hyperglycemia

An increase in the concentration of sugar in the blood. It is a feature of diabetes mellitus.

Definition

Hyperglycemia is a complex metabolic condition characterized by abnormally high levels of blood sugar (blood glucose) in circulating blood, usually as a result of diabetes mellitus (types 1 and 2), although it can sometimes occur in cystic fibrosis and near-drowning (submersion injury).

Description

Hyperglycemia, also known as diabetic ketoacidosis, is a condition that develops over a period of a few days as the blood glucose levels of a type 1 or type 2 diabetic gradually rise. Ketoacidosis occurs when increasing glucose levels are met by a lack of sufficient or effective insulin production, starting a sequence of physiologic events as follows:

• The combination of excess glucose production and low glucose utilization in the body raises levels of blood glucose, which leads to increased urinary output (diuresis) followed quickly by a loss of fluid and essential mineral salts (electrolytes) and, ultimately, dehydration. The loss of fluid may finally result in dehydration. If the entire process is severe enough over several hours (serum glucose levels over 800mg/dL), swelling can occur in the brain (cerebral edema), and coma can eventually result.
• In a metabolic shift to a catabolic (breaking down) process, cells throughout the body empty their electrolytes (sodium, potassium, and phosphate) into the bloodstream. Electrolytes control the fluid balance of the body and are important in muscle contraction, energy generation, and almost all major biochemical reactions in the body. As a result of electrolyte imbalance, many functions can become impaired.
• Free fatty acids from lipid stores are increased, encouraging the production of ketoacids in the liver, leading to an over-acidic condition (metabolic acidosis) that causes even more disruption in body processes.

Without effective treatment of the hyperglycemic episode, the child can lapse into a diabetic coma, which sometimes leads to death.

In diabetes type 2, which is characterized by insulin resistance, enhanced glucose production in the liver and decreased insulin secretion can be aggravated by low physical activity and/or a high-calorie, high-fat diet. Over time as glucose production accelerates, the child develops hyperglycemia or glucotoxicity and lipotoxicity (hyperlipidemia or high fat levels in the blood) as well. It is primarily thought to be a disease affecting sedentary, obese adults over age 40, but it is found in young people as well, most of them obese at the time of diagnosis. Pediatric type 2 diabetes is increasing in the early 2000s among adolescents and has become the fastest growing form of diabetes. Therefore, hyperglycemic episodes are also noted to be increasing in frequency among young people admitted to hospitals for treatment of diabetes.

Demographics

The incidence of hyperglycemia approximately parallels the incidence of diabetes type 1 cases, which represents about 70 percent of all diabetes cases (17 million Americans diagnosed) in the United States. It occurs more in whites than blacks or Asians. About 30 percent of all new cases of diabetes are children with diabetes type 2. Diabetes type 2 occurs more often in African American youth but also in Native Americans, white Americans, and Hispanic youth between ages 10 and 19. Those with type 2 have fewer symptoms and are not treated as frequently for hyperglycemia.

Causes and Symptoms

Diabetes is a chronic metabolic disorder with hyperglycemia, gradually rising levels of glucose, as its primary characteristic. As diabetes develops and symptoms increase, hyperglycemia becomes progressive but will occur only occasionally in the carefully managed diabetic patient. Hyperglycemia can be triggered by irregular self-administration of insulin, by insulin resistance or defective insulin response in the body, by stress or infection, and by the activation of certain autoimmune processes characteristic of type 1 diabetes. It occurs in 20 to 40 percent of children newly diagnosed with diabetes and in children who are not yet successfully managed. Many young type 2 diabetics do not have symptoms because their hyperglycemia is moderate compared to type 1 diabetics, and they are not taking insulin.

The first signs of hyperglycemia or ketoacidosis are frequent urination and increased thirst. The child may then show any of the following symptoms:

• flushed face
• dry skin
• dry mouth
• headache
• abdominal pain
• nausea and vomiting
• drowsiness and lethargy
• blurred vision
• fruity-smelling breath
• rapid heartbeat
• deep and labored breathing

When to Call the Doctor

The pediatrician or family doctor should be consulted about any sudden change in the child's urinary output, frequency of urination, or increased thirst, especially if accompanied by dry skin or mouth, flushed face, headache, abdominal pain, nausea or vomiting, unusual drowsiness and lack of movement, rapid heartbeat, or difficulty breathing. Parents should be aware of the last insulin injection if the child is on insulin therapy.

Diagnosis

Hyperglycemia can be diagnosed fairly quickly in known diabetic children. The non-fasting serum glucose will exceed 200mg/dL with classic symptoms such as increased urination, extreme thirst, dry skin or mouth, flushed face, headache, abdominal pain, nausea or vomiting, unusual drowsiness and lack of movement, rapid heartbeat, or difficulty breathing. If elevated glucose levels are present, the doctor will want to determine if ketoacidosis is also present by measuring levels of ketones in the blood serum and urine. Electrolyte levels will be measured along with carbon dioxide and pH and serum osmolality, which may indicate hypertonic dehydration. Routine screening of blood glucose levels and glucose tolerance tests is not recommended in children; symptoms are believed to help confirm hyperglycemia more readily. It is also not considered necessary to test non-obese children for autoimmune antibodies, which are more apt to be found in adult type 2 diabetics.

Treatment

Treatment for hyperglycemia must be delivered carefully and with close monitoring to avoid the risk of hypokalemia (higher than normal serum levels of potassium) and subsequent cerebral edema. Treatment will take place over a period of several days, including administration of insulin, usually in combination with administration of intravenous fluids and salts to restore fluid and electrolyte balance. Fluid intake and output is carefully monitored, and serum electrolytes are tested hourly or even more frequently to make sure balance is restored to support normal metabolic activity in the body. Children must be rehydrated very gradually; this can be done orally in mild hyperglycemia and over an extended period (30 to 36 hours) of intravenous administration with severe hyperglycemia. Administration of insulin helps move glucose back into cells, reduces glucose production by the liver, and stops the release of fatty acids. Insulin injections, while helping to normalize glucose production, also increase the risk of hypokalemia and abnormally low levels of glucose in the blood (hypoglycemia), the opposite of the hyperglycemic condition being corrected. Glucose is sometimes infused with the insulin to help avoid hypoglycemia. The insulin infusion will be slowed once hyperglycemia has been corrected (blood glucose levels less than 250mg/dL); in children with moderate hyperglycemia, this can often be accomplished within 24 hours. It may take several days, however, to restore normal cellular levels of potassium, sodium, and phosphate. The acidosis will be reversed, reflected in a gradual increase in pH.

In severe cases of hyperglycemia in which cerebral edema occurs, mannitol is administered at the first sign of edema, such as unconsciousness, difficulty breathing, severe headache, irregular heartbeat, or seizures. Changes can occur very rapidly. Children with moderate to severe hyperglycemia may be treated in an intensive care unit for continuous monitoring and rapid response capabilities.

In rare instances, a child may have a hyperglycemic episode that is triggered by a stressful situation or a physically challenging situation such as another illness. Transient hyperglycemia can be triggered by any type of stress that overtaxes the child's mental and physical resources. Stress hyperglycemia may be reversed completely when the stressors are removed or relieved. Temporary hyperglycemia of this type will still require careful monitoring for symptoms and testing and treatment as above if any symptoms occur.

Alternative Treatment

Although alternative treatment for diabetes includes taking chromium picolinate to improve the efficiency of insulin in glucose metabolism and coenzyme Q10 to improve blood circulation and stabilize blood glucose levels, hyperglycemia and diabetic ketoacidosis require immediate measures such as insulin injections and rehydration and cannot be treated by nutritional means.

Nutritional Concerns

Nutritional therapy along with insulin therapy can both help avoid hyperglycemia and relieve associated symptoms. Immediate medical attention is needed, however, and parents should not undertake correction of hyperglycemia or dehydration on their own. Basic nutritional requirements for children with diabetes can be provided by the pediatrician, based on the child's age, sex, weight, activity levels, food preferences, and ethnic or cultural factors. The recommended diet for those with diabetes calls for complex carbohydrates such as whole (unrefined) whole grains, plenty of fresh vegetables and fruits, with an overall intake of foods that are low in fat and high in fiber. This diet reduces the need for insulin and lowers fat levels in the blood, all helping to stabilize glucose levels.

Prognosis

The prognosis for children with mild to moderate hyperglycemia is good; the condition can usually be corrected within 24 hours. Severe hyperglycemia (serum glucose levels in the range of 800mg/dL) may lead to cerebral edema, coma, and death if not treated immediately. Hyperglycemia in children during severe illness is a risk factor for poor outcomes in the underlying illness and has been reported as a cause of increased mortality in pediatric intensive care units. Morbidity (the incidence of other diseases) and mortality are higher in adults than in children because of long-term complications that include vascular conditions, circulatory problems, nervous system disorders, liver problems, and heart disease.

Prevention

Occurrences of hyperglycemia can be prevented by careful monitoring of blood glucose levels and insulin injections while balancing exercise and diet. Diabetic adolescents are especially susceptible to hyperglycemia, since hormone levels are in flux and many adolescents exhibit erratic eating and sleeping patterns. Athletic activities can be beneficial, since exercise makes use of surplus blood glucose. Obese children must be encouraged to eat properly and to avoid the fats and sugary sweets that can lead to increased weight, decreased mobility, and hyperglycemia.

Nutritional Concerns

Nutrition, of course, is important in the treatment of diabetes and accordingly can play a role in preventing hyperglycemic episodes. Diabetic children must avoid sweetened and high-carbohydrate foods such as white flour and white sugar products and generally eat a high-fiber, low-fat diet consisting of whole grains, high quality protein (lean meat, eggs, low-fat dairy), fresh vegetables, and fresh fruits.

Parental Concerns

Parents of a diabetic child may live with the uncertainty of possible hyperglycemic episodes but can be reassured by knowing that continuous glucose monitoring, a proper diet as advised by the pediatrician, insulin therapy if prescribed, and appropriate exercise can control the disease and help avoid extremes that lead to hyperglycemia. It is important to maintain close contact with the child's diabetes team of professionals and to learn as much as possible about the disease and the symptoms to watch for in the child that may signal hyperglycemia. The parents of school-age children should make sure that teachers also understand the warning signs of hyperglycemia so that immediate medical attention can be given when needed.

See also Diabetes mellitus.

Resources

Books

American Diabetes Association Complete Guide to Diabetes: The Ultimate Home Reference from the Diabetes Experts, 3rd ed. New York: McGraw-Hill, 2002.

Becker, Gretchen. The First Year Type 2 Diabetes. New York: Marlowe, 2001.

Children's Hospital of Philadelphia Guide to Diabetes. New York: John Wiley & Sons, 2004.

Organizations

National Diabetes Education Program. One Diabetes Way, Bethesda, MD 20814–9692. Web site: www.ndep.nih.gov.

National Institute of Diabetes & Digestive & Kidney Diseases (NIDDK). NIH Building 31, Room 9A, 4 Center Drive, MSC 2560, Bethesda, MD 20892–2560. Web site: www.niddk.nih.gov.

Web Sites

National Diabetes Information Clearing House (NDIC). Available online at www.niddk.nih.gov (accessed October 18, 2004).

[Article by: L. Lee Culvert]

Characterized by or causing hyperglycemia.

• h. hyperosmolar nonketotic coma (HHNK) — a metabolic derangement in which there is an abnormally high serum glucose level without ketoacidosis. It can occur as a complication of borderline and unrecognized diabetes mellitus, in pancreatic disorders that interfere with the production of insulin, and in conditions marked by an excess of steroids, as in steroid therapy or acute stress conditions.
— Hyperosmolality, resulting from the extremely high concentration of sugar in the blood, causes a shift of water from the intracellular fluid (the less concentrated solution) into the blood (the higher concentrated solution). This results in cellular dehydration. Another symptom of HHNK, polyuria, occurs because the high plasma osmolality prevents the normal osmotic return of water to the blood by the renal tubules, and it is excreted in the urine. This leads to a decreased blood volume, which severely hampers the kidney's excretion of glucose and a vicious cycle is begun.

Please help improve this article by expanding it. Further information might be found on the talk page. (January 2007)

Hyperglycemia
Classification and external resources
ICD-10	R73.9
ICD-9	790.6

Hyperglycemia, hyperglycaemia, or high blood sugar is a condition in which an excessive amount of glucose circulates in the blood plasma. This is generally a blood glucose level of 10+ mmol/L (180 mg/dl), but symptoms may not start to become noticeable until later numbers such as 15-20+ mmol/L (270-360 mg/dl)or 15.2-32.6 mmol/L. However, chronic levels exceeding 125 mg/dl can produce organ damage.

The origin of the term is Greek: hyper-, meaning excessive; -glyc-, meaning sweet; and -emia, meaning "of the blood".

Contents 1 Causes 1.1 Diabetes mellitus 1.2 Drugs 1.3 Critical illness 1.4 Physiological stress 2 Measurement and definition 3 Effects 4 Symptoms 5 Treatment 6 See also 7 References 8 External links

Causes

Diabetes mellitus

Chronic hyperglycemia that persists even in fasting states is most commonly caused by diabetes mellitus, and in fact chronic hyperglycemia is the defining characteristic of the disease. Intermittent hyperglycemia may be present in prediabetic states. Acute episodes of hyperglycemia without an obvious cause may indicate developing diabetes or a predisposition to the disorder.

In diabetes mellitus, hyperglycemia is usually caused by low insulin levels and/or by resistance to insulin at the cellular level, depending on the type and state of the disease. Low insulin levels and/or insulin resistance prevent the body from converting glucose into glycogen (a starch-like source of energy stored mostly in the liver), which in turn makes it difficult or impossible to remove excess glucose from the blood. With normal glucose levels, the total amount of glucose in the blood at any given moment is only enough to provide energy to the body for 20-30 minutes, and so glucose levels must be precisely maintained by the body's internal control mechanisms. When the mechanisms fail in a way that allows glucose to rise to abnormal levels, hyperglycemia is the result.

Drugs

Certain medications increase the risk of hyperglycemia, including beta blockers, epinephrine, thiazide diuretics, corticosteroids, niacin, pentamidine, protease inhibitors, L-asparaginase,^[1] and some antipsychotic agents.^[2] The acute administration of stimulants such as amphetamine typically produces hyperglycemia; chronic use, however, produces hypoglycemia.

Critical illness

A high proportion of patients suffering an acute stress such as stroke or myocardial infarction may develop hyperglycemia, even in the absence of a diagnosis of diabetes. Human and animal studies suggest that this is not benign, and that stress-induced hyperglycemia is associated with a high risk of mortality after both stroke and myocardial infarction.^[3]

Plasma glucose >120 mg/dl in the absence of diabetes is a clinical sign of sepsis.

Physiological stress

Hyperglycemia occurs naturally during times of infection and inflammation. When the body is stressed, endogenous catecholamines are released that - amongst other things - serve to raise the blood glucose levels. The amount of increase varies from person to person and from inflammatory response to response. As such, no patient with first-time hyperglycemia should be diagnosed immediately with diabetes if that patient is concomitantly ill with something else. Further testing, such as a fasting plasma glucose, random plasma glucose, or two-hour postprandial plasma glucose level, must be performed.

Measurement and definition

Glucose levels are measured in either:

1. Milligrams per deciliter (mg/dL), in the United States and other countries (e.g., Japan, France, Egypt, Colombia); or
2. Millimoles per liter (mmol/L), which can be acquired by dividing (mg/dL) by factor of 18.

Scientific journals are moving towards using mmol/L; some journals now use mmol/L as the primary unit but quote mg/dl in parentheses.^[4]

Comparatively:^[5]

• 72 mg/dL = 4 mmol/L
• 90 mg/dL = 5 mmol/L
• 108 mg/dL = 6 mmol/L
• 126 mg/dL = 7 mmol/L
• 144 mg/dL = 8 mmol/L
• 180 mg/dL = 10 mmol/L
• 270 mg/dL = 15 mmol/L
• 288 mg/dL = 16 mmol/L
• 360 mg/dL = 20 mmol/L
• 396 mg/dL = 22 mmol/L
• 594 mg/dL = 33 mmol/L

Glucose levels vary before and after meals, and at various times of day; the definition of "normal" varies among medical professionals. In general, the normal range for most people (fasting adults) is about 80 to 110 mg/dL or 4 to 6 mmol/L. A subject with a consistent range above 126 mg/dL or 7 mmol/L is generally held to have hyperglycemia, whereas a consistent range below 70 mg/dL or 4 mmol/L is considered hypoglycemic. In fasting adults, blood plasma glucose should not exceed 126 mg/dL or 7 mmol/L. Sustained higher levels of blood sugar cause damage to the blood vessels and to the organs they supply, leading to the complications of diabetes.

Chronic hyperglycemia can be measured via the HbA1c test. The definition of acute hyperglycemia varies by study, with mmol/L levels from 8 to 15.^[6]

Effects

Temporary hyperglycemia is often benign and asymptomatic. Blood glucose levels can rise well above normal for significant periods without producing any permanent effects or symptoms. However, chronic hyperglycemia at levels more than slightly above normal can produce a very wide variety of serious complications over a period of years, including kidney damage, neurological damage, cardiovascular damage, damage to the retina etc.

In diabetes mellitus (by far the most common cause of chronic hyperglycemia), treatment aims at maintaining blood glucose at a level as close to normal as possible, in order to avoid these serious long-term complications.

Acute hyperglycemia involving glucose levels that are extremely high is a medical emergency and can rapidly produce serious complications (such as diabetic ketoacidosis). It is most often seen in persons who have uncontrolled insulin-dependent diabetes.

Symptoms

The following symptoms may be associated with acute or chronic hyperglycemia, with the first three comprising the classic hyperglycaemic triad:

• Polyphagia - frequent hunger, especially pronounced hunger
• Polydipsia - frequent thirst, especially excessive thirst
• Polyuria - frequent urination, especially excessive urination
• Blurred vision
• Fatigue (sleepiness).
• Weight loss
• Poor wound healing (cuts, scrapes, etc.)
• Dry mouth
• Dry or itchy skin
• Impotence (male)
• Recurrent infections such as vaginal yeast infections, groin rash, or external ear infections (swimmer's ear)
• Kussmaul hyperventilation: deep, rapid breathing
• Cardiac arrhythmia
• Stupor
• Coma

Frequent hunger without other symptoms can also indicate that blood sugar levels are too low. This may occur when people who have diabetes take too much oral hypoglycemic medication or insulin for the amount of food they eat. The resulting drop in blood sugar level to below the normal range prompts a hunger response. This hunger is not usually as pronounced as in Type I diabetes, especially the juvenile onset form, but it makes the prescription of oral hypoglycemic medication difficult to manage.

Polydipsia and polyuria occur when blood glucose levels rise high enough to result in excretion of excess glucose via the kidneys (glycosuria), producing osmotic diuresis.

Symptoms of Diabetic Ketoacidosis may include:

• Ketoacidosis
• A decreased level of consciousness or confusion
• Dehydration due to glycosuria and osmotic diuresis
• Acute hunger and/or thirst
• 'Fruity' smelling breath odor
• Impairment of cognitive function, along with increased sadness and anxiety^[7][8]

Treatment

Treatment of hyperglycemia requires elimination of the underlying cause, e.g., treatment of diabetes when diabetes is the cause. Acute and severe hyperglycemia can be treated by direct administration of insulin in most cases, under medical supervision.

See also

• Hypoglycemia
• Diabetes
• Prediabetes

References

1. ^ Cetin M, Yetgin S, Kara A, et al. (1994). "Hyperglycemia, ketoacidosis and other complications of L-asparaginase in children with acute lymphoblastic leukemia". J Med 25 (3-4): 219–29. PMID 7996065. 
2. ^ Luna B, Feinglos MN (2001). "Drug-induced hyperglycemia". JAMA 286 (16): 1945–8. doi:10.1001/jama.286.16.1945. PMID 11667913. 
3. ^ Capes SE, Hunt D, Malmberg K, Pathak P, Gerstein HC (2001). "Stress hyperglycemia and prognosis of stroke in nondiabetic and diabetic patients: a systematic overview". Stroke 32 (10): 2426–32. doi:10.1161/hs1001.096194. PMID 11588337. 
4. ^ What are mg/dl and mmol/l? How to convert?
5. ^ Mg/dL to mmol/L Conversions
6. ^ Giugliano D, Marfella R, Coppola L, et al. (1997). "Vascular effects of acute hyperglycemia in humans are reversed by L-arginine. Evidence for reduced availability of nitric oxide during hyperglycemia". Circulation 95 (7): 1783–90. PMID 9107164. 
7. ^ Pais I, Hallschmid M, Jauch-Chara K, et al. (2007). "Mood and cognitive functions during acute euglycaemia and mild hyperglycaemia in type 2 diabetic patients". Exp. Clin. Endocrinol. Diabetes 115 (1): 42–6. doi:10.1055/s-2007-957348. PMID 17286234. 
8. ^ Sommerfield AJ, Deary IJ, Frier BM (2004). "Acute hyperglycemia alters mood state and impairs cognitive performance in people with type 2 diabetes". Diabetes Care 27 (10): 2335–40. doi:10.2337/diacare.27.10.2335. PMID 15451897. 

External links

• Hyperglycemia information - from the American Diabetes Association
• Hyperglycemia in infants - from MedlinePlus

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