Insulinoma Health Dictionary

A collection of disorders in which some part of the body’s internal chemistry (see METABOLISM; CATABOLISM) is disrupted. Some of these disorders arise from inherited de?ciencies in which a speci?c ENZYME is absent or abnormal, or does not function properly. Other metabolic disorders occur because of malfunctions in the endocrine system (see ENDOCRINE GLANDS). There may be over- or underproduction of a hormone involved in the control of metabolic activities: a prime example is DIABETES MELLITUS – a disorder of sugar metabolism; others include CUSHING’S SYNDROME; hypothyroidism and hyperthyroidism (see THYROID GLAND, DISEASES OF); and insulinoma (an insulin-producing tumour of the pancreas). The bones can be affected by metabolic disorders such as osteoporosis, osteomalacia (rickets) and Paget’s disease (see under BONE, DISORDERS OF). PORPHYRIAS, HYPERLIPIDAEMIA, HYPERCALCAEMIA and gout are other examples of disordered metabolism.

There are also more than 200 identi?ed disorders described as inborn errors of metabolism. Some cause few problems; others are serious threats to an individual’s life. Individual disorders are, fortunately, rare – probably one child in 10,000 or 100,000; overall these inborn errors affect around one child in 1,000. Examples include GALACTOSAEMIA, PHENYLKETONURIA, porphyrias, TAY SACHS DISEASE and varieties of mucopolysaccharidosis, HOMOCYSTINURIA and hereditary fructose (a type of sugar) intolerance.... metabolic disorders

A hormone produced by the pancreas that regulates glucose levels in the blood. It is normally produced in response to raised glucose levels following a meal and promotes glucose absorption into the liver and muscle cells (where it is converted into energy). Insulin thus prevents a build-up of glucose and ensures that tissues have sufficient amounts of glucose. Failure of insulin production results in diabetes mellitus. An insulinoma is a rare tumour that causes excessive production of insulin and consequent attacks of hypoglycaemia.

Insulin replacement, self-administered by injection or through an infusion pump (see pump, insulin), is used in the treatment of diabetes mellitus. Insulin cannot be taken orally because it is destroyed by stomach acid. Preparations are produced from pig or ox pancreas or, more commonly, by genetic engineering. This treatment prevents excessively high glucose levels in blood (hyperglycaemia) and ketosis (a buildup of certain acids in the blood), which, in severe cases, may cause coma.

Too high a dose of insulin will cause hypoglycaemia, which can be relieved by consuming food or a sugary drink.

Severe hypoglycaemia may cause coma, for which emergency treatment with an injection of glucose or glucagon (a hormone that opposes the effects of insulin) is necessary.... insulin

Removal of all or part of the pancreas.

Pancreatectomy may be performed to treat pancreatitis or localized cancer of the pancreas (see pancreas, cancer of).

Rarely, it is performed to treat insulinomas.

Pancreatectomy may lead to diabetes mellitus and malabsorption.... pancreatectomy

n. a peptide (so-called because of its C shape) formed when insulin is produced from its precursor molecule, proinsulin. It is secreted in equal molar amounts to insulin. However, as it remains detectable in the plasma much longer than insulin it can be more easily assayed as a marker of the degree of insulin secretion. This can be useful to assess the ability of the pancreas to secrete insulin, for example when trying to determine whether somebody has type 1 or type 2 diabetes or to distinguish an insulin-secreting tumour (an *insulinoma) from surreptitious insulin usage in somebody presenting with unexplained hypoglycaemia.... c-peptide

n. a drug given to treat conditions in which the levels of blood sugar are chronically low (including *insulinoma).... diazoxide

any tumour arising in a cell of the pancreatic *islets of Langerhans. These tumours, which include *insulinomas, *glucagonomas, and *somatostatinomas, form one of the two major subclasses of gastrointestinal neuroendocrine tumours, the other being the *carcinoid tumours.... islet cell tumour

a combination of three clinical features that indicate the presence of an *insulinoma: (1) attacks of fainting, dizziness, and sweating on fasting; (2) severe hypoglycaemia present during the attacks; (3) relief from the attacks achieved by administering glucose. [A. O. Whipple]... whipple’s triad