1/64. hyperinsulinism: molecular aetiology of focal disease.Persistent hypoglycaemia in infancy is most commonly caused by hyperinsulinism. A case is reported of the somatic loss of the maternal 11p in an insulin secreting focal adenoma in association with a germline SUR-1 mutation on the paternal allele in a baby boy with hyperinsulinism diagnosed at 49 days old. A reduction to homozygosity of an SUR-1 mutation is proposed as a critical part of the cause of focal hyperinsulinism.- - - - - - - - - - ranking = 1keywords = hypoglycaemia (Clic here for more details about this article) |
2/64. Clinical presentation of PCOS following development of an insulinoma: case report.A 24 year old woman presented with a prolonged clinical history of fasting and exertional hypoglycaemia, and was subsequently diagnosed with an insulinoma. Concurrent symptoms of oligomenorrhoea and hyperandrogenism of similar duration were noted. Biochemically, hyperinsulinaemia was observed in association with a raised serum luteinizing hormone (LH), raised testosterone and androstendione concentrations. Surgical removal of the insulinoma resulted in resolution of the clinical and biochemical features of the polycystic ovarian syndrome (PCOS) but minimal change was observed in the ovarian ultrasound appearances. This case demonstrates the role of insulin in mediating the hypersecretion of both LH and androgens in women with polycystic ovaries. We suggest that hyperinsulinaemia converted occult 'polycystic ovaries' to become clinically manifest as 'polycystic ovary syndrome'. This paradigm has clear implications for women with insulin dependent diabetes mellitus who presumably have systemic hyperinsulinaemia.- - - - - - - - - - ranking = 1keywords = hypoglycaemia (Clic here for more details about this article) |
3/64. Incidental adult nesidioblastosis after distal pancreatectomy for endocrine microadenoma.Persistent hyperinsulinaemic hypoglycaemia (nesidioblastosis) presenting with hypoglycaemia is extremely rare in adults. The features are suggestive of an insulinoma with a vague presentation and delayed diagnosis. We describe a report of adult nesidioblastosis in association with a pancreatic endocrine microadenoma.- - - - - - - - - - ranking = 2keywords = hypoglycaemia (Clic here for more details about this article) |
4/64. Lessons to be learned: a case study approach insulinoma presenting as a change in personality.A 43-year-old man presented with attacks of altered behaviour over a short period of time; they were associated with episodes of hypoglycaemia. The clinical suspicion of insulinoma prompted investigations that quickly established serum insulin and c-peptide levels to be elevated at the times when blood glucose values were low. A physical lesion was found in the head of the pancreas by means of computerised tomography and endo-duodenal ultrasound scan; an octreotide scan was negative. The patient underwent laparotomy and enucleation of a benign tumour, measuring 2.6 cm in diameter, lying within the head of the pancreas; histological examination confirmed it to be an insulinoma. Postoperatively, the patient's personality gradually became more normal and his fasting blood glucose concentrations returned to within normal limits. The diagnosis and management of insulinoma are discussed in the context of this clinical case; there is also reference to the protean clinical manifestations that may occur in this condition- and its differential diagnosis.- - - - - - - - - - ranking = 1keywords = hypoglycaemia (Clic here for more details about this article) |
5/64. A rare cause of syncope in a patient with diabetes mellitus--a case report.INTRODUCTION: Hypoglycaemic episodes in patients with diabetes mellitus are mostly due to excess doses of exogenous insulin or oral hypoglycaemic agents, coupled with poor caloric intake and excessive unplanned physical exertion. Hypoglycaemia as a result of endogenous hyperinsulinaemia due to an insulinoma is extremely rare in such patients. CLINICAL PICTURE: This patient with type 2 diabetes mellitus presented with episodes of syncope. Investigations confirmed recurrent hypoglycaemia from endogenous hyperinsulinaemia, with localisation of a tumour in the tail of the pancreas. TREATMENT: Distal pancreatectomy and splenectomy. histology confirmed an insulinoma. OUTCOME: No further hypoglycaemic episodes were noted. The patient returned to his diabetic state with rather poor glycaemic control. CONCLUSIONS: Repeated hypoglycaemic episodes in a patient with diabetes mellitus despite complete withdrawal of hypoglycaemic agents should lead one to consider other causes of hypoglycaemia.- - - - - - - - - - ranking = 2keywords = hypoglycaemia (Clic here for more details about this article) |
6/64. Modified hyperinsulinaemic, eu- and hypoglycaemic clamp technique using lispro-insulin for insulinoma diagnostic.Summary:Characterization of metabolically inadequate insulin secretion is essential for insulinoma diagnostics. Hyperinsulinaemic, eu- and hypoglycaemic clamp procedures have been used to suppress endogenous insulin secretion in healthy subjects. The use of exogenous insulin precluded the use of insulin as a parameter to be measured. We now suggest to use exogenous insulin lispro and an insulin-specific ELISA not cross reacting with insulin lispro. Thus, determination of insulin by ELISA in this experimental setting reflects endogenous insulin. A 39-year-old man with a surgically confirmed pancreatic insulinoma was studied under hyperinsulinaemic [lispro insulin 40 mU x m(-2) body surface x min(-1)] clamp conditions. Euglycaemia was achieved (3.8 /- 0.5 mmol/L) for 1 h and hypoglycaemia (2.36 /- 0.49 mmol/L) was achieved for another 30 min. Insulin was evaluated by ELISA (cross-reaction with lispro insulin < 0.006%, c-peptide < 0.01%, proinsulin < 0.001%) and by a nonselective RIA (cross-reaction with proinsulin 40%). In control subjects the euglycaemic hyperinsulinaemia suppressed c-peptide to 0.36 /- 0.03 ng/ml and hypoglycaemic hyperinsulinaemia to 0.29 /- 0.03 ng/ml. Endogenous insulin was suppressed to 2.8 /- 0.03 mU/L under euglycaemia and to 2.6 /- 0.03 mU/L under hypoglycaemia in control subjects. In the insulinoma patient apparently irregular but small changes in both c-peptide (1.43 /- 0.1 ng/ml) and more pronounced changes in endogenous insulin concentrations 4.41 /- 0.1 mU/l under euglycaemia and 5.35 /- 0.3 mU/l under hypoglycaemic conditions, were observed. The basal level of insulin (ELISA insulin 4.6 mU/L) and c-peptide (1.7 ng/ml) were not markedly elevated. Determination of insulin allowed better characterization of irregular pulses because of the shorter half-life of insulin relative to c-peptide. The new modification of sequential eu- and hypoglycaemic clamp procedures should also be useful in pharmacological studies of insulinotropic substances. Direct measurement of peripheral insulin may be more sensitive than c-peptide to detect low levels of autonomous insulin secretion in small insulinomas.- - - - - - - - - - ranking = 2keywords = hypoglycaemia (Clic here for more details about this article) |
7/64. Seizure recurrence in temporal lobe epilepsy.We report on a patient with clinical, electroencephalographic and radiological features of temporal lobe epilepsy, whose seizures were initially controlled with antiepileptic treatment. Five years after the onset of seizures, he developed more frequent and prolonged episodes of confusion, which were misinterpreted as secondary to temporal lobe epilepsy. Further investigation revealed the presence of hypoglycaemia and the eventual diagnosis of metastatic insulinoma.- - - - - - - - - - ranking = 1keywords = hypoglycaemia (Clic here for more details about this article) |
8/64. Uncontrolled insulin secretion from a childhood pancreatic beta-cell adenoma is not due to the functional loss of ATP-sensitive potassium channels.We report the case of an 8-year-old child who presented with severe hyperinsulinaemic hypoglycaemia due to a pancreatic islet cell adenoma. In vivo, there was no beneficial response to the hyperglycaemia-inducing agent diazoxide and as a consequence the child underwent a subtotal pancreatectomy. in vitro studies of adenomatous beta-cells revealed no operational defects in ATP-sensitive potassium channel activity and appropriate responses to diazoxide. In comparison with patients with focal adenomatous hyperplasia, genetic analysis of the isolated adenoma showed no loss of heterozygosity for chromosome 11p15 and expression of the cyclin-dependent kinase inhibitor p57(kip2). This case illustrates that the excess insulin secretion from an infantile adenoma has an aetiology different from that observed in hyperinsulinism in infancy.- - - - - - - - - - ranking = 1keywords = hypoglycaemia (Clic here for more details about this article) |
9/64. insulinoma presenting with hyperandrogenism: a case report and a literature review.An 18-year-old woman presented with a 6-month history of amenorrhoea and hyperandrogenism. Three months later she developed several episodes of fasting hypoglycaemia and was subsequently diagnosed with an insulinoma. Hyperinsulinaemia was observed in association with an elevated serum testosterone level. Surgical removal of the insulinoma resulted in resolution of the clinical and biochemical features of the polycystic ovarian syndrome (PCOS). Polycystic ovarian syndrome is unusual in a patient having an insulinoma. The rarity of this association may be the result of the late age of onset of this type of tumour, intermittent secretion of excessive insulin by the tumour, the degree of hyperinsulinism or other factors extrinsic to the insulin receptor that may facilitate insulin activity. However, we could not discover how our patient differs in having had PCOS from the majority of women with insulinoma who do not. If other patients with insulinoma are subsequently found to have hyperandrogenism, then this tumour might be added to the differential diagnosis of causes of anovulatory cycles and hyperandrogenaemia, although rare the association would be uncommon.- - - - - - - - - - ranking = 1keywords = hypoglycaemia (Clic here for more details about this article) |
10/64. Intractable pruritus associated with insulinoma in the absence of multiple endocrine neoplasia: a novel paraneoplastic phenomenon.insulinoma is a rare tumour, the main symptoms of which are related to hypoglycaemia. Generalized pruritus has been described in association with the multiple endocrine neoplasia syndrome (MEN II or Sipple's syndrome) as a paraneoplastic phenomenon. Further, pruritus is known to be part of the paraneoplastic syndrome in other solid tumours. This case describes a patient presenting with symptoms of Whipple's triad (hypoglycaemic symptoms during fasting, low fasting blood sugar levels and symptoms relieved by intravenous dextrose). Magnetic resonance scanning and selective mesenteric angiography demonstrated a probable pancreatic neuroendocrine tumour. Pituitary fossa imaging and endocrine profile excluded the MEN I syndrome. Symptoms resolved after surgical removal of the tumour. histology confirmed a pancreatic neuroendocrine tumour. The association between pruritus and insulinoma appears to be a novel paraneoplastic phenomenon.- - - - - - - - - - ranking = 1keywords = hypoglycaemia (Clic here for more details about this article) |
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