Hyperinsulinemic hypoglycemia
Encyclopedia
Hyperinsulinemic hypoglycemia describes the condition and effects of low blood glucose
Glucose
Glucose is a simple sugar and an important carbohydrate in biology. Cells use it as the primary source of energy and a metabolic intermediate...

 caused by excessive insulin
Insulin
Insulin is a hormone central to regulating carbohydrate and fat metabolism in the body. Insulin causes cells in the liver, muscle, and fat tissue to take up glucose from the blood, storing it as glycogen in the liver and muscle....

. Hypoglycemia
Hypoglycemia
Hypoglycemia or hypoglycæmia is the medical term for a state produced by a lower than normal level of blood glucose. The term literally means "under-sweet blood"...

 due to excess insulin is the most common type of serious hypoglycemia. It can be due to endogenous or injected insulin.

Causes

Hypoglycemia due to endogenous insulin can be congenital or acquired, apparent in the newborn period, or many years later. The hypoglycemia can be severe and life-threatening or a minor, occasional nuisance. By far the most common type of severe but transient hyperinsulinemic hypoglycemia occurs accidentally in persons with type 1 diabetes who take insulin.
  • Hypoglycemia due to endogenous insulin
    • Congenital hyperinsulinism
      Congenital hyperinsulinism
      Congenital hyperinsulinism is a medical term referring to a variety of congenital disorders in which hypoglycemia is caused by excessive insulin secretion. Congenital forms of hyperinsulinemic hypoglycemia can be transient or persistent, mild or severe. These conditions are present at birth and...

      • Transient neonatal hyperinsulinism (mechanism not known)
      • Focal hyperinsulinism (KATP channel disorders)
        • Paternal SUR1 mutation
          Mutation
          In molecular biology and genetics, mutations are changes in a genomic sequence: the DNA sequence of a cell's genome or the DNA or RNA sequence of a virus. They can be defined as sudden and spontaneous changes in the cell. Mutations are caused by radiation, viruses, transposons and mutagenic...

           with clonal loss of heterozygosity of 11p15
        • Paternal Kir6.2 mutation with clonal loss of heterozygosity of 11p15
      • Diffuse hyperinsulinism
        • KATP channel disorders
          • SUR1 mutations
          • Kir6.2 mutations
        • Glucokinase
          Glucokinase
          Glucokinase is an enzyme that facilitates phosphorylation of glucose to glucose-6-phosphate. Glucokinase occurs in cells in the liver, pancreas, gut, and brain of humans and most other vertebrates...

           gain-of-function mutations
        • Hyperammonemic
          Hyperammonemia
          Hyperammonemia is a metabolic disturbance characterised by an excess of ammonia in the blood. It is a dangerous condition that may lead to encephalopathy and death. It may be primary or secondary....

           hyperinsulinism (glutamate dehydrogenase gain-of-function mutations)
        • Short chain acyl coenzyme A dehydrogenase deficiency
        • Carbohydrate-deficient glycoprotein syndrome (Jaeken's Disease)
        • Beckwith-Wiedemann syndrome
          Beckwith-Wiedemann syndrome
          Beckwith–Wiedemann syndrome is an overgrowth disorder usually present at birth characterized by an increased risk of childhood cancer and certain congenital features. Originally, Dr...

          (suspected due to hyperinsulinism but pathophysiology uncertain: 11p15 mutation or IGF2 excess)
    • Acquired forms of hyperinsulinism
    • Insulinoma
      Insulinoma
      An insulinoma is a tumour of the pancreas that is derived from beta cells and secretes insulin.Beta cells secrete insulin in response to increases in blood glucose. The resulting increase in insulin acts to lower blood glucose back to normal levels at which point further secretion of insulin is...

      s (insulin-secreting tumor
      Tumor
      A tumor or tumour is commonly used as a synonym for a neoplasm that appears enlarged in size. Tumor is not synonymous with cancer...

      s)
      • Islet cell adenoma or adenomatosis
      • Islet cell carcinoma
        Islet cell carcinoma
        Islet cell carcinoma or nesidioblastoma is an uncommon cancer of the endocrine pancreas.It accounts for approximately 1.3% of pancreatic cancer.The term "nesidioblastoma" dates to at least 1938.-Survival:...

    • Adult nesidioblastosis
      Nesidioblastosis
      Nesidioblastosis is beta cell hyperplasia, consisting of the proliferation of islet cells from pancreatic ducts. It is a cause of hypoglycemia and hyperinsulinemia in a number of infants and newborns. Recently, this condition has been recognized in adolescents and adults and occurs in 5% of...

    • Autoimmune insulin syndrome
    • Noninsulinoma pancreatogenous hypoglycemia
    • Reactive hypoglycemia
      Reactive hypoglycemia
      Reactive hypoglycemia, or postprandial hypoglycemia, is a medical term describing recurrent episodes of symptomatic hypoglycemia occurring within 4 hours after a high carbohydrate meal in people who do not have diabetes...

       (also see idiopathic postprandial syndrome
      Idiopathic postprandial syndrome
      Idiopathic postprandial syndrome is a medical term describing a collection of symptoms popularly attributed to hypoglycemia but without demonstrably low blood glucose levels.People with this condition suffer from recurrent episodes of altered mood and cognitive...

      )
    • Gastric dumping syndrome
      Gastric dumping syndrome
      Gastric dumping syndrome, or rapid gastric emptying is a condition where ingested foods bypass the stomach too rapidly and enter the small intestine largely undigested. It happens when the upper end of the small intestine, the duodenum, expands too quickly due to the presence of hyperosmolar food...


  • Drug induced hyperinsulinism
    • Sulfonylurea
      Sulfonylurea
      Sulfonylurea derivatives are a class of antidiabetic drugs that are used in the management of diabetes mellitus type 2. They act by increasing insulin release from the beta cells in the pancreas.-First generation:* Carbutamide...

    • Aspirin
      Aspirin
      Aspirin , also known as acetylsalicylic acid , is a salicylate drug, often used as an analgesic to relieve minor aches and pains, as an antipyretic to reduce fever, and as an anti-inflammatory medication. It was discovered by Arthur Eichengrun, a chemist with the German company Bayer...

    • Pentamidine
      Pentamidine
      Pentamidine is an antimicrobial medication given for prevention and treatment of Pneumocystis pneumonia caused by Pneumocystis jirovecii , a severe interstitial type of pneumonia often seen in patients with HIV infection...

    • Quinine
      Quinine
      Quinine is a natural white crystalline alkaloid having antipyretic , antimalarial, analgesic , anti-inflammatory properties and a bitter taste. It is a stereoisomer of quinidine which, unlike quinine, is an anti-arrhythmic...

    • Disopyramide
      Disopyramide
      Disopyramide is an antiarrhythmic medication. It is a Class Ia antiarrhythmic used in the treatment of ventricular tachycardias...

    • Bordetella pertussis
      Bordetella pertussis
      Bordetella pertussis is a Gram-negative, aerobic coccobacillus of the genus Bordetella, and the causative agent of pertussis or whooping cough. Unlike B. bronchiseptica, B. pertussis is non-motile. Its virulence factors include pertussis toxin, filamentous hæmagglutinin, pertactin, fimbria, and...

       vaccine
      Vaccine
      A vaccine is a biological preparation that improves immunity to a particular disease. A vaccine typically contains an agent that resembles a disease-causing microorganism, and is often made from weakened or killed forms of the microbe or its toxins...

       or infection

  • Hypoglycemia due to exogenous (injected) insulin
    • Insulin self-injected for treatment of diabetes (i.e., diabetic hypoglycemia
      Diabetic hypoglycemia
      Diabetic hypoglycemia is a low blood glucose level occurring in a person with diabetes mellitus. It is one of the most common types of hypoglycemia seen in emergency departments and hospitals...

      )
    • Insulin self-injected surreptitiously (e.g., Munchausen syndrome
      Munchausen syndrome
      Münchausen syndrome is a psychiatric factitious disorder wherein those affected feign disease, illness, or psychological trauma to draw attention or sympathy to themselves. It is also sometimes known as hospital addiction syndrome or hospital hopper syndrome...

      )
    • Various forms of diagnostic challenge or "tolerance tests"
      • Insulin tolerance test for pituitary or adrenergic
        Autonomic nervous system
        The autonomic nervous system is the part of the peripheral nervous system that acts as a control system functioning largely below the level of consciousness, and controls visceral functions. The ANS affects heart rate, digestion, respiration rate, salivation, perspiration, diameter of the pupils,...

         response assessment
      • Protein
        Protein
        Proteins are biochemical compounds consisting of one or more polypeptides typically folded into a globular or fibrous form, facilitating a biological function. A polypeptide is a single linear polymer chain of amino acids bonded together by peptide bonds between the carboxyl and amino groups of...

         challenge
      • Leucine
        Leucine
        Leucine is a branched-chain α-amino acid with the chemical formula HO2CCHCH2CH2. Leucine is classified as a hydrophobic amino acid due to its aliphatic isobutyl side chain. It is encoded by six codons and is a major component of the subunits in ferritin, astacin and other 'buffer' proteins...

         challenge
      • Tolbutamide
        Tolbutamide
        Tolbutamide is a first generation potassium channel blocker, sulfonylurea oral hypoglycemic drug sold under the brand name Orinase. This drug may be used in the management of type II diabetes if diet alone is not effective. Tolbutamide stimulates the secretion of insulin by the pancreas...

         challenge
    • Insulin potentiation therapy
      Insulin potentiation therapy
      Insulin potentiation therapy is an alternative cancer treatment using insulin and low-dose chemotherapy.The therapeutic approach is said to take advantage of the endogenous molecular biology of cancer cells, specifically the secretion of insulin and insulin-like growth factor, and the interaction...

    • Insulin-induced coma for depression
      Clinical depression
      Major depressive disorder is a mental disorder characterized by an all-encompassing low mood accompanied by low self-esteem, and by loss of interest or pleasure in normally enjoyable activities...

       treatment

Genetics

There are several genetic forms of hyperinsulinemic hypoglycemia:
Type OMIM Gene Locus
HHF1 ABCC8
ABCC8
ATP-binding cassette transporter sub-family C member 8 is a protein that in humans is encoded by the ABCC8 gene. ABCC8 orthologs have been identified in all mammals for which complete genome data are available.-External links:* *...

11p15.1
HHF2 KCNJ11 11p15.1
HHF3 GCK
Glucokinase
Glucokinase is an enzyme that facilitates phosphorylation of glucose to glucose-6-phosphate. Glucokinase occurs in cells in the liver, pancreas, gut, and brain of humans and most other vertebrates...

7p15-p13
HHF4 HADH 4q22-q26
HHF5 INSR 19p13.2
HHF6 GLUD1 10q23.3
HHF7 SLC16A1
SLC16A1
Monocarboxylate transporter 1 is a protein that in humans is encoded by the SLC16A1 gene.-Further reading:...

1p13.2-p12

Signs, symptoms, and potential effects

Manifestations of hyperinsulinemic hypoglycemia vary by age and severity of the hypoglycemia. In general, most signs and symptoms can be attributed to (1) the effects on the brain of insufficient glucose (neuroglycopenia
Neuroglycopenia
Neuroglycopenia is a medical term that refers to a shortage of glucose in the brain, usually due to hypoglycemia. Glycopenia affects the function of neurons, and alters brain function and behavior...

) or (2) to the adrenergic response of the autonomic nervous system
Autonomic nervous system
The autonomic nervous system is the part of the peripheral nervous system that acts as a control system functioning largely below the level of consciousness, and controls visceral functions. The ANS affects heart rate, digestion, respiration rate, salivation, perspiration, diameter of the pupils,...

 to hypoglycemia. A few miscellaneous symptoms are harder to attribute to either of these causes. In most cases, all effects are reversed when normal glucose levels are restored.

There are uncommon cases of more persistent harm, and rarely even death due to severe hypoglycemia of this type. One reason hypoglycemia due to excessive insulin can be more dangerous is that insulin lowers the available amounts of most alternate brain fuels, such as ketone
Ketone
In organic chemistry, a ketone is an organic compound with the structure RCR', where R and R' can be a variety of atoms and groups of atoms. It features a carbonyl group bonded to two other carbon atoms. Many ketones are known and many are of great importance in industry and in biology...

s. Brain damage of various types ranging from stroke
Stroke
A stroke, previously known medically as a cerebrovascular accident , is the rapidly developing loss of brain function due to disturbance in the blood supply to the brain. This can be due to ischemia caused by blockage , or a hemorrhage...

-like focal effects to impaired memory and thinking can occur. Children who have prolonged or recurrent hyperinsulinemic hypoglycemia in infancy can suffer harm to their brains and may be developmentally delayed.

Diagnostic evaluation

When the cause of hypoglycemia is not obvious, the most valuable diagnostic information is obtained from a blood sample (a "critical specimen") drawn during the hypoglycemia. Detectable amounts of insulin are abnormal and indicate that hyperinsulinism is likely to be the cause. Other aspects of the person's metabolic state, especially low levels of free fatty acids, beta-hydroxybutyrate
Beta-hydroxybutyrate
beta-Hydroxybutyric acid is a ketone body. It is a chiral compound having two enantiomers, D-3-hydroxybutyric acid and L-3-hydroxybutyric acid. Like the other ketone bodies , levels of beta-hydroxybutyrate are raised in ketosis...

 and ketone
Ketone
In organic chemistry, a ketone is an organic compound with the structure RCR', where R and R' can be a variety of atoms and groups of atoms. It features a carbonyl group bonded to two other carbon atoms. Many ketones are known and many are of great importance in industry and in biology...

s, and either high or low levels of C-peptide
C-peptide
C-peptide is a protein that is produced in the body along with insulin. First preproinsulin is secreted with an A-chain, C-peptide, a B-chain, and a signal sequence. The signal sequence is cut off, leaving proinsulin...

 and proinsulin
Proinsulin
Proinsulin is the prohormone precursor to insulin made in the beta cells of the islets of Langerhans, specialized regions of the pancreas. In humans, proinsulin is encoded by the INS gene.- Synthesis and post-translational modification :...

 can provide confirmation.

Clinical features and circumstances can provide other indirect evidence of hyperinsulinism. For instance, babies with neonatal hyperinsulinism are often large for gestational age
Large for gestational age
Large for gestational age is an indication of high prenatal growth rate, often defined as a weight that lies above the 90th percentile for that gestational age...

 and may have other features such as enlarged heart and liver. Knowing that someone takes insulin or oral hypoglycemic agents for diabetes obviously makes insulin excess the presumptive cause of any hypoglycemia.

Most sulfonylureas and aspirin can be detected on a blood or urine drug screen tests, but insulin cannot. Endogenous and exogenous insulin can be distinguished by the presence or absence of C-peptide
C-peptide
C-peptide is a protein that is produced in the body along with insulin. First preproinsulin is secreted with an A-chain, C-peptide, a B-chain, and a signal sequence. The signal sequence is cut off, leaving proinsulin...

, a by-product of endogenous insulin secretion which is not present in pharmaceutical insulin. Some of the newer analog
Insulin analog
An insulin analog is an altered form of insulin, different from any occurring in nature, but still available to the human body for performing the same action as human insulin in terms of glycemic control...

 insulins are not measured by the usual insulin level assays.

Treatment

Acute hypoglycemia is reversed by raising the blood glucose. This is usually accomplished by eating or drinking 10-30 grams of carbohydrate
Carbohydrate
A carbohydrate is an organic compound with the empirical formula ; that is, consists only of carbon, hydrogen, and oxygen, with a hydrogen:oxygen atom ratio of 2:1 . However, there are exceptions to this. One common example would be deoxyribose, a component of DNA, which has the empirical...

. Carbohydrate is digested and raises blood sugar most rapidly if it is not eaten with protein
Protein
Proteins are biochemical compounds consisting of one or more polypeptides typically folded into a globular or fibrous form, facilitating a biological function. A polypeptide is a single linear polymer chain of amino acids bonded together by peptide bonds between the carboxyl and amino groups of...

 or fat
Fat
Fats consist of a wide group of compounds that are generally soluble in organic solvents and generally insoluble in water. Chemically, fats are triglycerides, triesters of glycerol and any of several fatty acids. Fats may be either solid or liquid at room temperature, depending on their structure...

. When hypoglycemia is more severe or carbohydrate cannot be given by mouth, glucagon
Glucagon
Glucagon, a hormone secreted by the pancreas, raises blood glucose levels. Its effect is opposite that of insulin, which lowers blood glucose levels. The pancreas releases glucagon when blood sugar levels fall too low. Glucagon causes the liver to convert stored glycogen into glucose, which is...

 can be injected intramuscularly or intravenously, or dextrose can be infused intravenously to raise the blood glucose. Most people recover fully even from severe hypoglycemia after the blood glucose is restored to normal. Recovery time varies from minutes to hours depending on the severity and duration of the hypoglycemia. Death or permanent brain damage resembling stroke
Stroke
A stroke, previously known medically as a cerebrovascular accident , is the rapidly developing loss of brain function due to disturbance in the blood supply to the brain. This can be due to ischemia caused by blockage , or a hemorrhage...

 can occur rarely as a result of severe hypoglycemia. See hypoglycemia
Hypoglycemia
Hypoglycemia or hypoglycæmia is the medical term for a state produced by a lower than normal level of blood glucose. The term literally means "under-sweet blood"...

 for more on effects, recovery, and risks.

Further therapy and prevention depends upon the specific cause.

Most hypoglycemia due to excessive insulin occurs in people who take insulin for type 1 diabetes
Diabetes mellitus
Diabetes mellitus, often simply referred to as diabetes, is a group of metabolic diseases in which a person has high blood sugar, either because the body does not produce enough insulin, or because cells do not respond to the insulin that is produced...

. Management of this hypoglycemia
Diabetic hypoglycemia
Diabetic hypoglycemia is a low blood glucose level occurring in a person with diabetes mellitus. It is one of the most common types of hypoglycemia seen in emergency departments and hospitals...

 is sugar or starch by mouth (or in severe cases, an injection of glucagon
Glucagon
Glucagon, a hormone secreted by the pancreas, raises blood glucose levels. Its effect is opposite that of insulin, which lowers blood glucose levels. The pancreas releases glucagon when blood sugar levels fall too low. Glucagon causes the liver to convert stored glycogen into glucose, which is...

 or intravenous dextrose). When the glucose has been restored, recovery is usually complete. Prevention of further episodes consists of maintaining balance between insulin, food, and exercise. Management of hypoglycemia due to treatment of type 2 diabetes
Diabetes mellitus type 2
Diabetes mellitus type 2formerly non-insulin-dependent diabetes mellitus or adult-onset diabetesis a metabolic disorder that is characterized by high blood glucose in the context of insulin resistance and relative insulin deficiency. Diabetes is often initially managed by increasing exercise and...

 is similar, and the dose of the oral hypoglycemic agent may need to be reduced. Reversal and prevention of hypoglycemia is a major aspect of the management of type 1 diabetes.

Hypoglycemia due to drug overdose or effect is supported with extra glucose until the drugs have been metabolized. The drug doses or combination often needs to be altered.

Hypoglycemia due to a tumor
Tumor
A tumor or tumour is commonly used as a synonym for a neoplasm that appears enlarged in size. Tumor is not synonymous with cancer...

 of the pancreas or elsewhere is usually curable by surgical removal. Most of these tumors are benign. Streptozotocin
Streptozotocin
Streptozotocin is a naturally occurring chemical that is particularly toxic to the insulin-producing beta cells of the pancreas in mammals...

 is a specific beta cell
Beta cell
Beta cells are a type of cell in the pancreas located in the so-called islets of Langerhans. They make up 65-80% of the cells in the islets.-Function:...

 toxin and has been used to treat insulin-producing pancreatic carcinoma
Carcinoma
Carcinoma is the medical term for the most common type of cancer occurring in humans. Put simply, a carcinoma is a cancer that begins in a tissue that lines the inner or outer surfaces of the body, and that generally arises from cells originating in the endodermal or ectodermal germ layer during...

.

Hyperinsulinism due to diffuse overactivity of beta cells, such as in many of the forms of congenital hyperinsulinism
Congenital hyperinsulinism
Congenital hyperinsulinism is a medical term referring to a variety of congenital disorders in which hypoglycemia is caused by excessive insulin secretion. Congenital forms of hyperinsulinemic hypoglycemia can be transient or persistent, mild or severe. These conditions are present at birth and...

, and more rarely in adults, can often be treated with diazoxide
Diazoxide
Diazoxide is a potassium channel activator, which causes local relaxation in smooth muscle by increasing membrane permeability to potassium ions...

 or a somatostatin
Somatostatin
Somatostatin is a peptide hormone that regulates the endocrine system and affects neurotransmission and cell proliferation via interaction with G-protein-coupled somatostatin receptors and inhibition of the release of numerous secondary hormones.Somatostatin...

 analog called octreotide
Octreotide
Octreotide is an octapeptide that mimics natural somatostatin pharmacologically, though it is a more potent inhibitor of growth hormone, glucagon, and insulin than the natural hormone...

. Diazoxide is given by mouth, octreotide by injection or continuous subcutaneous pump infusion. When congenital hyperinsulinism is due to focal defects of the insulin-secretion mechanism, surgical removal of that part of the pancreas may cure the problem. In more severe cases of persistent congenital hyperinsulinism unresponsive to drugs, a near-total pancreatectomy
Pancreatectomy
In medicine, a pancreatectomy is the surgical removal of all or part of the pancreas. Several types of pancreatectomy exist, including pancreaticoduodenectomy , distal pancreatectomy, segmental pancreatectomy, and total pancreatectomy...

 may be needed to prevent continuing hypoglycemia. Even after pancreatectomy, continuous glucose may be needed in the form of gastric infusion of formula
Infant formula
Infant formula is a manufactured food designed and marketed for feeding to babies and infants under 12 months of age, usually prepared for bottle-feeding or cup-feeding from powder or liquid . The U.S...

 or dextrose.

High dose glucocorticoid
Glucocorticoid
Glucocorticoids are a class of steroid hormones that bind to the glucocorticoid receptor , which is present in almost every vertebrate animal cell...

 is an older treatment used for presumptive transient hyperinsulinism but incurs side effects with prolonged use.

See also

  • hypoglycemia
    Hypoglycemia
    Hypoglycemia or hypoglycæmia is the medical term for a state produced by a lower than normal level of blood glucose. The term literally means "under-sweet blood"...

  • congenital hyperinsulinism
    Congenital hyperinsulinism
    Congenital hyperinsulinism is a medical term referring to a variety of congenital disorders in which hypoglycemia is caused by excessive insulin secretion. Congenital forms of hyperinsulinemic hypoglycemia can be transient or persistent, mild or severe. These conditions are present at birth and...

  • idiopathic hypoglycemia
    Idiopathic hypoglycemia
    Idiopathic hypoglycemia is, literally, a medical condition in which the glucose level in the blood is abnormally low due to an undeterminable cause. This is considered an incomplete and unsatisfactory diagnosis by physicians and is rarely used by endocrinologists, as it implies an unfinished...

  • diabetic hypoglycemia
    Diabetic hypoglycemia
    Diabetic hypoglycemia is a low blood glucose level occurring in a person with diabetes mellitus. It is one of the most common types of hypoglycemia seen in emergency departments and hospitals...

  • oral hypoglycemic agent
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