Congenital hyperinsulinism: diagnostic and management challenges in a developing country - case report

PET/CT in congenital hyperinsulinism: transforming patient's lives by molecular hybrid imaging

Congenital hyperinsulinism (HI) is a life-threatening condition characterized by severe and recurrent episodes of hypoglycaemia due to defects in key genes involved in regulating insulin secretion. The delay in diagnosis and inappropriate management of HI lead to high risk of permanent hypoglycemic brain injury. The management of HI is challenging as each form of HI (focal, diffuse, and atypical) requires its own therapeutic strategy. In HI diagnostic work-up, integrated PET/CT scan is currently the first-line imaging technique allowing to differentiate between diffuse and focal form and, in the latter case, to localize the focus within the pancreas with high precision. Only in focal HI partial pancreatectomy is the treatment of choice and a curative surgical treatment means a real chance of transforming patient's lives and HI patient's future. The aim of this review is to discuss the role of PET/CT imaging in HI scenario, its technical advantages and limitations and how successful surgery is strongly dependent on accurate preoperative assessment (genetic analysis and PET/CT scan). A multidisciplinary approach in HI diagnosis and treatment inside a single team (involving different expertise) allows to manage children safely and properly, supporting their families in an organized care network.

Somatostatin analogues for the treatment of hyperinsulinaemic hypoglycaemia

Hyperinsulinaemic hypoglycaemia (HH) is a biochemical finding of low blood glucose levels due to the dysregulation of insulin secretion from pancreatic β-cells. Under normal physiological conditions, glucose metabolism is coupled to β-cell insulin secretion so that blood glucose levels are maintained within the physiological range of 3.5-5.5 mmol/L. However, in HH this coupling of glucose metabolism to insulin secretion is perturbed so that insulin secretion becomes unregulated. HH typically occurs in the neonatal, infancy and childhood periods and can be due to many different causes. Adults can also present with HH but the causes in adults tend to be different. Somatostatin (SST) is a peptide hormone that is released by the delta cells (δ-cells) in the pancreas. It binds to G protein-coupled SST receptors to regulate a variety of location-specific and selective functions such as hormone inhibition, neurotransmission and cell proliferation. SST plays a potent role in the regulation of both insulin and glucagon secretion in response to changes in glucose levels by negative feedback mechanism. The half-life of SST is only 1-3 min due to quick degradation by peptidases in plasma and tissues. Thus, a direct continuous intravenous or subcutaneous infusion is required to achieve the therapeutic effect. These limitations prompted the discovery of SST analogues such as octreotide and lanreotide, which have longer half-lives and therefore can be administered as injections. SST analogues are used to treat different forms of HH in children and adults and therapeutic effect is achieved by suppressing insulin secretion from pancreatic β-cells by complex mechanisms. These treatments are associated with several side effects, especially in the newborn period, with necrotizing enterocolitis being the most serious side effect and hence SS analogues should be used with extreme caution in this age group.

Hyperinsulinism hyperammonaemia (HI/HA) syndrome due to GLUD1 mutation: phenotypic variations ranging from late presentation to spontaneous resolution

Background The hyperinsulinism/hyperammonaemia (HI/HA) syndrome is the second most common cause of hyperinsulinaemic hypoglycaemia, caused by activating mutations in GLUD1. In this article, we report a series of three unrelated patients with HI/HA syndrome who demonstrated variable phenotypes, ranging from delayed presentation to spontaneous resolution of hypoglycaemia, thereby expanding the current knowledge and understanding of GLUD1 mutations. Case presentation This paper is a retrospective analysis of patients with HI/HA syndrome who demonstrated a variable disease course. Patient 1 presented with hypoglycaemic seizures at the age of 7 months and was diagnosed with HI/HA syndrome. Patient 2, a 5-year-old boy, on anti-convulsants since 8 months of age, was diagnosed with HI/HA at the age of 4 years. Patient 3, an 11-year-old girl with a history of transient neonatal hypoglycaemia, was diagnosed with HI/HA at the age of 12 months following evaluation for absence seizures. Patients 1 and 2 had raised ammonia levels, whilst patient 3 had normal ammonia level. The genetic analysis in all three patients confirmed GLUD1 mutation. Good glycaemic control was observed in all following diazoxide treatment. All patients have learning difficulties. Patient 1 demonstrated spontaneous resolution of hypoglycaemia at the age of 8 years, enabling discontinuation of diazoxide. Conclusions The cases highlight the diagnostic challenges in HI/HA syndrome due to a highly variable presentation. Knowledge of variable phenotypes would enable early diagnosis, thereby decreasing the risk of long-term neurological damage. Spontaneous resolution of hyperinsulinism could occur, and it is important to consider a trial off diazoxide therapy especially if the patients are on a small dose of diazoxide.