of pregnancy, then it was decreased step by step during the last trimester of gestation. An elective cesarean section was performed at 32 weeks of gestation. High octreotide concentrations were obtained during the first part of gestation (range 2888-5021 pg/ml). During the third trimester of pregnancy blood glucose increased despite high insulin levels attesting physiological insulin-resistance. Plasma levels of placental GH and IGF-1 levels were similar to those observed in a normal pregnancy. Despite the presence of octreotide in the umbilical cord, TSH, free T4, PRL and pituitary GH concentrations were normal at birth. The female newborn (weight 3520 g, length 52 cm) had no malformation, and presented with normal postnatal development.

CONCLUSION

Our study demonstrates that: 1) octreotide treatment can be effective in controlling endogenous hyperinsulinism during pregnancy; 2) octreotide does not affect physiological changes during pregnancy such as insulin-resistance or placental GH level; 3) exposure of the foetus to octreotide throughout pregnancy does not induce any malformation and does not affect foetal development.

Hyperinsulinism in Infancy: From Basic Science to Clinical Disease

Dunne, Mark J., Karen E. Cosgrove, Ruth M. Shepherd, Albert Aynsley-Green, and Keith J. Lindley. Hyperinsulinism in Infancy: From Basic Science to Clinical Disease. Physiol Rev 84: 239–275, 2004; 10.1152/physrev.00022.2003.—Ion channelopathies have now been described in many well-characterized cell types including neurons, myocytes, epithelial cells, and endocrine cells. However, in only a few cases has the relationship between altered ion channel function, cell biology, and clinical disease been defined. Hyperinsulinism in infancy (HI) is a rare, potentially lethal condition of the newborn and early childhood. The causes of HI are varied and numerous, but in almost all cases they share a common target protein, the ATP-sensitive K+channel. From gene defects in ion channel subunits to defects in β-cell metabolism and anaplerosis, this review describes the relationship between pathogenesis and clinical medicine. Until recently, HI was generally considered an orphan disease, but as parallel defects in ion channels, enzymes, and metabolic pathways also give rise to diabetes and impaired insulin release, the HI paradigm has wider implications for more common disorders of the endocrine pancreas and the molecular physiology of ion transport.

Variceal hemorrhage 18 years after pancreatectomy for nesidioblastosis: a case report and discussion

Nesidioblastosis is a rare condition that requires near-total pancreatectomy in a minority of cases. Splenic vein thrombosis resulting in gastric variceal hemorrhage has not been a previously reported complication from 95% pancreatectomy for this indication. A case is presented and the management of this unusual complication discussed.

Persistent hyperinsulinemic hypoglycemia of infancy--successful therapy with nifedipine

Recent studies have demonstrated a role for calcium channel blocking agents in the treatment of persistent hyperinsulinemic hypoglycemia of infancy. We report a 30 day old infant with PHHI whom we successfully treated with oral nifedipine alone.

Subtotal pancreatectomy for hypoglycemia due to congenital hyperinsulinism: long-term follow-up of neurodevelopmental and pancreatic function

OBJECTIVE

To evaluate neurodevelopmental status as well as endocrine and exocrine pancreatic function in children who have undergone subtotal pancreatectomy for hypoglycemia due to congenital hyperinsulinism.

PATIENTS AND METHODS

Out of 15 identified patients, eight children (mean age 12.7 +/- 0.8 yr) participated in detailed psychometric testing and studies assessing glucose homeostasis, secretion of proinsulin, insulin, glucagon and C-peptide during a test meal. Additionally, a 24-h fast, glucagon challenge test, 72-h stool collection, and ultrasonography of the pancreatic remnant were performed.

RESULTS

Five of the 15 initially identified children had seizure disorders, including two with mental retardation. Diabetes developed in two of 15 children. All eight children investigated in the present study had evidence for attentional control impairment and 50% had subnormal intellectual functioning. Two had symptomatic hypoglycemia during the 24-h fast, while one had an elevated fasting glucose concentration. Four children, including the latter patient, had proinsulin/insulin ratios resembling patients with type 2 diabetes. Exocrine pancreatic function was normal in all eight children. No correlation was found between pancreatic endocrine function and pancreatic remnant size, nor between multiple pre- and postoperative factors (i.e., age at diagnosis and surgery) and neurodevelopmental outcome.

CONCLUSION

While severe mental retardation or diabetes occurred infrequently in our patient population compared with previous reports, all of the studied children had subtle anomalies in their cognitive performance tests and the majority had endocrine test results indicative of abnormal insulin secretion and stressed pancreatic beta cells. Although partial pancreatectomy remains the treatment of choice after medical therapy fails, improved therapeutic means are necessary to achieve better clinical outcome.

Neurologic outcomes of 90 neonates and infants with persistent hyperinsulinemic hypoglycemia

OBJECTIVE

To evaluate the neurologic outcomes of neonates and infants suffering from persistent hyperinsulinemic hypoglycemia of infancy (PHHI).

METHODS

The neurologic development of 90 PHHI patients was studied retrospectively. Sixty-three patients were treated surgically and 27 were treated medically. Fifty-four patients were neonates, of whom 8 were treated medically and 46 were operated on (19 for a focal adenomatous hyperplasia and 27 for diffuse hyperinsulinism). Thirty-six patients had infancy-onset hyperinsulinism, of whom 19 were treated medically and 17 underwent pancreatectomy (10 patients for a focal adenomatous hyperplasia and 7 for diffuse hyperinsulinism).

RESULTS

Severe psychomotor retardation was found in 7 patients, 6 with neonatal-onset PHHI. Intermediate psychomotor disability existed in 12 patients; epilepsy existed in 16. Neonatal-onset was the main risk factor for severe retardation or epilepsy. Medically treated patients were less severely affected than those treated by surgery, and there was no difference between the diffuse and focal forms of hyperinsulinism.

CONCLUSION

Neonatal hyperinsulinemic hypoglycemia is still a severe disease with an important risk to rapidly develop severe mental retardation and epilepsy.

Management of hyperinsulinism in infancy and childhood

Hyperinsulinism (HI) in infancy presents a formidable challenge for the paediatrician as it is one of the most difficult problems to manage in contemporary paediatric endocrinology. Although there have been major advances in understanding the condition over the last five years, the neurological outcome remains poor choice, and the choice of treatments continue to be unsatisfactory. This review article updates the management of HI derived from a Consensus Workshop held by the European Network for Research into Hyperinsulinism (ENRHI) in 1999.