Oxyhyperglycemia is a special type of
impaired glucose tolerance
Prediabetes is a component of the metabolic syndrome and is characterized by elevated blood sugar levels that fall below the threshold to diagnose diabetes mellitus. It usually does not cause symptoms but people with prediabetes often have obesit ...
characterized by a rapid and transient
hyperglycemia
Hyperglycemia is a condition in which an excessive amount of glucose circulates in the blood plasma. This is generally a blood sugar level higher than 11.1 mmol/L (200 mg/dL), but symptoms may not start to become noticeable until even ...
(i.e. rise in blood glucose) spike after an oral intake of glucose, the peak of this spike being high enough to cause transient, symptom free
glycosuria
Glycosuria is the excretion of glucose into the urine. Ordinarily, urine contains no glucose because the kidneys are able to reabsorb all of the filtered glucose from the tubular fluid back into the bloodstream. Glycosuria is nearly always caused ...
(i.e. detectable glucose in urine), but this hyperglycemia reverses rapidly and may even go to hypoglycemia in the later phase. This sharp downstroke overshooting towards
hypoglycemia
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 belo ...
distinguishes this pathologic phenomenon from the artificial hyperglycemia inducible by an intravenous bolus dose of a large amount of glucose solution. Early
dumping syndrome
Dumping syndrome occurs when food, especially sugar, moves too quickly from the stomach to the duodenum—the first part of the small intestine—in the upper gastrointestinal (GI) tract. This condition is also called rapid gastric emptying. It ...
patients usually have oxyhyperglycemia associated with any meal or
OGTT
The glucose tolerance test (GTT, not to be confused with GGT test) is a medical test in which glucose is given and blood samples taken afterward to determine how quickly it is cleared from the blood. The test is usually used to test for diabetes, ...
.
The Greek root ''oxy'' means "sharp" or "pointy". The
OGTT
The glucose tolerance test (GTT, not to be confused with GGT test) is a medical test in which glucose is given and blood samples taken afterward to determine how quickly it is cleared from the blood. The test is usually used to test for diabetes, ...
curve in this condition appears sharp and somewhat pointy (at least relative to the other forms of hyperglycemia)- hence this name.Dorlands dictionary defines oxyhyperglycemia as:
:"A condition in which there is slight glycosuria and an
Oral Glucose Tolerance curve that rises about 180–200 mg/dL but returns to fasting value 2.5 hrs after ingestion of the glucose."
A blood level of approximately 180 mg/dL is the renal glucose threshold below which all glucose is reabsorbed from glomerular filtrate. But at blood concentrations above the
renal threshold
In physiology, the renal threshold is the concentration of a substance dissolved in the blood above which the kidneys begin to remove it into the urine. When the renal threshold of a substance is exceeded, reabsorption of the substance by the proxi ...
sugar starts appearing in the urine.Oxyhyperglycemia, like other forms of
Impaired glucose tolerance
Prediabetes is a component of the metabolic syndrome and is characterized by elevated blood sugar levels that fall below the threshold to diagnose diabetes mellitus. It usually does not cause symptoms but people with prediabetes often have obesit ...
has also been suggested to be a
prediabetic condition
Cause
Oxyhyperglycemia is most commonly caused by early
dumping syndrome
Dumping syndrome occurs when food, especially sugar, moves too quickly from the stomach to the duodenum—the first part of the small intestine—in the upper gastrointestinal (GI) tract. This condition is also called rapid gastric emptying. It ...
, but it can rarely caused by other conditions like
Graves' disease
Graves' disease (german: Morbus Basedow), also known as toxic diffuse goiter, is an autoimmune disease that affects the thyroid. It frequently results in and is the most common cause of hyperthyroidism. It also often results in an enlarged thyr ...
. It was first described by Lawrence et al. in 1936 as often happening after gastroenterostomy. It is seen in most forms of gastrectomy, gastric bypass and gastrostomy procedures, all of which are surgical causes of dumping syndrome.
Mechanism
In early
dumping syndrome
Dumping syndrome occurs when food, especially sugar, moves too quickly from the stomach to the duodenum—the first part of the small intestine—in the upper gastrointestinal (GI) tract. This condition is also called rapid gastric emptying. It ...
,
pancreatic
The pancreas is an Organ (anatomy), organ of the digestive system and endocrine system of vertebrates. In humans, it is located in the abdominal cavity, abdomen behind the stomach and functions as a gland. The pancreas is a mixed or heterocrine ...
glucagon
Glucagon is a peptide hormone, produced by alpha cells of the pancreas. It raises concentration of glucose and fatty acids in the bloodstream, and is considered to be the main catabolic hormone of the body. It is also used as a Glucagon (medicati ...
is augmented in the early
postprandial
Prandial relates to a meal. Postprandial (from post prandium) means after eating a meal, while preprandial is before a meal.
Usages of postprandial
The term ''postprandial'' is used in many contexts.
Gastronomic or social
Refers to activities p ...
period, probably through stimulation the
catecholamine
A catecholamine (; abbreviated CA) is a monoamine neurotransmitter, an organic compound that has a catechol (benzene with two hydroxyl side groups next to each other) and a side-chain amine.
Catechol can be either a free molecule or a subst ...
s involved in the generalized autonomic surge induced by the osmotic load, but at 120 min, when most of the
hypoglycemia
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 belo ...
s are encountered, pancreatic glucagon is no longer detectable, likely through inhibition by
GLP-1
Glucagon-like peptide-1 (GLP-1) is a 30- or 31-amino-acid-long peptide hormone deriving from the tissue-specific posttranslational processing of the proglucagon peptide. It is produced and secreted by intestinal enteroendocrine L-cells and certa ...
.
Incretin
Incretins are a group of metabolic hormones that stimulate a decrease in blood glucose levels. Incretins are released after eating and augment the secretion of insulin released from pancreatic beta cells of the islets of Langerhans by a blood-gl ...
s including
GLP1
Glucagon-like peptide-1 (GLP-1) is a 30- or 31-amino-acid-long peptide hormone deriving from the tissue-specific posttranslational processing of the proglucagon peptide. It is produced and secreted by intestinal enteroendocrine L-cells and certa ...
and
GIP also bring in the late dumping effects including the
insulin
Insulin (, from Latin ''insula'', 'island') is a peptide hormone produced by beta cells of the pancreatic islets encoded in humans by the ''INS'' gene. It is considered to be the main anabolic hormone of the body. It regulates the metabolism o ...
rise and the
reactive hypoglycemia
Reactive hypoglycemia, postprandial hypoglycemia, or sugar crash is a term describing recurrent episodes of symptomatic hypoglycemia occurring within four hours"Hypoglycemia." It can also be referred to as "sugar crash" or "glucose crash." Nati ...
.
Diagnosis
Distinction from regular impaired glucose tolerance
Most patients (or animals) with prediabetic type
impaired glucose tolerance
Prediabetes is a component of the metabolic syndrome and is characterized by elevated blood sugar levels that fall below the threshold to diagnose diabetes mellitus. It usually does not cause symptoms but people with prediabetes often have obesit ...
(serum glucose 140–200 mg/dL at 2 hours after
OGTT
The glucose tolerance test (GTT, not to be confused with GGT test) is a medical test in which glucose is given and blood samples taken afterward to determine how quickly it is cleared from the blood. The test is usually used to test for diabetes, ...
) are generally not oxyhyperglycemic because:
# Glycosuria is not necessary for mild impaired glucose tolerance (e.g. at approx 140–180 mg/dL range of blood glucose), is necessary for oxyhyperglycemia (i.e. peak >renal threshold).
# In contrast to the commonly seen shallow OGTT curve, amplitude of the pointy spike in oxyhyperglycemia need not necessarily be restricted to only prediabetic range and in severe oxyhyperglycemia it may cross 250 mg/dL. In oxyhyperglycemia, by two hours, the glucose not only comes back to pre-diabetic range it may even start shooting below the fasting baseline.
# In oxyhyperglycemia, both the upstroke (by 30 minutes) and down stroke (by 2.5 hr) happens quite fast which is unusual for other forms of prediabetes. In most cases of impaired tolerance, glucose levels usually do not come down as quickly, rather lasts for 2 hours or more. Whereas if the oxyhyperglycemia is due to an early dumping syndrome it may be followed by a late dumping syndrome which may even have a
hypoglycemic
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 belo ...
state. For animal studies, occasionally oxyhyperglycemia is written as synonymous for impaired glucose tolerance
[Journal of Endocrinology (1999) 160, 285–289 http://joe.endocrinology-journals.org/content/160/2/285.full.pdf] but mostly in the right context of gastrectomy, thus actually implying its narrower meaning than impaired glucose tolerance.
References
{{Disease of the pancreas and glucose metabolism, state=expanded
Disorders of endocrine pancreas
Abnormal clinical and laboratory findings for blood