Recurrent hyperinsulinemic hypoglycemia caused by an insulin-secreting insulinoma

Molecular and Clinical Spectrum of Primary Hyperparathyroidism

Recent data suggest an increase in the overall incidence of parathyroid disorders, with primary hyperparathyroidism (PHPT) being the most prevalent parathyroid disorder. PHPT is associated with morbidities (fractures, kidney stones, chronic kidney disease) and increased risk of death. The symptoms of PHPT can be nonspecific, potentially delaying the diagnosis. Approximately 15% of patients with PHPT have an underlying heritable form of PHPT that may be associated with extraparathyroidal manifestations, requiring active surveillance for these manifestations as seen in multiple endocrine neoplasia type 1 and 2A. Genetic testing for heritable forms should be offered to patients with multiglandular disease, recurrent PHPT, young onset PHPT (age ≤40 years), and those with a family history of parathyroid tumors. However, the underlying genetic cause for the majority of patients with heritable forms of PHPT remains unknown. Distinction between sporadic and heritable forms of PHPT is useful in surgical planning for parathyroidectomy and has implications for the family. The genes currently known to be associated with heritable forms of PHPT account for approximately half of sporadic parathyroid tumors. But the genetic cause in approximately half of the sporadic parathyroid tumors remains unknown. Furthermore, there is no systemic therapy for parathyroid carcinoma, a rare but potentially fatal cause of PHPT. Improved understanding of the molecular characteristics of parathyroid tumors will allow us to identify biomarkers for diagnosis and novel targets for therapy.

LONG-TERM EFFECT OF 177LU-DOTATATE ON SEVERE AND REFRACTORY HYPOGLYCEMIA ASSOCIATED WITH MALIGNANT INSULINOMA

Objective

Malignant insulinoma is an extremely uncommon tumor that is usually accompanied by severe hypoglycemia that is difficult to manage. At this time, the long-term effect of ¹⁷⁷Lu-DOTATATE (lutetium [Lu-177]-DOTA-Tyr3-octreotate) on this tumor is not well known.

Methods

We report a case of severe, life-threatening, and refractory hypoglycemia associated with malignant insulinoma treated with ¹⁷⁷Lu-DOTATATE.

Results

A 51-year-old woman was referred because of severe, life-threatening, and refractory hypoglycemia due to malignant insulinoma. The patient had been treated unsuccessfully with chemotherapy, targeted therapies, and symptomatic therapy with diazoxide, steroids, and somatostatin analogues without success. ¹⁷⁷Lu-DOTATATE adequately controlled her hypoglycemia after the other conventional treatments failed.

Conclusion

¹⁷⁷Lu-DOTATATE was effective in providing rapid and long-term symptomatic control of the hypoglycemia and significantly improved the quality of life of the patient.

Cognitive, neurophysiologic and metabolic sequelae of previous hypoglycemic coma revealed by hyperinsulinemic-hypoglycemic clamp in type 1 diabetic patients

To examine the relationship between electroencephalographic (EEG) activity and hypoglycemia unawareness, we investigated early parameters of vigilance and awareness of various symptom categories in response to hypoglycemia in intensively treated type 1 diabetic (T1DM) patients with different degrees of hypoglycemia unawareness. Hypoglycemia was induced with a hyperinsulinemic-hypoglycemic clamp in six T1DM patients with a history of hypoglycemia unawareness previous severe hypoglycemic coma (SH) and in six T1DM patients without (C) history of hypoglycemia unawareness previous severe hypoglycemic coma. Cognitive function tests (four choice reaction time), counterregulatory responses (adrenaline), and symptomatic responses were evaluated at euglycemia (90 mg/dl) and during step-wise plasma glucose reduction (68, 58 and 49 mg/dl). EEG activity was recorded continuously throughout the study and analyzed by spectral analysis. Cognitive function deteriorated significantly at a glucose threshold of 55 ± 1 mg/dl in both groups (p = ns) during hypoglycemia, while the glucose threshold for autonomic symptoms was significantly lower in SH patients than in C patients (49 ± 1 vs. 54 ± 1 mg/dl, p < 0.05, respectively). In SH patients, eye-closed resting EEG showed a correlation between the mean dominance frequency and plasma glucose (r = 0.62, p < 0.001). Theta relative power increased during controlled hypoglycemia compared to euglycemia (21.6 ± 6 vs. 15.5 ± 3% Hz p < 0.05) and was higher than in the C group (21.6 ± 6 vs. 13.8 ± 3%, p < 0.03). The cognitive task beta activity was lower in the SH group than in the C group (14.8 ± 3 Hz, vs. 22.6 ± 4 vs. p < 0.03). Controlled hypoglycemia elicits cognitive dysfunction in both C and SH patients; however, significant EEG alterations during hypoglycemia were detected mainly in patients with a history of hypoglycemia unawareness and previous severe hypoglycemic coma. These data suggest that prior episodes of hypoglycemic coma modulate brain electric activity.

Recurrent insulinoma in a 10-year-old boy with Down's syndrome

An insulinoma is a rare tumour with an incidence of four cases per million per year in adults. The incidence in children is not established. There is limited literature available in children with insulinoma, and only one case is reported in association with Down’s syndrome in adults. Insulinoma diagnosis is frequently missed in adults as well as in children. The Whipple triad is the most striking feature although it has limited application in young children. Hypoglycaemia with elevated insulin, C-peptide and absent ketones is highly suggestive of hyperinsulinism. We present a case of 10-year-old boy with Down’s syndrome with recurrent insulinoma. He was initially misdiagnosed as having an adrenal insufficiency and developed cushingoid features and obesity secondary to hydrocortisone treatment and excessive sugar intake. The tumour was successfully localised in the head of the pancreas with an MRI and octreotide scan on first presentation. Medical treatment with diazoxide and octreotide could not achieve normal blood glucose levels. The insulinoma was laparoscopically enucleated and pathological examination confirmed a neuroendocrine tumour. Subsequently, he had complete resolution of symptoms. He had a recurrence after 2 years with frequent episodes of hypoglycaemia. The biochemical workup was suggestive of hyperinsulinism. MRI and PET scan confirmed the recurrence at the same site (head of the pancreas). He had an open laparotomy for insulinoma resection. The pathology was consistent with benign insulinoma, and subsequently, he had complete resolution of symptoms.

Endoscopic ultrasound-guided fine-needle aspiration biopsy (EUS-FNA) in insulinomas: Indications and clinical relevance in a single investigator cohort of 47 patients

PURPOSE

This study was aimed to investigate the role and relevance of endoscopic ultrasound-guided fine-needle aspiration biopsy in the diagnostic work-up of insulinomas.

METHODS

We have analysed the frequency, clinical indications, success rate (obtaining diagnostic tissue), diagnostic accuracy (in comparison to the pathological diagnosis after surgery), complications, and tolerability of endoscopic ultrasound-guided fine-needle aspiration biopsy and the localization and size of the lesions in 47 consecutive patients (29 females, 18 males; 46 ± 15 years) who had surgery for insulinoma following fasting test and were explored by single investigator EUS 1994-2015.

RESULTS

Endoscopic ultrasound-guided fine-needle aspiration biopsy was performed in 21 % (10/47) of the patients. The clinical indications for endoscopic ultrasound-guided fine-needle aspiration biopsy were non-conclusive result of fasting test (n = 7), missing toxicology (n = 2), suspected malignancy at EUS (n = 1), suspicious extra-pancreatic localization of the lesion (n = 1). The diagnostic success rate of the procedure was 80 % (8/10 cases), the diagnostic accuracy of the fine-needle aspiration biopsy 70 % (7/10 cases). The lesions undergoing endoscopic ultrasound-guided fine-needle aspiration biopsy were localized in the cauda (n = 5), corpus (n = 2), caput/processus uncinatus (n = 3), the diameter of the tumors was 21 ± 18 (10-70) mm. Only one accidental vascular puncture without any clinical complication occurred and all patients tolerated the procedure well.

CONCLUSIONS

In the majority of cases, positive fasting test, negative toxicology, and detection of a typical pancreatic lesion at endoscopic ultrasound is sufficient for the diagnosis of insulinoma and the definition of the appropriate surgical strategy. Based on our data, we suggest including endoscopic ultrasound-guided fine-needle aspiration biopsy in the diagnostic work-up of organic hyperinsulinism in selected patients with inconclusive or uncertain diagnosis before surgery.

Post-Gastric Bypass Hypoglycemia

Obesity is a major public health problem worldwide. Obesity-related illnesses, such as coronary heart disease, type 2 diabetes, hypertension, dyslipidemia, stroke, sleep apnea, and several forms of cancer (endometrial, breast, and colon), contribute to a significant number of deaths in the USA. Bariatric surgery, including the Roux-en-Y gastric bypass (RYGB) procedure, has demonstrated significant improvements in obesity and obesity-related co-morbidities and is becoming more popular as the number of obese individuals rises. Despite the reported benefits of bariatric surgery, there are potential complications that physicians need to be aware of as the number of patients undergoing these procedures continues to increase. One challenging and potentially life-threatening complication that to date is not well understood is post-RYGB surgery hypoglycemia (PGBH). In this review, we will present the definition, historical perspective, diagnostic approach, currently available treatment options, and anecdotal assessment and treatment algorithm for this disorder.

Management of endocrine disease: a clinical update on tumor-induced hypoglycemia

Tumor-induced hypoglycemia (TIH) is a rare clinical entity that may occur in patients with diverse kinds of tumor lineages and that may be caused by different mechanisms. These pathogenic mechanisms include the eutopic insulin secretion by a pancreatic islet β-cell tumor, and also the ectopic tumor insulin secretion by non-islet-cell tumor, such as bronchial carcinoids and gastrointestinal stromal tumors. Insulinoma is, by far, the most common tumor associated with clinical and biochemical hypoglycemia. Insulinomas are usually single, small, sporadic, and intrapancreatic benign tumors. Only 5-10% of insulinomas are malignant. Insulinoma may be associated with the multiple endocrine neoplasia type 1 in 4-6% of patients. Medical therapy with diazoxide or somatostatin analogs has been used to control hypoglycemic symptoms in patients with insulinoma, but only surgical excision by enucleation or partial pancreatectomy is curative. Other mechanisms that may, more uncommonly, account for tumor-associated hypoglycemia without excess insulin secretion are the tumor secretion of peptides capable of causing glucose consumption by different mechanisms. These are the cases of tumors producing IGF2 precursors, IGF1, somatostatin, and glucagon-like peptide 1. Tumor autoimmune hypoglycemia occurs due to the production of insulin by tumor cells or insulin receptor autoantibodies. Lastly, massive tumor burden with glucose consumption, massive tumor liver infiltration, and pituitary or adrenal glands destruction by tumor are other mechanisms for TIH in cases of large and aggressive neoplasias.

Hyperinsulinaemic hypoglycaemia:genetic mechanisms, diagnosis and management

Hyperinsulinaemic hypoglycaemia (HH) is characterized by unregulated insulin secretion from pancreatic β-cells. Untreated hypoglycaemia in infants can lead to seizures, developmental delay, and subsequent permanent brain injury. Early identification and meticulous managementof these patients is vital to prevent neurological insult. Mutations in eight different genes (ABCC8, KCNJ11, GLUD1, CGK, HADH, SLC16A1, HNF4A and UCP2) have been identified to date in patients with congenital forms of hyperinsulinism (CHI). The most severe forms of CHI are due to mutations in ABCC8 and KCJN11, which encode the two components of pancreatic β-cell ATP-sensitive potassium channel. Recent advancement in understanding the genetic aetiology, histological characterisation into focal and diffuse variety combined with improved imaging (such as fluorine 18 L-3, 4-dihydroxyphenylalanine positron emission tomography 18F-DOPA-PET scanning) and laparoscopic surgical techniques have greatly improved management. In adults, HH can be due to an insulinoma, pancreatogenous hypoglycaemic syndrome, post gastric-bypass surgery for morbid obesity as well as to mutations in insulin receptor gene. This review provides an overview of the molecular basis of CHI and outlines the clinical presentation, diagnostic criteria, and management of these patients.

Evaluation and management of adult hypoglycemic disorders: an Endocrine Society Clinical Practice Guideline

OBJECTIVE

The aim is to provide guidelines for the evaluation and management of adults with hypoglycemic disorders, including those with diabetes mellitus.

EVIDENCE

Using the recommendations of the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) system, the quality of evidence is graded very low (plus sign in circle ooo), low (plus sign in circle plus sign in circle oo), moderate (plus sign in circle plus sign in circle plus sign in circle o), or high (plus sign in circle plus sign in circle plus sign in circle plus sign in circle).

CONCLUSIONS

We recommend evaluation and management of hypoglycemia only in patients in whom Whipple's triad--symptoms, signs, or both consistent with hypoglycemia, a low plasma glucose concentration, and resolution of those symptoms or signs after the plasma glucose concentration is raised--is documented. In patients with hypoglycemia without diabetes mellitus, we recommend the following strategy. First, pursue clinical clues to potential hypoglycemic etiologies--drugs, critical illnesses, hormone deficiencies, nonislet cell tumors. In the absence of these causes, the differential diagnosis narrows to accidental, surreptitious, or even malicious hypoglycemia or endogenous hyperinsulinism. In patients suspected of having endogenous hyperinsulinism, measure plasma glucose, insulin, C-peptide, proinsulin, beta-hydroxybutyrate, and circulating oral hypoglycemic agents during an episode of hypoglycemia and measure insulin antibodies. Insulin or insulin secretagogue treatment of diabetes mellitus is the most common cause of hypoglycemia. We recommend the practice of hypoglycemia risk factor reduction--addressing the issue of hypoglycemia, applying the principles of intensive glycemic therapy, and considering both the conventional risk factors and those indicative of compromised defenses against falling plasma glucose concentrations--in persons with diabetes.