Familial hyperinsulinism: successful conservative management

Glucose Homeostasis in Newborns: An Endocrinology Perspective

Physiologic adaptations in the postnatal period, along with gradual establishment of enteral feeding, help maintain plasma glucose concentrations in the neonatal period. The definition of normal plasma glucose in the neonatal period has been a subject of debate because of a lack of evidence linking a set plasma or blood glucose concentration to clinical symptoms or predictors of short- and long-term outcomes. However, there is consensus that maintaining plasma glucose in the normal range for age is important to prevent immediate and long-term neurodevelopmental consequences of hypoglycemia or hyperglycemia. The specific management strategy for abnormal glucose levels in neonates depends on the underlying etiology, and interventions could include nutritional changes, medications, hormone therapy, or even surgery. Here, we will review the physiological processes that help maintain plasma glucose in newborns and discuss the approach to a newborn with disordered glucose homeostasis, with an emphasis on the endocrine basis of abnormal glucose homeostasis.

Management strategies for neonatal hypoglycemia

While hypoglycemia occurs commonly among neonates, treatment can be challenging if hypoglycemia persists beyond the first few days of life. This review discusses the available treatment options for both transient and persistent neonatal hypoglycemia. These treatment options include dextrose infusions, glucagon, glucocorticoids, diazoxide, octreotide, and nifedipine. A stepwise, practical approach to the management of these patients is offered.

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.

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.

When it is more than transient neonatal hypoglycemia: hyperinsulinemia--a case study challenge

Persistent uncontrolled neonatal hypoglycemia may cause irreversible brain damage. Hyperinsulinemia is a rare cause of persistent hypoglycemia, diagnosed by excluding other etiologies. Inappropriately high fasting serum insulin levels with concurrent hypoglycemia confirm the diagnosis. Initial interventions for hyperinsulinemia are conservative. The first line of therapy is administration of adequate intravenous (i.v.) glucose to maintain serum or whole blood glucose levels at or greater than 40 mg/dl. When enteral feedings are tolerated, schedules and caloric concentration are adjusted. Pharmacologic therapy is added to facilitate weaning from i.v. glucose. The drug of first choice is diazoxide. Octreotide is added if diazoxide therapy fails. Partial or complete pancreatectomy is the final treatment option. Nursing care for infants with hyperinsulinemia must also focus on the support and education of families. Family education must be individualized and should cover feeding regimes, administration of medication, proper use of equipment, and care during illness.

Genetics of neonatal hyperinsulinism

Congenital hyperinsulinism (HI) is a clinically and genetically heterogeneous entity. The clinical heterogeneity is manifested by severity ranging from extremely severe, life threatening disease to very mild clinical symptoms, which may even be difficult to identify. Furthermore, clinical responsiveness to medical and surgical management is extremely variable. Recent discoveries have begun to clarify the molecular aetiology of this disease and thus the mechanisms responsible for this clinical heterogeneity are becoming more clear. Mutations in 4 different genes have been identified in patients with this clinical syndrome. Most cases are caused by mutations in either of the 2 subunits of the beta cell ATP sensitive K(+) channel (K(ATP)), whereas others are caused by mutations in the beta cell enzymes glucokinase and glutamate dehydrogenase. However, for as many as 50% of the cases, no genetic aetiology has yet been determined. The study of the genetics of this disease has provided important new information about beta cell physiology. Although the clinical ramifications of these findings are still limited, in some situations genetic studies might greatly aid in patient management.

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.

Neonatal Hyperinsulinism

Hypoglycemia as a result of hyperinsulinism in the newborn (HI) is a clinically heterogeneous entity that presents a diagnostic and therapeutic challenge to the treating physician. Recent discoveries have shown that mutations in four different beta-cell genes cause HI. However, for many HI patients, the molecular etiology is unknown, and other genes might be involved. The study of the molecular biology of HI has led to a better understanding of pancreatic beta-cell physiology. In the future, this might result in the development of novel drugs for the treatment of both hyperinsulinism and non-insulin-dependent diabetes.

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

AIM

To evaluate long term detailed pancreatic endocrine and exocrine function in children with persistent hyperinsulinaemic hypoglycaemia of infancy (PHHI) after 85-95% pancreatectomy.

METHODS

Six children with PHHI between 0.9 and 12.7 years after pancreatic resection underwent clinical and investigative follow up at 1.0 to 14.9 years of age. One child with PHHI who had not had pancreatectomy was also assessed. Standard endocrine assessment, pancreatic magnetic resonance imaging (MRI), and detailed direct and indirect tests of exocrine pancreatic function were performed.

RESULTS

Pancreozymin-secretin stimulation test results were normal in only one child, borderline in two, and deficient in four, one of whom requires daily pancreatic enzyme supplements. Pancreolauryl tests performed in three children were borderline in two and abnormal in the other. Only one child had low faecal chymotrypsin values. One child developed insulin dependent diabetes at 9 years and two children at 1.0 and 13.3 years require diazoxide to maintain normoglycaemia. MRI showed no major regrowth of the pancreatic remnant after resection (n = 5).

CONCLUSIONS

Clinical evidence of endocrine or exocrine dysfunction has developed in only two patients to date, but detailed pancreatic function testing suggests subclinical deficiency in all but one of our patients with PHHI. Although 95% pancreatectomy results in postoperative control of blood glucose, subclinical pancreatic insufficiency is present on long term follow up and development of diabetes mellitus and exocrine failure remain ongoing risks.

Neonatal hyperinsulinemic hypoglycemia: heterogeneity of the syndrome and keys for differential diagnosis

The two major forms of infantile persistent hyperinsulinemic hypoglycemia require different treatments, but are difficult to differentiate during surgery. Indeed, one is characterized by focal adenomatous hyperplasia often macroscopically invisible, whereas the other consists of a diffuse, but discreet, beta-cell abnormality. We evaluated, in a large series of persistent hyperinsulinemic hypoglycemia, the reliability of two criteria in differentiating these two forms: the mean beta-cell nuclear radius (MNR) and the beta-cell nuclear crowding, i.e. the number of nuclei per 1000 micron 2 beta-cell (BCNC). The values of the largest MNR and of BCNC in cases bearing a focal lesion (respectively, 3.27 microns +/- 0.25 and 14.62 +/- 1.78) were significantly different from those in the diffuse pathology (4.25 microns +/- 0.43 and 10.00 +/- 1.55). Setting the threshold value of MNR at 3.70 microns and that of BCNC at 12.00 enabled correct classification of 90.9% of the diffuse and 100% of the focal forms. beta-Cell nuclear analysis can thus contribute to a subclassification of the syndrome, not allowed by clinical or biological data. If performed during surgery it could help in determining the extent of pancreatectomy necessary to cure the patient, as the diffuse form, with abnormal nuclei in the whole pancreas, requires subtotal to near-total pancreatectomy, whereas the focal form, devoid of abnormal insular beta-cell nuclei, can be cured by partial pancreatectomy.

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.

Prospective study of nesidioblastosis in newborns and infants: hypoglycemic seizures, epileptogenesis and the significance of the C-peptide suppression test in pancreatectomy

The long-term follow-up of chronic hyperinsulinemic seizures, epileptogenesis and other neurological complications in five patients who were treated with conservative therapy followed by pancreatectomy during the neonatal period and infancy, who were confirmed to have diffuse nesidioblastosis are described. The reaction pattern of the C-peptide (CPR) suppression test and its relation to the final extent of pancreatectomy was examined in four patients. The chronological change in electro-encephalography (EEG) and its epileptogenesis was also examined in each patient during hyperinsulinemic hypoglycemia, and during normoglycemia in a long-term post-pancreatectomy follow-up. All patients demonstrated several types of hypoglycemic seizures, ranging from apnea, erratic seizures, evolving to generalized/unilateral tonic-clonic or tonic seizures, myoclonic seizures and EEG abnormalities. Four of five patients still suffered from epilepsy at the age of 4-22 years. The reaction pattern of the CPR suppression test showed dichotomy, with a hyper-reactive pattern in two patients who required total pancreatectomy to control hypoglycemia, and a suppression pattern in two other patients treated with 90-95% pancreatectomy. Neonatal onset and subsequent myoclonic seizures were ominous signs of epileptogenesis to various types of intractable epilepsy and other neurological sequelae. A prompt diagnosis and pancreatectomy of a sufficient extent at the first operation are essential. The CPR suppression test may be useful for a prompt diagnosis and selection of the extent of pancreatectomy.

Different neurologic outcomes in two patients with neonatal hyperinsulinemic hypoglycemia

The authors report the cases of two patients with neonatal onset of hypoketotic hypoglycemia with hyperinsulinism and a poor response to diazoxide. Pancreatic venous sampling showed a diffuse pancreatic hyperplasia in one patient and a focal lesion in the other. The second patient, diagnosed after a significant delay, suffered severe long-term neurological sequelae, despite having more limited hyperplasia; the brain MRI also showed severe pathological changes in cortex and white matter, predominantly in the parieto-occipital region. Early and accurate diagnosis is critical in these patients in whom hypoglycemia is compounded by a lack of the ketone bodies which represent a vital alternative source of energy for the central nervous system.

Savant characteristics in a child with developmental delay and deletion in the short arm of chromosome 20

The development outcome of a four-year-old boy with a deletion of the short arm of chromosome 20 is described. Despite a number of early medical problems, including infantile hypoglycemic convulsions secondary to growth hormone deficiency and delayed motor and language development, he has been reading (self-taught) since 2.5 years and currently has computer proficiency, and exceptional memory for maps and spatial locations, an extremely rich and active fantasy life, good diction, and an extensive spoken vocabulary. Neuropsychological evaluation revealed low-average intelligence with normal language, memory and attention functions, and impaired visuomotor and graphomotor ability and motor skills. He showed extremely advanced decoding and reading comprehension skills while mathematics, spelling and general knowledge abilities were average.

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.

Persistent hyperinsulinemic hypoglycemia of infancy: long-term octreotide treatment without pancreatectomy

Eight patients with persistent hyperinsulinemic hypoglycemia of infancy who were treated with octreotide without pancreatectomy are described. All had severe, early-onset disease that would have required partial pancreatectomy had octreotide not been available. Along with octreotide, frequent feedings and raw cornstarch at night were required by all. Octreotide was given in three or four daily subcutaneous injections in four patients and in a continuous subcutaneous infusion with an insulin infusion pump in four. All had mild, transient gastrointestinal symptoms (vomiting, abdominal distention, steatorrhea) after the start of therapy. Asymptomatic gallstones were found in 1 patient after 1 year of treatment. No other long-term untoward effects were noted, including no detrimental effect on psychomotor development. Growth was not affected in five of six patients treated for more than 6 months. In five patients, octreotide was discontinued after 9 months to 5 1/2 years; patients were given diazoxide instead, two required percutaneous gastrostomy, and one 5 1/2-year-old child required no further treatment. The remaining three patients (aged 5 to 9 months) are still being treated with octreotide. We conclude that, with the use of octreotide, pancreatectomy can be avoided in some patients. Particularly in light of our findings of a high incidence of diabetes years after partial pancreatectomy, and clinical improvement after months to years of octreotide treatment, we believe that aggressive medical therapy, when effective, is preferable to partial pancreatectomy.

Familial and sporadic hyperinsulinism: histopathologic findings and segregation analysis support a single autosomal recessive disorder

We evaluated the possible genetic contribution to hyperinsulinism in a series of patients seen during the past 15 years. Of 26 families, 5 (19%) had more than one child affected (multiplex family). There were no apparent differences between patients in the 5 multiplex and 21 simplex families, clinically, biochemically, or on histologic examination of the pancreatic specimens. The families studied had a total of 63 offspring; the 26 index patients had 37 siblings, 6 of whom were affected. After four patients with hyperinsulinism caused by adenoma were excluded from the study, segregation analysis was carried out to test the data for agreement with results expected if familial and isolated hyperinsulinism represented a single disease with recessive mode of inheritance and a segregation ratio of 0.25. Excellent agreement was found between the observed number of affected siblings (20) and the expected number (19.65), with a segregation ratio of 0.254. The results were consistent with the hypothesis that in most or all cases, hyperinsulinism is inherited as an autosomal recessive disease. There was no evidence of distinct familial and sporadic types.