Surgical treatment of hyperinsulinaemic hypoglycaemia in infancy and childhood

Both Low Blood Glucose and Insufficient Treatment Confer Risk of Neurodevelopmental Impairment in Congenital Hyperinsulinism: A Multinational Cohort Study

BACKGROUND/AIMS

Congenital hyperinsulinism (CHI) is a heterogeneous disease most frequently caused by KATP-channel (ABCC8 and KCNJ11) mutations, with neonatal or later onset, variable severity, and with focal or diffuse pancreatic involvement as the two major histological types. CHI confers a high risk of neurological impairment; however, sparsely studied in larger patient series. We assessed the neurodevelopmental outcome in children with CHI at follow-up in a mixed international cohort.

METHODS

In two hyperinsulinism expert centers, 75 CHI patients were included (Russian, n = 33, referred non-Scandinavian, treated in Denmark n = 27, Scandinavian, n = 15). Hospital files were reviewed. At follow-up, neurodevelopmental impairment and neurodevelopmental, cognitive and motor function scores were assessed.

RESULTS

Median (range) age at follow-up was 3.7 years (3.3 months-18.2 years). Neurodevelopmental impairment was seen in 35 (47%). Impairment was associated with abnormal brain magnetic resonance imaging (MRI); odds ratio (OR) (95% CI) 15.0 (3.0-74.3), p = 0.001; lowest recorded blood glucose ≤1 mmol/L; OR 3.8 (1.3-11.3), p = 0.015, being non-Scandinavian patient, OR 3.8 (1.2-11.9), p = 0.023; and treatment delay from first symptom to expert center >5 days; OR 4.0 (1.0-16.6), trend p = 0.05. In multivariate analysis (n = 31) for early predictors with exclusion of brain MRI, treatment delay from first symptom to expert center >5 days conferred a significantly increased risk of neurodevelopment impairment, adjusted OR (aOR) 15.6 (1.6-146.7), p = 0.016, while lowest blood glucose ≤1 mmol/L had a trend toward increased risk, aOR 3.5 (1.1-14.3), p = 0.058. No associations for early vs. late disease onset, K_ATP-channel mutations, disease severity, focal vs. diffuse disease, or age at follow-up were seen in uni- or multivariate analysis.

CONCLUSION

Not only very low blood glucose, but also insufficient treatment as expressed by delay until expert center hospitalization, increased the risk of neurodevelopmental impairment. This novel finding calls for improvements in spread of knowledge about CHI among health-care personnel and rapid contact with an expert CHI center on suspicion of CHI.

Surgery in congenital hyperinsulinism-tips and tricks not only for surgeons. A practical guide

Each form of congenital hyperinsulinism (CHI)-focal, diffuse, atypical-requires its own surgical strategy and technique. Focal CHI is treated by a positron emission tomography/computed tomography-guided, local resection which is confined only to the lesion. As much healthy pancreatic tissue as possible is preserved. On the contrary, the therapeutic mainstay of diffuse CHI must be conservative nowadays. Only in the exceptional cases in which medical treatment fails surgical therapy is warranted to prevent hypoglycemia. However, the extension of resection that is able to cure hyperinsulinism while avoiding diabetes is not known today. The outcome, therefore, is unpredictable. In the rare atypical cases it is important to stop the resection at the right time in order not to finish unnecessarily with a mutilating operation.

Surgical management of congenital hyperinsulinism of infancy

Congenital hyperinsulinism of infancy (CHI) is characterized by inappropriate insulin secretion resulting in persistent hypoglycemia, which can lead to irreversible severe neurological damage in the infant. Many patients with CHI will respond to medical therapy, but surgery is necessary in those that do not. There are 2 main histologic subtypes, diffuse and focal, both of which may require different surgical strategies. Near-total pancreatectomy is the procedure of choice for diffuse CHI, whereas a localized resection is curative in focal CHI. Open surgery is the traditional approach to pancreatic resection. However, laparoscopy is increasingly used, particularly in localized resection for focal disease. We describe both methods of pancreatectomy.

Persistent hyperinsulinemic hypoglycemia with left ventricular hypertrophy and dysrhythmia: a case report

Persistent hyperinsulinemic hypoglycemia in neonatal period is characterized by insulin hypersecretion. The major feature is severe hypoglycemia, generally unresponsive to routine medical treatment. Subtotal or total pancreatectomy is performed in unresponsive cases. In this case report, we present a newborn with persistent hypoglycemia unresponsive to medical treatment with dysrhythmic left ventricular hypertrophy. The insulin/C-peptide ratio was 58 as a confirmation of diagnosis. Since hypoglycemia persisted after the initial medical treatment, a subtotal pancreatectomy was performed followed by near-total pancreatectomy. A histologic examination revealed diffuse insulin islets. At the 70th post-natal day, death occurred due to heart failure and ventricular dysrhythmia. To our knowledge, severe dysrhythmia and left ventricular hypertrophy in persistent hyperinsulinemic hypoglycemia (PPH) is identified in the patient.

Post-gastric bypass hyperinsulinism with nesidioblastosis: subtotal or total pancreatectomy may be needed to prevent recurrent hypoglycemia

Symptomatic hyperinsulinemic hypoglycemia and pancreatic nesidioblastosis have recently been described in a small series of patients after gastric bypass surgery for morbid obesity. In the limited published reports of patients with this condition, hyperinsulinism and nesidioblastosis have been managed with distal or subtotal pancreatectomy, with the extent of resection guided by calcium angiography. However, nesidioblastosis may involve the pancreas diffusely, and limited pancreatic resections may predispose patients to further hypoglycemic episodes. We have treated two patients with refractory hyperinsulinism and symptomatic hypoglycemia after successful gastric bypass surgery. One patient underwent an approximately 80% pancreatectomy with good results but subsequently experienced recurrent drop attacks and fainting from hyperinsulinism; a completion pancreatectomy via a pancreaticoduodenectomy was then required. A second patient had profound hyperinsulinemic hypoglycemia and was treated successfully with a subtotal (95%) pancreatectomy. Our experience, the third published report of post-gastric bypass nesidioblastosis, suggests that the risk of recurrent symptomatic hyperinsulinism after limited pancreatectomy is significant and relative euglycemia may be achieved with subtotal or total pancreatectomy.

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.

The outcome in Australian children with hyperinsulinism of infancy: early extensive surgery in severe cases lowers risk of diabetes

AIMS

Hyperinsulinism of infancy (HI) is characterized by unregulated insulin secretion in the presence of hypoglycaemia, often resulting in brain damage. Pancreatic resection for control of hypoglycaemia is frequently resisted because of the risk of diabetes mellitus (DM). We investigated retrospectively 62 children with HI from nine Australian treatment centres born between 1972 and 1998, comparing endocrine and neurological outcome in 28 patients receiving medical therapy alone with 34 who required pancreatic resection to control their hypoglycaemia.

METHODS

History, treatment and clinical course were ascertained from file audit and interview. Risk of DM (hazard ratio) attributable to age at surgery (< vs. > or = 100 days at last pancreatectomy) and extent of resection (< vs. > or = 95%) were calculated using Cox proportional hazards regression and categorical variables compared by the chi2-test. Neurological outcome (normal, mild deficit or severe deficit) was derived from the most authoritative source.

RESULTS

Surgically treated patients had a greater birthweight, earlier presentation and higher plasma insulin levels. Of 18 infants < 100 days and 16 > or = 100 days of age at surgery, four (all > or = 100 days) became diabetic as an immediate consequence of surgery and five (two < 100 days and three > or = 100 days) became diabetic 7-18 years later. Surgery > or = 100 days and pancreatectomy > or = 95% were associated with development of diabetes (HR = 12.61, CI 1.53-104.07 and HR = 7.03, CI 1.43-34.58, respectively). Neurodevelopmental outcome was no different between the surgical and medical groups with 44% overall with neurological deficits. Patients euglycaemic within 35 days of the first symptom of hypoglycaemia (Group A) had a better neurodevelopmental outcome than those still hypoglycaemic > 35 days from first presentation (Group B) (P = 0.007). Prolonged hypoglycaemia in Group B was due either to delayed diagnosis or to need for repeat surgery because of continued hypoglycaemia. Within Group A, medically treated patients (who presented later with apparently milder disease) had a higher incidence of neurodevelopmental deficit (n = 15, four mild, three severe deficit) compared with surgically treated patients (n = 18, two mild, none severe deficit) (P < 0.025).

CONCLUSIONS

Poor neurodevelopmental outcome remains a major problem in hyperinsulinism of infancy. Risk of diabetes mellitus with pancreatectomy varies according to age at surgery and extent of resection. Patients presenting early with severe disease have a better neurodevelopmental outcome and lower risk of diabetes if they are treated with early extensive surgery.

Surgical complications of pancreatectomy for persistent hyperinsulinaemic hypoglycaemia of infancy

PURPOSE

The aim of this study was to review the surgical complications of pancreatectomy for persistent hyperinsulinaemic hypoglycaemia of infancy (PHHI).

METHODS

A retrospective review was conducted of patients undergoing pancreatectomy for PHHI in one institution over the past 13 years.

RESULTS

The records of 48 patients were reviewed; the age at operation ranged from 10 days to 30 months (median, 8 weeks). Weight at operation ranged from 1.97 to 11.4 kg (median, 5.2 kg). There were no deaths. Intraoperative complications comprised bleeding in 7, (major in 2), splenic injury in one, bile duct injury in 2 (1 oversewn, 1 choledochoduodenostomy), and 1 small bowel injury. Postoperatively, 5 children underwent choledochoduodenostomy: 2 for biliary leak and 3 for delayed bile duct stricture. Other postoperative complications included wound infection (n = 3), prolonged ileus (n = 1) and adhesion obstruction (n = 1), and wound leakage (n = 1). Renal failure developed in one child owing to acute tubular necrosis. Nine patients required further pancreatic resection because of continued hypoglycaemia. Three patients continued to require medication for hyperinsulinism despite surgery, 20 required insulin, and 13 required pancreatic enzyme replacement at the time of the last review.

CONCLUSIONS

Pancreatectomy resulted in resolution of hyperinsulinism in 45 of 48 patients. Sixteen patients required no further surgery or medication. Pancreatectomy for PHHI may be associated with major intra and postoperative morbidity.

K(ATP) channels and insulin secretion disorders

ATP-sensitive potassium (K(ATP)) channels are inhibited by intracellular ATP and activated by ADP. Nutrient oxidation in beta-cells leads to a rise in [ATP]-to-[ADP] ratios, which in turn leads to reduced K(ATP) channel activity, depolarization, voltage-dependent Ca(2+) channel activation, Ca(2+) entry, and exocytosis. Persistent hyperinsulinemic hypoglycemia of infancy (HI) is a genetic disorder characterized by dysregulated insulin secretion and, although rare, causes severe mental retardation and epilepsy if left untreated. The last five or six years have seen rapid advance in understanding the molecular basis of K(ATP) channel activity and the molecular genetics of HI. In the majority of cases for which a genotype has been uncovered, causal HI mutations are found in one or the other of the two genes, SUR1 and Kir6.2, that encode the K(ATP) channel. This article will review studies that have defined the link between channel activity and defective insulin release and will consider implications for future understanding of the mechanisms of control of insulin secretion in normal and diseased states.

Compound heterozygosity for the common sulfonylurea receptor mutations can cause mild diazoxide-sensitive hyperinsulinism

Persistent hyperinsulinemic hypoglycemia of infancy (PHHI) is a disorder characterized by dysregulation of insulin secretion and prolonged hypoglycemia. Mutations in the genes of both subunits of the beta-cell KATP channel, Kir 6.2 (potassium channel) and SUR1 (sulfonylurea receptor) have been associated with the autosomal recessive form of this disorder. It was previously demonstrated that patients harboring SUR1 mutations often do not respond well to diazoxide. A patient is reported of compound heterozygosity for the 2 most common mutations previously reported to be associated with PHHI in Ashkenazi Jews; splice mutation of intron 32 (3993-9G-->A) and deletion of phenylalanine at position 1388. Relatively low glucose utilization (<10 mg/kg/min) was needed to maintain blood gllucose concentrations. In addition, treatment with diazoxide was highly effective. We suggest that diazoxide unresponsiveness is not always present in patients with SUR1 mutations and that the probable cause of the milder phenotype in this compund heterozygote state

Ten years' experience of persistent hyperinsulinaemic hypoglycaemia of infancy

OBJECTIVE

To review the presentation, management and outcome of persistent hyperinsulinaemic hypoglycaemia of infancy seen at the Royal Alexandra Hospital for Children over a 10 year period.

METHODOLOGY

A retrospective review of 20 subjects was performed. As well as laboratory data, data were collected on clinical presentation, medical and surgical management and developmental outcome.

RESULTS

Twenty subjects (11 male) were identified with presentation at a median age of 1.5 months (range 0-10 months), with 10 (50%) presenting in the first week of life. Only 20% of patients were large for gestational age. Diagnosis was made on the basis of high glucose requirements and inappropriately high insulin levels at the time of hypoglycaemia. Eight (40%) responded well to diazoxide treatment alone, seven (35%) received diazoxide in combination with other short-term medical therapy initially and five (25%) required pancreatectomy (repeat surgery in three). Those who required surgery had a higher mean birth weight. Infants presenting in the first week of life were less likely to respond to diazoxide. At the time of last review, eight (40%) of those treated medically had ceased all treatment. Two of the five cases requiring pancreatectomy now require insulin treatment. Neurodevelopmental assessment was normal in 11 (55%), mild delay was found in six (30%) and moderate or severe delay was found in three (15%).

CONCLUSIONS

Persistent hyperinsulinaemic hypoglycaemia of infancy remains a major diagnostic and management challenge. Early suspicion and recognition is critical with definitive investigation and medical therapy to avoid hypoglycaemia, with pancreatectomy in medically unresponsive cases. Normal neurodevelopmental outcome was found in only 55% of cases.

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.

Persistent hyperinsulinemic hypoglycemia of infancy: long-term outcome following subtotal pancreatectomy

BACKGROUND

Persistent hyperinsulinemic hypoglycemia of infancy (PHHI) is the most common cause of persistent hypoglycemia in infants. The current standard treatment is subtotal pancreatectomy (Px). However, the long-term outcome following surgery needs further attention.

METHODS

We analyzed 10 children (7 M, 3 F) with PHHI who underwent partial (65-80%) and subtotal (81-95%) Px. Follow-up ranged from 2 to 9.4 yr (mean = 4.2 yr). We divided them into 2 groups based upon the age at onset of hypoglycemia: early (< 1 mo) and late (> or = 1 mo).

RESULTS

The seven patients in the early-onset group underwent 85-95% Px between ages of 18 d and 3 mo. Three of them initially treated by 85-90% Px had persistent hypoglycemia postoperatively. Two out of three required a 2nd operation with 95% Px for controlling hypoglycemia, though both still had persistent hypoglycemia and required medication to control blood glucose. The remaining four had 95% Px and had maintained euglycemia postoperatively. One patient developed diabetes 6 yr after surgery. Six of seven patients had delayed development and subnormal IQ. Three patients of the late-onset group (3 mo, 6 mo and 4 yr) underwent partial Px (80%, 65% and 65%, respectively) and maintained euglycemia postoperatively. Despite 65% Px, one developed diabetes 3 yr after surgery.

CONCLUSIONS

These results suggest that children with early-onset hypoglycemia have more severe hyperinsulinism than those with late-onset hypoglycemia. The former require 95% Px for maintaining euglycemia, but long-term complications with diabetes may be common. In contrast, the latter require lower percentage Px which may reduce the incidence of diabetes in the future.

Successful therapy with calcium channel blocker (nifedipine) in persistent neonatal hyperinsulinemic hypoglycemia of infancy

The appropriate management of persistent hyperinsulinemic hypoglycemia of infancy (PHHI) still remains controversial. Some patients show a response to treatment with diazoxide or somatostatin, but a number of children require total or near-total pancreatectomy to control hyperinsulinism. Recent studies suggest a dysfunction in the adenosine triphosphate-sensitive potassium channel present in the plasma membrane of pancreatic beta-cells in PHHI. The closure of these channels initiating the depolarization of the beta-cell membrane and opening of calcium channels results in an increase in intracellular calcium which triggers insulin secretion. A calcium channel blocking agent has been shown to block this process and decrease insulin secretion of the nesidioblastotic beta-cells in vitro and to control the hyperinsulinemic hypoglycemia of the patient in vivo. To examine the efficacy of calcium channel blocker therapy, three patients with PHHI were treated with nifedipine. PHHI was diagnosed by inappropriately high insulin levels for low blood glucose levels at 8-10 days of age. Normoglycemia was maintained by a high dose of glucose infusion at a rate of 14-16 mg/kg/min. Therapy using diazoxide and/or somatostatin analogue failed to restore euglycemia in these three patients. The first patient underwent near-total pancreatectomy; however, hyperinsulinism recurred 30 days after surgery. All patients were started on short acting nifedipine at a dose of 0.3 mg/kg/day per os in four doses. To maintain blood glucose levels in normal ranges, the dose of nifedipine was progressively increased to 0.7-0.8 mg/kg/day. Glucose infusion rate to restore euglycemia decreased and was discontinued on the 4th to 10th day of nifedipine treatment. The patients, who have now been followed on nifedipine therapy for over 12 months, are normoglycemic with normal insulin levels. The growth and neuromotor development of the patients are unremarkable except for mild developmental delay of the patient who underwent near-total pancreatectomy. No side effects were encountered at the doses used. In conclusion, calcium channel blocking agents can be used with efficacy and safety in PHHI to control the hyperinsulinemia.

Congenital hyperinsulinism and the surgeon: lessons learned over 35 years

BACKGROUND/PURPOSE

Congenital hyperinsulinism induces severe and unremitting hypoglycemia in newborns and infants. If poorly controlled, seizures and irreversible brain damage may result. Subtotal (<95%) or near-total (95% to 98%) pancreatectomy have been performed for glycemic control in babies who do not respond to aggressive medical therapy. Because hypoglycemia often persists after subtotal resection, 95% pancreatectomy has emerged as the procedure of choice. To define the effect of more or less extensive pancreatectomy on the management and outcome of refractory congenital hyperinsulinism, the authors examined our single institutional experience.

METHODS

The records of children treated between 1963 and 1998 for congenital hyperinsulinism, and who required pancreatectomy, were reviewed. Outcome parameters included glycemic response to surgery, need for reresection, surgical morbidity, surgical and long-term mortality, and development of diabetes mellitus (DM). A complete response was defined as discharge to home on no glycemic medications, no continuous feedings, and without DM. Histological reports were reviewed and categorized as either diffuse or focal disease.

RESULTS

Of 101 children treated for congenital hyperinsulinism during this period, 53 (50%) required pancreatectomy for glucose control. Mean follow-up for the study population was 9.8 +/- 1.1 years. Overall, 23 children (43%) showed a complete response, occurring in 50% of patients having > or = 95% pancreatectomy (n = 34), but in only 19% having less than 95% resection (n = 16). The remaining three babies had local excision of a solitary focal lesion, and each showed a complete response. Histopathology showed diffuse islet abnormalities in 42 specimens (79%) and solitary focal lesions in 11 (21%). A complete response was observed for 82% of focal but only 33% of diffuse lesions. Eight patients (15%) required reresection for persistent hypoglycemia, seven having diffuse lesions and one focal. Surgical morbidity occurred in 13 cases (26%), and the 30-day surgical mortality rate was 6%, each death (n = 3) occurring before 1975. DM developed in seven children (14%), each having diffuse lesions, and was independent of resection type.

CONCLUSION

Because euglycemia is more readily restored, and because the risks for surgical complications and DM do not appear increased, the authors recommend 95% pancreatectomy as the initial procedure of choice for newborns and infants with congenital hyperinsulinism.

Clinical features of 52 neonates with hyperinsulinism

BACKGROUND

Neonatal hyperinsulinemic hypoglycemia is often resistant to medical therapy and is often treated with near-total pancreatectomy. However, the pancreatic lesions may be focal and treatable by partial pancreatic resection.

METHODS

We studied 52 neonates with hyperinsulinism who were treated surgically. The type and location of the pancreatic lesions were determined by preoperative pancreatic catheterization and intraoperative histologic studies. Partial pancreatectomy was performed in infants with focal lesions, and near-total pancreatectomy was performed in those with diffuse lesions. The postoperative outcome was determined by measurements of plasma glucose and glycosylated hemoglobin and by oral glucose-tolerance tests.

RESULTS

Thirty neonates had diffuse beta-cell hyperfunction, and 22 had focal adenomatous islet-cell hyperplasia. Among the latter, the lesions were in the head of the pancreas in nine, the isthmus in three, the body in eight, and the tail in two. The clinical manifestations were similar in both groups. The infants with focal lesions had no symptoms of hypoglycemia and had normal preprandial and postprandial plasma glucose and glycosylated hemoglobin values and normal results on oral glucose-tolerance tests after partial pancreatectomy (performed in 19 of 22 neonates). By contrast, after near-total pancreatectomy, 13 of the patients with diffuse lesions had persistent hypoglycemia, type 1 diabetes mellitus developed in 8, and hyperglycemia developed in another 7; overall, only 2 patients with diffuse lesions had normal plasma glucose concentrations in the first year after surgery.

CONCLUSIONS

Among neonates with hyperinsulinism, about half may have focal islet-cell hyperplasia that can be treated with partial pancreatectomy. These neonates can be identified through pancreatic catheterization and intraoperative histologic studies.

Persistent hyperinsulinemic hypoglycemia of infancy: long-term results

Data from 15 infants with persistent hyperinsulinemic hypoglycemia of infancy (PHHI), presented to our hospital from 1976 to 1995, were retrospectively analyzed. Nine patients were successfully managed with prolonged (1.25-13 yr) diazoxide therapy and frequent, low protein feeds. Three of them are still being treated with diazoxide, 7.75, 9.25 and 13 yr post diagnosis. Four patients were managed only with frequent, low protein feeds. One patient had 2/3 pancreatectomy, and another had excision of a focal lesion which proved to be focal nesidioblastosis. Two patients were lost to follow up. No patient has shown neurological damage. One girl developed seizures at age 11.5 yr without hypoglycemia. The patient with 2/3 pancreatectomy developed diabetes mellitus at the age of 20 years. Although conservative management of PHHI is very laborious for the family and the physician, it should be applied as long as euglycemia is accomplished. Definition of the anatomical lesion (focal or diffuse) prior to pancreatectomy is recommended.

Therapy for persistent hyperinsulinemic hypoglycemia of infancy. Understanding the responsiveness of beta cells to diazoxide and somatostatin

The neonatal disorder persistent hyperinsulinemic hypoglycemia of infancy (PHHI) arises as the result of mutations in the subunits that form the ATP-sensitive potassium (KATP) channel in pancreatic beta cells, leading to insulin hypersecretion. Diazoxide (a specific KATP channel agonist in normal beta cells) and somatostatin (octreotide) are the mainstay of medical treatment for the condition. To investigate the mechanism of action of these agents in PHHI beta cells that lack KATP currents, we applied patch clamp techniques to insulin-secreting cells isolated from seven patients with PHHI. Five patients showed favorable responses to medical therapy, and two were refractory. Our data reveal, in drug-responsive patients, that a novel ion channel is modulated by diazoxide and somatostatin, leading to termination of the spontaneous electrical events that underlie insulin hypersecretion. The drug-resistant patients, both of whom carried a mutation in one of the genes that encode KATP channel subunits, also lacked this novel K+ channel. There were no effects of diazoxide and somatostatin on beta cell function in vitro. These findings elucidate for the first time the mechanisms of action of diazoxide and somatostatin in infants with PHHI in whom KATP channels are absent, and provide a rationale for development of new therapeutic opportunities by K+ channel manipulation in PHHI treatment.

Multiple insulinomas of the pancreas: a patient report

Whereas there is general agreement about the biochemical diagnosis of hyperinsulinism, the value of imaging to differentiate diffuse from focal pancreatic lesions is still a matter of debate. We describe a case of multiple adenomas of the pancreas in an eleven year-old boy. The source of hyperinsulinism was detected by pancreatic ultrasound examination and confirmed by MRI as a single adenoma of the pancreas. These radiological exams did not identify three other pancreatic adenomata. Our report outlines the difficulties in anatomically localizing the source of excessive insulin secretion in cases of hyperinsulinemic hypoglycemia.

Is 95% pancreatectomy the procedure of choice for treatment of persistent hyperinsulinemic hypoglycemia of the neonate?

A 95% pancreatectomy became the treatment of choice for persistent hyperinsulinemic hypoglycemia of the neonate (PHHN, Nesidioblastosis) at the author's institution, when lesser resections failed to prevent hypoglycemia in 25% to 50% of cases. With few outcome data available in the literature, the authors reviewed their 25-year experience to assess the efficacy and the long-term consequences of this procedure. Since 1971, 27 infants underwent a 95% pancreatectomy for the treatment of PHHN. None had responded to medical treatment (glucose infusion, glucagon, octreotide, diazoxide), and two had 85% pancreatectomy that failed. The procedure consisted of resecting the pancreas including the uncinate process, leaving only the gland lying between the common bile duct (CBD) and the duodenum and a small rim of pancreas along the duodenal sweep. Hyperinsulinemia and hypoglycemia recurred in nine children (33%), all within 2 to 5 days. Seven of them were subsequently cured with near-total pancreatic resection. Partial pancreatic regrowth was evident at reoperation. In two cases hypoglycemia was controlled with diazoxide and frequent feedings because reoperation was refused. The gross anatomic findings and the histopathology were not predictive of treatment failure. Perioperative complications occurred in four of 27 children (15%) after 95% pancreatectomy and in four of seven children (57%) after near-total pancreatectomy. Clinical follow-up ranged from 0.5 to 18 years (mean, 8 years; median, 8 years). To date, diabetes has developed in 15 children (56%), nine of 20 (45%) after 95% pancreatectomy (mean age, 9.7 years) and six of seven (86%) after a near-total pancreatectomy (mean age, 1.7 years). After 95% pancreatectomy, the incidence of diabetes increased with age, developing in nine of the 13 (69%) children followed up for more than 4 years. The failure of 95% pancreatectomy to prevent hypoglycemia in one third of children with PHHN and the ultimate development of diabetes in a minimum of two-thirds, indicates that an alternative treatment strategy is needed for this disease.

Loss of functional KATP channels in pancreatic beta-cells causes persistent hyperinsulinemic hypoglycemia of infancy

Persistent hyperinsulinemic hypoglycemia of infancy (PHHI) is a disorder of childhood associated with inappropriate hypersecretion of insulin by the pancreas. The pathogenesis of the condition has hitherto remained controversial. We show here that insulin-secreting cells from a homogeneous group of five infants with PHHI lack ATP-sensitive K+ channel (KATP) activity. As a consequence, PHHI beta-cells are spontaneously electrically active with high basal cytosolic Ca2+ concentrations due to Ca2+ influx. Our findings define the pathogenesis of this disease as a novel K+ channel disorder.

Ionic control of beta cell function in nesidioblastosis. A possible therapeutic role for calcium channel blockade

A preterm female infant presented with intractable hypoglycaemia within 10 minutes of delivery. Normoglycaemia could be maintained only by the intravenous infusion of glucose at a rate of 20-22 mg/kg/min. Persistent hyperinsulinaemic hypoglycaemia of infancy was diagnosed from an inappropriately raised plasma insulin concentration (33 mU/l) at the time of hypoglycaemia (blood glucose < 0.5 mmol/l). Medical treatment with glucagon, somatostatin, and diazoxide led to only a modest reduction in the intravenous glucose requirement; a 95% pancreatectomy was performed and histological 'nesidioblastosis' confirmed. In vitro electrophysiological studies using patch clamp techniques on isolated pancreatic beta cells characterised the ionic basis for insulin secretion in nesidioblastosis. The beta cells were depolarised in low ambient glucose concentrations with persistently firing action potentials; these were blocked reversibly by the calcium channel blocking agent verapamil. Persistent postoperative hyperinsulinaemic hypoglycaemia was treated with oral nifedipine. This increased median blood glucose concentrations from 3.5 to 4.8 mmol/l and increased in duration the child's tolerance to fasting from 3 to 10.5 hours. These data allude to an abnormality in the ionic control of insulin release in nesidioblastosis and offer a new logical approach to treatment which requires further evaluation.

Growth and endocrine function after near total pancreatectomy for hyperinsulinaemic hypoglycaemia

Seven children, with a mean (SD) age of 4.6 (2.1) years, who as infants (21 (7.5) days) underwent near total (95-98%) pancreatectomy for persistent hyperinsulinaemic hypoglycaemia of infancy (PHHI) were studied. At birth all the infants were macrosomic. Four infants had been born after a difficult labour, of whom three had moderate birth asphyxia and respiratory distress. All had normal thyroid function. After surgery transient hyperglycaemia was manifest in six of the children and required insulin treatment for 5.8 (3.8) weeks, and transient hypoglycaemia was encountered in one child and responded well to increased carbohydrate intake and diazoxide for three weeks. Six of the children rapidly crossed down their length and weight centiles during the first year after surgery. At the end of the first year these children were at or below the 5th centile of height and weight for their age and gender. After a period of 4.6 (2.1) years, their mean (SD) height score was -2.57 (0.5), growth velocity 3.9 (0.75) cm/year, and growth velocity SD score -2.1 (0.55)l these were significantly low and denoted significant growth retardation. The growth hormone peak responses to provocation with clonidine were normal (13.5 (2.8) micrograms/l). However, the circulating insulin-like growth factor-I (IGF-I) concentrations were significantly decreased (79 (34) ng/ml). Three of the children developed diabetes at two and a half, five, and seven years after surgery, two others had impaired oral glucose tolerance and six out of the seven children had an impaired C peptide response to glucagon. Defective insulin secretion in these children might directly inhibit IGF-I synthesis in the liver. The body mass index of the pancreatectomised children was 14.9 (0.5) and was normal for age and gender; they had a normal 72 hour faecal fat content and normal serum albumin concentration. These data indicated grossly adequate exocrine pancreatic function. It appears that children requiring near total pancreatectomy for PHHI have normal developmental milestones but defective linear growth with impaired insulin secretion and low IGF-I production despite normal growth hormone response to provocation.

Anaesthetic management of a neonate with nesidioblastosis

Nesidioblastosis is a disorder which is characterized by autonomous insulin secretion that is not affected by decreases in blood glucose. Patients usually present during the neonatal or infantile period with hypoglycaemia associated with hyperinsulinaemia. Most cases of nesidioblastosis are sporadic; however, familial forms appears to be inherited in an autosomal recessive manner. We discuss the anaesthetic management of a patient with nesidioblastosis who presented for near total pancreatectomy and review the literature pertinent to the anaesthesiologist.

Gestational diabetes mellitus and paradoxical fetal macrosomia--a case report

Gestational diabetes mellitus (GDM) is associated with an increased rate of fetal macrosomia. We describe the outcome of two pregnancies complicated by GDM occurring 2 years apart in a normal-weight woman. Despite adequate maternal blood glucose control during gestation, both infants were markedly oversized at birth (birth weight and length exceeded normal means by 3 and 2 S.D., respectively). The placental weights were far above normal. At birth, the siblings shared the typical appearance of a diabetes fetopathy. The first one developed transient, the second persistent neonatal hypoglycemia associated with hyperinsulinemia, that needed treatment with diazoxide for 2.5 months. Both infants normalized their growth rates during the following months; their psychomotor development assessed at 2 years and at 9 months of age, respectively, was normal. During the last trimester of the second pregnancy, the plasma concentration of placental lactogen (PL) increased to a very high level (19 micrograms/l). The maternal early insulin response to glucose increased significantly with gestation and was much above that in the non-pregnant state. This rise in insulin response could not compensate for the concomitant decrease in insulin sensitivity as assessed by the minimal model according to Bergman [2]. The pronounced fetal macrosomia described cannot be attributed to GDM only. We speculate that excess activity of lactogenic hormones like PL beside glucose contribute to exaggerated fetal beta-cell function with growth acceleration and neonatal hypoglycemia. This hypothesis is in accordance with in vitro evidence indicating that PL may have an important role in the regulation of the maternal and fetal beta-cell mass and function.

A mild case of nesidioblastosis with diagnostic and therapeutic difficulty

A female infant with nesidioblastosis who showed mild clinical symptoms is reported. In this patient, insulin levels and insulin to glucose ratios (IRI/G) were often normal. Regular milk feedings supplemented with continuous glucose infusion (0.7-2 mg/kg per min) or oral glucose feedings (4.5 mg/kg per min) prevented hypoglycemia. As leucine-sensitivity was diagnosed at 2 months of age, she was started on diazoxide. This was, however, ineffective, and adverse effects appeared. Subtotal pancreatectomy (95%) was therefore attempted at 5 months of age, and persistent normoglycemia as well as normal growth and development followed up to 3 years after the operation. The pancreas showed characteristic signs of nesidioblastosis. The above clinical observation suggests that a patient with nesidioblastosis whose blood glucose level is easily controllable may develop an unexpected episode of hypoglycemia in the presence of a leucine sensitivity. In such a patient, diazoxide or, when it is of no avail, surgical intervention should promptly be instituted to prevent possible neurologic sequelae induced by hypoglycemia.