Hyperglycemia
Hyperglycemia | |
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Other names | High blood sugar, hyperglycemia, hyperglycæmia |
White hexagons in the image represent glucose molecules, which are increased in the lower image. | |
Specialty | Endocrinology |
Hyperglycemia is a condition in which an excessive amount of
Signs and symptoms
The degree of hyperglycemia can change over time depending on the metabolic cause, for example, impaired glucose tolerance or fasting glucose, and it can depend on treatment.[1] Temporary hyperglycemia is often benign and asymptomatic. Blood glucose levels can rise well above normal and cause pathological and functional changes for significant periods without producing any permanent effects or symptoms.[1] During this asymptomatic period, an abnormality in carbohydrate metabolism can occur, which can be tested by measuring plasma glucose.[1] Chronic hyperglycemia at above normal levels 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 or damage to feet and legs. Diabetic neuropathy may be a result of long-term hyperglycemia. Impairment of growth and susceptibility to certain infections can occur as a result of chronic hyperglycemia.[1]
Acute hyperglycemia involving glucose levels that are extremely high is a medical emergency and can rapidly produce serious complications (such as fluid loss through
The following symptoms may be associated with acute or chronic hyperglycemia, with the first three composing the classic hyperglycemic triad:[2]
- Polyphagia – frequent hunger, especially pronounced hunger
- Polydipsia – frequent thirst, especially excessive thirst
- Polyuria – increased volume of urination (not an increased frequency, although it is a common consequence)
- Blurred vision
- Fatigue
- Restlessness
- Weight loss or weight gain
- Poor wound healing (cuts, scrapes, etc.)
- Dry mouth
- Dry or itchy skin
- Tingling in feet or heels
- Erectile dysfunction
- Recurrent infections, external ear infections (swimmer's ear)
- Delayed gastric emptying
- Cardiac arrhythmia
- Stupor
- Coma
- Seizures
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.[citation needed]
Polydipsia and polyuria occur when blood glucose levels rise high enough to result in excretion of excess glucose via the kidneys, which leads to the presence of
Signs and symptoms of diabetic ketoacidosis may include:[citation needed]
- Ketoacidosis
- Kussmaul hyperventilation(deep, rapid breathing)
- Confusion or a decreased level of consciousness
- Dehydration due to glycosuria and osmotic diuresis
- Increased thirst
- 'Fruity' smelling breath odor
- Nausea and vomiting
- Abdominal pain
- Impairment of cognitive function, along with increased sadness and anxiety[3][4]
- Weight loss
Hyperglycemia causes a decrease in cognitive performance, specifically in processing speed, executive function, and performance.[5] Decreased cognitive performance may cause forgetfulness and concentration loss.[5]
Complications
In untreated hyperglycemia, a condition called
Ketoacidosis is a life-threatening condition which requires immediate treatment. Symptoms include: shortness of breath, breath that smells fruity (such as pear drops), nausea and vomiting, and very dry mouth. Chronic hyperglycemia (high blood sugar) injures the heart in patients without a history of heart disease or diabetes and is strongly associated with heart attacks and death in subjects with no coronary heart disease or history of heart failure.[7]
Also, a life-threatening consequence of hyperglycemia can be nonketotic hyperosmolar syndrome.[1]
Perioperative hyperglycemia has been associated with immunosuppression, increased infections, osmotic diuresis, delayed wound healing, delayed gastric emptying, sympatho-adrenergic stimulation, and increased mortality. In addition, it reduces skin graft success, exacerbates brain, spinal cord, and renal damage by ischemia, worsens neurologic outcomes in traumatic head injuries, and is associated with postoperative cognitive dysfunction following CABG.[8]
Causes
Hyperglycemia may be caused by: diabetes, various (non-diabetic) endocrine disorders (insulin resistance and thyroid, adrenal, pancreatic, and pituitary disorders), sepsis and certain infections, intracranial diseases (e.g. encephalitis, brain tumors (especially if near the pituitary gland), brain haemorrhages, and meningitis) (frequently overlooked), convulsions, end-stage terminal disease, prolonged/major surgeries,[9] stress,[10] and excessive eating of carbohydrates.[11]
Endocrine
Chronic, persistent hyperglycaemia is most often a result of
Diabetes mellitus
Chronic hyperglycemia that persists even in fasting states is most commonly caused by
In diabetes mellitus, hyperglycemia is usually caused by low
Ketoacidosis may be the first symptom of immune-mediated diabetes, particularly in children and adolescents. Also, patients with immune-mediated diabetes can change from modest fasting hyperglycemia to severe hyperglycemia and even ketoacidosis as a result of stress or an infection.[1]
Insulin resistance
Obesity has been contributing to increased insulin resistance in the global population. Insulin resistance increases hyperglycemia because the body becomes over saturated by glucose. Insulin resistance desensitizes insulin receptors, preventing insulin from lowering blood sugar levels.[19]
The leading cause of hyperglycemia in type 2 diabetes is the failure of insulin to suppress glucose production by glycolysis and gluconeogenesis due to insulin resistance.[20] Insulin normally inhibits glycogenolysis, but fails to do so in a condition of insulin resistance, resulting in increased glucose production.[21] In the liver, Fox06 normally promotes gluconeogenesis in the fasted state, but insulin blocks Fox06 upon feeding.[22] In a condition of insulin resistance insulin fails to block Fox06, resulting in continued gluconeogenesis even upon feeding.[22]
Medications
Certain medications increase the risk of hyperglycemia, including:
Thiazides are used to treat type 2 diabetes but it also causes severe hyperglycemia.[1]
Stress
A high proportion of patients with an acute stress such as stroke or myocardial infarction may develop hyperglycemia, even in the absence of a diagnosis of diabetes. (Or perhaps stroke or myocardial infarction was caused by hyperglycemia and undiagnosed diabetes.)[citation needed] 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.[25] Somatostatinomas and aldosteronoma-induced hypokalemia can cause hyperglycemia but usually disappears after the removal of the tumour.[1]
Stress causes hyperglycaemia via several mechanisms, including through metabolic and hormonal changes, and via increased proinflammatory cytokines that interrupt carbohydrate metabolism, leading to excessive glucose production and reduced uptake in tissues, can cause hyperglycemia.[26]
Hormones such as the growth hormone, glucagon, cortisol and catecholamines, can cause hyperglycemia when they are present in the body in excess amounts.[1]
Diagnosis
Monitoring
It is critical for patients who monitor glucose levels at home to be aware of which units of measurement their glucose meter uses. Glucose levels are measured in either:[citation needed]
- SIstandard unit used in most countries around the world.
- Milligrams per deciliter (mg/dL) is used in some countries such as the United States, Japan, France, Egypt and Colombia.
Scientific journals are moving towards using mmol/L; some journals now use mmol/L as the primary unit but quote mg/dL in parentheses.[27]
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 4 to 6 mmol/L or 80 to 110 mg/dL. (where 4 mmol/L or 80 mg/dL is "optimal".) A subject with a consistent range above 7 mmol/L or 126 mg/dL is generally held to have hyperglycemia, whereas a consistent range below 4 mmol/L or 70 mg/dL is considered
Chronic hyperglycemia can be measured via the
Defects in insulin secretion, insulin action, or both, results in hyperglycemia.[1]
Chronic hyperglycemia can be measured by
Treatment
Treatment of hyperglycemia requires elimination of the underlying cause, such as diabetes. Acute hyperglycemia can be treated by direct administration of insulin in most cases. Severe hyperglycemia can be treated with
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 serious long-term complications. This is done by a combination of proper diet, regular exercise, and insulin or other medication such as metformin, etc.[citation needed]
Those with hyperglycaemia can be treated using
Hyperglycemia can also be improved through minor lifestyle changes. Increasing aerobic exercise to at least 30 minutes a day causes the body to make better use of accumulated glucose since the glucose is being converted to energy by the muscles.[33] Calorie monitoring, with restriction as necessary, can reduce over-eating, which contributes to hyperglycemia.[34]
Diets higher in healthy unsaturated fats and whole wheat carbohydrates such as the Mediterranean diet can help reduce carbohydrate intake to better control hyperglycemia.[35] Diets such as intermittent fasting and ketogenic diet help reduce calorie consumption which could significantly reduce hyperglycemia.[citation needed]
Carbohydrates are the main cause for hyperglycemia—non-whole-wheat items should be substituted for whole-wheat items. Although fruits are a part of a complete nutritious diet, fruit intake should be limited due to high sugar content.[36]
Epidemiology
Environmental factors
Hyperglycemia is lower in higher income groups since there is access to better education, healthcare and resources. Low-middle income groups are more likely to develop hyperglycemia, due in part to a limited access to education and a reduced availability of healthy food options.[37] Living in warmer climates can reduce hyperglycemia due to increased physical activity while people are less active in colder climates.[38]
Population
Hyperglycemia is one of the main symptoms of diabetes and it has substantially affected the population making it an epidemic due to the population's increased calorie consumption.[39] Healthcare providers are trying to work more closely with people allowing them more freedom with interventions that suit their lifestyle.[40] As physical inactivity and calorie consumption increases it makes individuals more susceptible to developing hyperglycemia.[41] Hyperglycemia is caused by type 1 diabetes and non-whites have a higher susceptibility for it.[42]
Etymology
The origin of the term is Greek: prefix ὑπέρ- hyper- "over-", γλυκός glycos "sweet wine, must", αἷμα haima "blood", -ία, -εια -ia suffix for abstract nouns of feminine gender.[citation needed]
See also
References
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