Ketonuria
Encyclopedia
Ketonuria is a medical condition in which ketone bodies
are present in the urine
.
It is seen in conditions in which the body produces excess ketones as an alternative source of energy. It is seen during starvation or more commonly in type I diabetes mellitus
. Production of ketone bodies is a normal response to a shortage of glucose
, meant to provide an alternate source of fuel from fatty acids.
. In healthy individuals, ketones
are formed in the liver
and are completely metabolized so that only negligible amounts appear in the urine
. However, when carbohydrates are unavailable or unable to be used as an energy source, fat
becomes the predominant body fuel instead of carbohydrates and excessive amounts of ketones are formed as a metabolic byproduct. Higher levels of ketones in the urine indicate that the body is using fat as the major source of energy.
Ketone bodies that commonly appear in the urine when fats are burned for energy are acetoacetate and beta-hydroxybutyric acid. Acetone is also produced and is expired by the lungs. Normally, the urine should not contain a noticeable concentration of ketones to give a positive reading. As with tests for glucose
, acetone can be tested by a dipstick or by a lab. The results are reported as small, moderate, or large amounts of acetone. A small amount of acetone is a value under 20 mg/dl; a moderate amount is a value of 30–40 mg/dl, and a finding of 80 mg/dl or greater is reported as a large amount.
One 2010 study admits that though ketonuria's relation to general metabolic health is ill-understood, there is a positive relationship between the presence of ketonuria after fasting and positive metabolic health.
to oral hypoglycemic
agents, the patient's urine should be monitored for ketonuria. The development of ketonuria within 24 hours after insulin withdrawal usually indicates a poor response to the oral hypoglycemic agents. Diabetic patients who use oral hypoglycemic agents should have their urine tested regularly for glucose and ketones because oral hypoglycemic agents, unlike insulin, do not control diabetes when an acute infection or other illness develops.
In conditions associated with acidosis, urinary ketones are tested to assess the severity of acidosis and to monitor treatment response. Urine ketones appear before there is any significant increase in blood ketones; therefore, urine ketone measurement is especially helpful in emergency situations. During pregnancy, early detection of ketonuria is essential because ketoacidosis is a factor associated with intrauterine death.
In nondiabetic persons, ketonuria may occur during acute illness or severe stress. Approximately 15% of hospitalized patients may have ketonuria, even though they do not have diabetes. In a diabetic patient, ketone bodies in the urine suggest that the patient is not adequately controlled and that adjustments of medication, diet, or both should be made promptly. In the nondiabetic patient, ketonuria reflects a reduced carbohydrate metabolism and an increased fat metabolism.
's brand name
for test strips to measure the level of ketone
s in the urine
. Other brands of ketone test strips are Uriscan and Atkins
. A strip consists of a thin piece of plastic film slightly larger than a matchstick, with a reagent pad on one end that is either dipped into a urine sample or passed through the stream while the user is voiding. The pad is allowed to react for an exact, specified amount of time (it is recommended to use a stopwatch to time this exactly and disregard any resultant colour change after the specified time); its resulting colour is then compared to a graded shade chart indicating a detection range from negative presence of ketones up to a significant quantity.
Ketone bodies
Ketone bodies are three water-soluble compounds that are produced as by-products when fatty acids are broken down for energy in the liver and kidney. They are used as a source of energy in the heart and brain. In the brain, they are a vital source of energy during fasting...
are present in the urine
Urine
Urine is a typically sterile liquid by-product of the body that is secreted by the kidneys through a process called urination and excreted through the urethra. Cellular metabolism generates numerous by-products, many rich in nitrogen, that require elimination from the bloodstream...
.
It is seen in conditions in which the body produces excess ketones as an alternative source of energy. It is seen during starvation or more commonly in type I diabetes mellitus
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...
. Production of ketone bodies is a normal response to a shortage of 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...
, meant to provide an alternate source of fuel from fatty acids.
Pathophysiology
Ketones are metabolic end-products of fatty acid metabolismMetabolism
Metabolism is the set of chemical reactions that happen in the cells of living organisms to sustain life. These processes allow organisms to grow and reproduce, maintain their structures, and respond to their environments. Metabolism is usually divided into two categories...
. In healthy individuals, ketones
Ketone bodies
Ketone bodies are three water-soluble compounds that are produced as by-products when fatty acids are broken down for energy in the liver and kidney. They are used as a source of energy in the heart and brain. In the brain, they are a vital source of energy during fasting...
are formed in the liver
Liver
The liver is a vital organ present in vertebrates and some other animals. It has a wide range of functions, including detoxification, protein synthesis, and production of biochemicals necessary for digestion...
and are completely metabolized so that only negligible amounts appear in the urine
Urine
Urine is a typically sterile liquid by-product of the body that is secreted by the kidneys through a process called urination and excreted through the urethra. Cellular metabolism generates numerous by-products, many rich in nitrogen, that require elimination from the bloodstream...
. However, when carbohydrates are unavailable or unable to be used as an energy source, 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...
becomes the predominant body fuel instead of carbohydrates and excessive amounts of ketones are formed as a metabolic byproduct. Higher levels of ketones in the urine indicate that the body is using fat as the major source of energy.
Ketone bodies that commonly appear in the urine when fats are burned for energy are acetoacetate and beta-hydroxybutyric acid. Acetone is also produced and is expired by the lungs. Normally, the urine should not contain a noticeable concentration of ketones to give a positive reading. As with tests for 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...
, acetone can be tested by a dipstick or by a lab. The results are reported as small, moderate, or large amounts of acetone. A small amount of acetone is a value under 20 mg/dl; a moderate amount is a value of 30–40 mg/dl, and a finding of 80 mg/dl or greater is reported as a large amount.
One 2010 study admits that though ketonuria's relation to general metabolic health is ill-understood, there is a positive relationship between the presence of ketonuria after fasting and positive metabolic health.
Screening
Screening for ketonuria is done frequently for acutely ill patients, presurgical patients, and pregnant women. Any diabetic patient who has elevated levels of blood and urine glucose should be tested for urinary ketones. In addition, when diabetic treatment is being switched from insulinInsulin
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....
to oral hypoglycemic
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"...
agents, the patient's urine should be monitored for ketonuria. The development of ketonuria within 24 hours after insulin withdrawal usually indicates a poor response to the oral hypoglycemic agents. Diabetic patients who use oral hypoglycemic agents should have their urine tested regularly for glucose and ketones because oral hypoglycemic agents, unlike insulin, do not control diabetes when an acute infection or other illness develops.
In conditions associated with acidosis, urinary ketones are tested to assess the severity of acidosis and to monitor treatment response. Urine ketones appear before there is any significant increase in blood ketones; therefore, urine ketone measurement is especially helpful in emergency situations. During pregnancy, early detection of ketonuria is essential because ketoacidosis is a factor associated with intrauterine death.
Causes of ketosis and ketonuria
- Metabolic abnormalities such as diabetes, renal glycosuriaGlycosuriaGlycosuria or glucosuria is the excretion of glucose into the urine. Ordinarily, urine contains no glucose because the kidneys are able to reclaim all of the filtered glucose back into the bloodstream. Glycosuria is nearly always caused by elevated blood glucose levels, most commonly due to...
, or glycogenGlycogenGlycogen is a molecule that serves as the secondary long-term energy storage in animal and fungal cells, with the primary energy stores being held in adipose tissue...
storage disease - Dietary conditions such as starvationStarvationStarvation is a severe deficiency in caloric energy, nutrient and vitamin intake. It is the most extreme form of malnutrition. In humans, prolonged starvation can cause permanent organ damage and eventually, death...
, fasting, high protein, or low carbohydrate diets, prolonged vomitingVomitingVomiting is the forceful expulsion of the contents of one's stomach through the mouth and sometimes the nose...
, and anorexiaAnorexia (symptom)Anorexia is the decreased sensation of appetite... - Conditions in which metabolism is increased, such as hyperthyroidismHyperthyroidismHyperthyroidism is the term for overactive tissue within the thyroid gland causing an overproduction of thyroid hormones . Hyperthyroidism is thus a cause of thyrotoxicosis, the clinical condition of increased thyroid hormones in the blood. Hyperthyroidism and thyrotoxicosis are not synonymous...
, fever, pregnancy or lactationLactationLactation describes the secretion of milk from the mammary glands and the period of time that a mother lactates to feed her young. The process occurs in all female mammals, however it predates mammals. In humans the process of feeding milk is called breastfeeding or nursing...
In nondiabetic persons, ketonuria may occur during acute illness or severe stress. Approximately 15% of hospitalized patients may have ketonuria, even though they do not have diabetes. In a diabetic patient, ketone bodies in the urine suggest that the patient is not adequately controlled and that adjustments of medication, diet, or both should be made promptly. In the nondiabetic patient, ketonuria reflects a reduced carbohydrate metabolism and an increased fat metabolism.
Test equipment
Ketostix is BayerBayer
Bayer AG is a chemical and pharmaceutical company founded in Barmen , Germany in 1863. It is headquartered in Leverkusen, North Rhine-Westphalia, Germany and well known for its original brand of aspirin.-History:...
's brand name
Brand
The American Marketing Association defines a brand as a "Name, term, design, symbol, or any other feature that identifies one seller's good or service as distinct from those of other sellers."...
for test strips to measure the level of 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 in the urine
Urine
Urine is a typically sterile liquid by-product of the body that is secreted by the kidneys through a process called urination and excreted through the urethra. Cellular metabolism generates numerous by-products, many rich in nitrogen, that require elimination from the bloodstream...
. Other brands of ketone test strips are Uriscan and Atkins
Atkins
-Places in the United States:* Atkins, Arkansas, a city* Atkins, Iowa, a city* Atkins, Virginia, a census-designated place* Atkins, Wisconsin, an unincorporated community* Atkins Peak, in Yellowstone National Park-Other uses:*Atkins...
. A strip consists of a thin piece of plastic film slightly larger than a matchstick, with a reagent pad on one end that is either dipped into a urine sample or passed through the stream while the user is voiding. The pad is allowed to react for an exact, specified amount of time (it is recommended to use a stopwatch to time this exactly and disregard any resultant colour change after the specified time); its resulting colour is then compared to a graded shade chart indicating a detection range from negative presence of ketones up to a significant quantity.
| Urine value | | Designation | | Approximate serum concentration | |
|---|---|---|---|
| mg/dL Mass concentration In astronomy or astrophysics mass concentration or mascon is a region of a planet or moon's crust that contains a large positive gravitational anomaly. In general, the word "mascon" can be used as a noun to describe an excess distribution of mass on or beneath the surface of a planet , such as Hawaii... | mmol/l | ||
| 0 | Negative | Reference range Reference range In health-related fields, a reference range or reference interval usually describes the variations of a measurement or value in healthy individuals... : 0.5-3.0 |
0.05-0.29 |
| 1+ | 5 (interquartile range Interquartile range In descriptive statistics, the interquartile range , also called the midspread or middle fifty, is a measure of statistical dispersion, being equal to the difference between the upper and lower quartiles... (IQR): 1-9) |
0.5 (IQR: 0.1–0.9) | |
| 2+ | Ketonuria | 7 (IQR: 2-19) | 0.7 (IQR: 0.2–1.8) |
| 3+ | 30 (IQR: 14-54) | 3 (IQR: 1.4–5.2) | |
| 4+ | Severe ketonuria | - | - |