Hypoglycemia, also called low blood sugar, is a fall in blood sugar to levels below normal, typically below 70 mg/dL (3.9 mmol/L). Whipple's triad is used to properly identify hypoglycemic episodes. It is defined as blood glucose below 70 mg/dL (3.9 mmol/L), symptoms associated with hypoglycemia, and resolution of symptoms when blood sugar returns to normal. Hypoglycemia may result in headache, tiredness, clumsiness, trouble talking, confusion, fast heart rate, sweating, shakiness, nervousness, hunger, loss of consciousness, seizures, or death. Symptoms typically come on quickly.
The pancreas is an organ of the digestive system and endocrine system of vertebrates. In humans, it is located in the abdomen behind the stomach and functions as a gland. The pancreas is a mixed or heterocrine gland, i.e., it has both an endocrine and a digestive exocrine function. 99% of the pancreas is exocrine and 1% is endocrine. As an endocrine gland, it functions mostly to regulate blood sugar levels, secreting the hormones insulin, glucagon, somatostatin and pancreatic polypeptide. As a part of the digestive system, it functions as an exocrine gland secreting pancreatic juice into the duodenum through the pancreatic duct. This juice contains bicarbonate, which neutralizes acid entering the duodenum from the stomach; and digestive enzymes, which break down carbohydrates, proteins and fats in food entering the duodenum from the stomach.
Beta cells (β-cells), are specialized endocrine cells located within the pancreatic islets of Langerhans responsible for the production and release of insulin and amylin. Constituting ~50–70% of cells in human islets, beta cells play a vital role in maintaining blood glucose levels.Problems with beta cells can lead to disorders such as diabetes.
The blood sugar level, blood sugar concentration, blood glucose level, or glycemia, is the measure of glucose concentrated in the blood. The body tightly regulates blood glucose levels as a part of metabolic homeostasis.
The connecting peptide, or C-peptide, is a short 31-amino-acid polypeptide that connects insulin's A-chain to its B-chain in the proinsulin molecule. In the context of diabetes or hypoglycemia, a measurement of C-peptide blood serum levels can be used to distinguish between different conditions with similar clinical features.
Glucokinase is an enzyme that facilitates phosphorylation of glucose to glucose-6-phosphate. Glucokinase occurs in cells in the liver and pancreas of humans and most other vertebrates. In each of these organs it plays an important role in the regulation of carbohydrate metabolism by acting as a glucose sensor, triggering shifts in metabolism or cell function in response to rising or falling levels of glucose, such as occur after a meal or when fasting. Mutations of the gene for this enzyme can cause unusual forms of diabetes or hypoglycemia.
Hyperinsulinemic hypoglycemia describes the condition and effects of low blood glucose caused by excessive insulin. Hypoglycemia due to excess insulin is the most common type of serious hypoglycemia. It can be due to endogenous or injected insulin.
Hyperinsulinism refers to an above normal level of insulin in the blood of a person or animal. Normal insulin secretion and blood levels are closely related to the level of glucose in the blood, so that a given level of insulin can be normal for one blood glucose level but low or high for another. Hyperinsulinism can be associated with several types of medical problems, which can be roughly divided into two broad and largely non-overlapping categories: those tending toward reduced sensitivity to insulin and high blood glucose levels (hyperglycemia), and those tending toward excessive insulin secretion and low glucose levels (hypoglycemia).
Whipple's triad is a collection of three signs that suggests that a patient's symptoms result from hypoglycaemia that may indicate insulinoma. The essential conditions are symptoms of hypoglycaemia, low blood plasma glucose concentration, and relief of symptoms when plasma glucose concentration is increased. It was first described by the pancreatic surgeon Allen Whipple, who aimed to establish criteria for exploratory pancreatic surgery to look for insulinoma.
Amylin, or islet amyloid polypeptide (IAPP), is a 37-residue peptide hormone. It is co-secreted with insulin from the pancreatic β-cells in the ratio of approximately 100:1 (insulin:amylin). Amylin plays a role in glycemic regulation by slowing gastric emptying and promoting satiety, thereby preventing post-prandial spikes in blood glucose levels.
Reactive hypoglycemia, postprandial hypoglycemia, or sugar crash is a term describing recurrent episodes of symptomatic hypoglycemia occurring within four hours after a high carbohydrate meal in people with and without diabetes. The term is not necessarily a diagnosis since it requires an evaluation to determine the cause of the hypoglycemia.
Multiple endocrine neoplasia type 1 (MEN-1) is one of a group of disorders, the multiple endocrine neoplasias, that affect the endocrine system through development of neoplastic lesions in pituitary, parathyroid gland and pancreas. Individuals suffering from this disorder are prone to developing multiple endocrine and nonendocrine tumors. It was first described by Paul Wermer in 1954.
Type 1 diabetes (T1D), formerly known as juvenile diabetes, is an autoimmune disease that originates when cells that make insulin are destroyed by the immune system. Insulin is a hormone required for the cells to use blood sugar for energy and it helps regulate glucose levels in the bloodstream. Before treatment this results in high blood sugar levels in the body. The common symptoms of this elevated blood sugar are frequent urination, increased thirst, increased hunger, weight loss, and other serious complications. Additional symptoms may include blurry vision, tiredness, and slow wound healing. Symptoms typically develop over a short period of time, often a matter of weeks if not months.
The term diabetes includes several different metabolic disorders that all, if left untreated, result in abnormally high concentrations of a sugar called glucose in the blood. Diabetes mellitus type 1 results when the pancreas no longer produces significant amounts of the hormone insulin, usually owing to the autoimmune destruction of the insulin-producing beta cells of the pancreas. Diabetes mellitus type 2, in contrast, is now thought to result from autoimmune attacks on the pancreas and/or insulin resistance. The pancreas of a person with type 2 diabetes may be producing normal or even abnormally large amounts of insulin. Other forms of diabetes mellitus, such as the various forms of maturity-onset diabetes of the young, may represent some combination of insufficient insulin production and insulin resistance. Some degree of insulin resistance may also be present in a person with type 1 diabetes.
A VIPoma or vipoma is a rare endocrine tumor that overproduces vasoactive intestinal peptide. The incidence is about 1 per 10,000,000 per year. VIPomas usually originate from the non-β islet cells of the pancreas. They are sometimes associated with multiple endocrine neoplasia type 1. Roughly 50–75% of VIPomas are malignant, but even when they are benign, they are problematic because they tend to cause a specific syndrome: the massive amounts of VIP cause a syndrome of profound and chronic watery diarrhea and resultant dehydration, hypokalemia, achlorhydria, acidosis, flushing and hypotension, hypercalcemia, and hyperglycemia. This syndrome is called Verner–Morrison syndrome (VMS), WDHA syndrome, or pancreatic cholera syndrome (PCS). The eponym reflects the physicians who first described the syndrome.
Neuroendocrine tumors (NETs) are neoplasms that arise from cells of the endocrine (hormonal) and nervous systems. They most commonly occur in the intestine, where they are often called carcinoid tumors, but they are also found in the pancreas, lung, and the rest of the body.
An insulin tolerance test (ITT) is a medical diagnostic procedure during which insulin is injected into a patient's vein, after which blood glucose is measured at regular intervals. This procedure is performed to assess pituitary function, adrenal function, insulin sensitivity, and sometimes for other purposes. An ITT is usually ordered and interpreted by an endocrinologist.
Pancreatic neuroendocrine tumours, often referred to as "islet cell tumours", or "pancreatic endocrine tumours" are neuroendocrine neoplasms that arise from cells of the endocrine (hormonal) and nervous system within the pancreas.
In medicine, a nesidioblastoma is an uncommon, insulin-secreting, pancreatic neuroendocrine tumor (PanNET). The term dates to at least 1938. In that report, these lesions were adjudicated as histologically benign adenoma growths, that were associated with severe, long-standing hypoglycemia due to hyperinsulinism. Surgical removal corrected the low glucose problems. There is no rigorous definitional separation from insulinoma, other than the original emphasis that was placed on the observed precise histological recapitulation of normal islet cell structure within the adenomas, which lacked microscopic features of aggressivity.
A metastatic insulinoma is a rare form of a malignant insulinoma involving metastatic growth. An insulinoma is a small tumor localized to the pancreas, originating from islet beta cells, which produce an excess of insulin. The increase in insulin ultimately leads to hypoglycemia. Insulinomas are commonly benign tumors, but can metastasize and become malignant. The metastatic growth can be characterized as a local invasion or distal metastasis. However, insulinomas are often difficult to detect due to their relatively small size, with a diameter oftentimes less than 2 cm. Therefore, clinical appearance and pathology are not sufficient in diagnosing a malignant insulinoma. Malignant insulinomas are not easily treated, as they require various treatments dependent on each person's case.
