Ketones........
The Hows and Whys of Ketones
from Kathy and Cashew (GA)
--------------------------------------------------------------------------------
Energy Supplies of the Body
Before we discuss Diabetic Ketoacidosis let's review how ketones are used in the body. There are two basic forms of fuel the body uses to keep the body running at its most basic cellular level. The primary form of energy used is glucose. Glucose is obtained from digested foods (carbohydrates). Protein can also be converted to glucose in a process called gluconeogensis. Fat when digested is broken down into fatty acids and glycerol. Glycerol can also be converted to glucose. Fatty acids can used by the body or be converted to ketones. In addition to digested food, the body has reserves of fuel in the liver called glycogen, which can be converted to glucose when needed. There are also small stores of glycogen in muscle tissue. When necessary protein can be stripped from muscle mass to convert to glucose in times of extreme need. Likewise fatty acids can be converted to ketones by breaking down fat stored in adipose tissue and converting it into ketones in the cells of the liver.
Ketones: Do they deserve their bad reputation? When do they become a problem?
It may seem like ketones have a bad reputation since we've seen so many problems occur with DKA but ketones are actually used by the body everyday to provide energy to some primary body organs like the heart and can be used as an alternate energy source when glucose is lacking. They also help reserve the glucose supply for those organs that prefer it like the brain. They can be found at normal basal levels in blood and urine. When we talk about losing weight and burning fat, we are actually talking about using ketones. Dieters and people stranded in the wilderness rely on ketones to survive.
Ketones only become problematic when they replace glucose as the primary energy source. It's the excessive use of ketones which can cause the body's PH to lower and turn the blood acidic creating metabolic disorders such as diabetic ketoacidosis. When ketones have reached the level where they can be detected using urine test strips – that is the danger sign.
Who directs the body and tells it when to use which fuel?
Hormones in the body work like air traffic controllers signaling positive and negative instructions regarding its energy needs and fuel supplies. Insulin for example inhibits the production of ketone bodies by inhibiting the breakdown of fat (ljpolysis) in adipose tissue while in the liver it inhibits the conversion of free fatty acids into ketones. Glucagon, a pancreatic hormone stimulates the release of natural insulin which in turn inhibits ketone formation however in diabetics when there is either none or little supply of insulin to be stimulated, glucagon actually stimulates fat breakdown (lipolysis) in adipose tissue and enhances the conversion of fatty acids into ketones in the liver (ketogenesis) and can cause DKA. Stress hormones (catecholamines) such as epinephrine, norepinephrine, ACTH in addition to glucagon also stimulate ketone formation.
Why does DKA occur?
Diabetic Ketoacidosis occurs when glucose cannot reach the cellular level. The body tries to compensate by increasing the level of glucose in the blood. It does this by breaking down the glycogen reserve into glucose (glycogenolysis) and by creating new glucose from protein and glycerol (gluconeogensesis). The body will use whatever protein is available either from ingested food or it will strip muscle mass from the body. In a predator such as a cat the body will only strip so much muscle mass from its body since historically it knows that in order to eat, a cat must be able to walk and hunt thus promoting use of ketone formation more readily. Insulin deficiency promotes the acceleration of ketone production by stimulating fat breakdown (lipolysis). The body will try to answer the demand for fuel by breaking down more fat to convert to ketones to substitute for the lack of glucose. This causes a high level of ketones in the blood (hyperketonemia) and excessive polyuria causing dehydration and electrolyte loss and acidosis in the blood.
In an analogy I once used in an fdmb post, if the body cells were hungry guests at a party and were anxiously awaiting the pizza man (insulin) to deliver the pizza's (glucose) the host (liver) might start serving chinese food too (ketones) to placate the guests. The longer it takes the pizza man to deliver the pizzas the more chinese food gets used.
DKA prevention
To prevent DKA, all diabetic kitties should routinely be monitored for ketones in the urine using Ketostix. This will provide an early warning system so that if detected, intervention can be started before ketones progress to diabetic ketoacidosis.
Anorexia and/or insulin deficiency can lead to a lack of glucose at the cellular level which can lead to DKA. To prevent DKA a kitty must have a sufficient incoming glucose supply and must be given insulin in order to allow the glucose to enter the body cells. Anorexia is a typical sign of illness in a kitty and needs to be taken seriously with diabetic kitties because they need the glucose (even if they are currently at a high bg) to replenish their glycogen supplies. You also want your kitty to eat so you can give your kitty insulin. If a kitty refuses to eat or eats little but has a high bg and you hometest you can give a reduced dosage of insulin to move some of that glucose into the body cells and discourage ketone formation. If you don't hometest, it's more difficult to monitor the effect of a reduced insulin dosage and you have to weigh the odds of hypo risk versus ketone risk. The basic cause of the anorexia needs to be discovered. Most times DKA occurs when infection is present. This usually causes the kitty to be anorexia and the infection itself can cause bg levels to rise because of the body's greater demand for energy to fight the infection. A visit to the vet whenever anorexia lasts longer than a day is always a wise idea as well as increasing the frequency of ketone testing whenever a kitty is ill.
DKA Treatment
When a kitty is diagnosed with DKA the typical treatment involves a slow rehydration which will help flush out ketones and restore the pH level of the blood and replace electrolytes, and begin moving the body back to using glucose as its primary fuel. Usually a kitty is given fluids, electrolytes, glucose and small frequent amounts of regular insulin to facilitate glucose delivery to body cells. Antibiotics are usually given also since most times the cause is an underlying infection. When a kitty is back to eating and drinking with negative ketones they are on the road to recovery.
Sources:
aiesteves. “Re: Newly Diagnosed, With Neuropathy.” Feline Diabetes Message Board, 19 Apr. 2010, newly diagnosed, with neuropathy | Feline Diabetes Message Board - FDMB.
The Hows and Whys of Ketones
from Kathy and Cashew (GA)
--------------------------------------------------------------------------------
Energy Supplies of the Body
Before we discuss Diabetic Ketoacidosis let's review how ketones are used in the body. There are two basic forms of fuel the body uses to keep the body running at its most basic cellular level. The primary form of energy used is glucose. Glucose is obtained from digested foods (carbohydrates). Protein can also be converted to glucose in a process called gluconeogensis. Fat when digested is broken down into fatty acids and glycerol. Glycerol can also be converted to glucose. Fatty acids can used by the body or be converted to ketones. In addition to digested food, the body has reserves of fuel in the liver called glycogen, which can be converted to glucose when needed. There are also small stores of glycogen in muscle tissue. When necessary protein can be stripped from muscle mass to convert to glucose in times of extreme need. Likewise fatty acids can be converted to ketones by breaking down fat stored in adipose tissue and converting it into ketones in the cells of the liver.
Ketones: Do they deserve their bad reputation? When do they become a problem?
It may seem like ketones have a bad reputation since we've seen so many problems occur with DKA but ketones are actually used by the body everyday to provide energy to some primary body organs like the heart and can be used as an alternate energy source when glucose is lacking. They also help reserve the glucose supply for those organs that prefer it like the brain. They can be found at normal basal levels in blood and urine. When we talk about losing weight and burning fat, we are actually talking about using ketones. Dieters and people stranded in the wilderness rely on ketones to survive.
Ketones only become problematic when they replace glucose as the primary energy source. It's the excessive use of ketones which can cause the body's PH to lower and turn the blood acidic creating metabolic disorders such as diabetic ketoacidosis. When ketones have reached the level where they can be detected using urine test strips – that is the danger sign.
Who directs the body and tells it when to use which fuel?
Hormones in the body work like air traffic controllers signaling positive and negative instructions regarding its energy needs and fuel supplies. Insulin for example inhibits the production of ketone bodies by inhibiting the breakdown of fat (ljpolysis) in adipose tissue while in the liver it inhibits the conversion of free fatty acids into ketones. Glucagon, a pancreatic hormone stimulates the release of natural insulin which in turn inhibits ketone formation however in diabetics when there is either none or little supply of insulin to be stimulated, glucagon actually stimulates fat breakdown (lipolysis) in adipose tissue and enhances the conversion of fatty acids into ketones in the liver (ketogenesis) and can cause DKA. Stress hormones (catecholamines) such as epinephrine, norepinephrine, ACTH in addition to glucagon also stimulate ketone formation.
Why does DKA occur?
Diabetic Ketoacidosis occurs when glucose cannot reach the cellular level. The body tries to compensate by increasing the level of glucose in the blood. It does this by breaking down the glycogen reserve into glucose (glycogenolysis) and by creating new glucose from protein and glycerol (gluconeogensesis). The body will use whatever protein is available either from ingested food or it will strip muscle mass from the body. In a predator such as a cat the body will only strip so much muscle mass from its body since historically it knows that in order to eat, a cat must be able to walk and hunt thus promoting use of ketone formation more readily. Insulin deficiency promotes the acceleration of ketone production by stimulating fat breakdown (lipolysis). The body will try to answer the demand for fuel by breaking down more fat to convert to ketones to substitute for the lack of glucose. This causes a high level of ketones in the blood (hyperketonemia) and excessive polyuria causing dehydration and electrolyte loss and acidosis in the blood.
In an analogy I once used in an fdmb post, if the body cells were hungry guests at a party and were anxiously awaiting the pizza man (insulin) to deliver the pizza's (glucose) the host (liver) might start serving chinese food too (ketones) to placate the guests. The longer it takes the pizza man to deliver the pizzas the more chinese food gets used.
DKA prevention
To prevent DKA, all diabetic kitties should routinely be monitored for ketones in the urine using Ketostix. This will provide an early warning system so that if detected, intervention can be started before ketones progress to diabetic ketoacidosis.
Anorexia and/or insulin deficiency can lead to a lack of glucose at the cellular level which can lead to DKA. To prevent DKA a kitty must have a sufficient incoming glucose supply and must be given insulin in order to allow the glucose to enter the body cells. Anorexia is a typical sign of illness in a kitty and needs to be taken seriously with diabetic kitties because they need the glucose (even if they are currently at a high bg) to replenish their glycogen supplies. You also want your kitty to eat so you can give your kitty insulin. If a kitty refuses to eat or eats little but has a high bg and you hometest you can give a reduced dosage of insulin to move some of that glucose into the body cells and discourage ketone formation. If you don't hometest, it's more difficult to monitor the effect of a reduced insulin dosage and you have to weigh the odds of hypo risk versus ketone risk. The basic cause of the anorexia needs to be discovered. Most times DKA occurs when infection is present. This usually causes the kitty to be anorexia and the infection itself can cause bg levels to rise because of the body's greater demand for energy to fight the infection. A visit to the vet whenever anorexia lasts longer than a day is always a wise idea as well as increasing the frequency of ketone testing whenever a kitty is ill.
DKA Treatment
When a kitty is diagnosed with DKA the typical treatment involves a slow rehydration which will help flush out ketones and restore the pH level of the blood and replace electrolytes, and begin moving the body back to using glucose as its primary fuel. Usually a kitty is given fluids, electrolytes, glucose and small frequent amounts of regular insulin to facilitate glucose delivery to body cells. Antibiotics are usually given also since most times the cause is an underlying infection. When a kitty is back to eating and drinking with negative ketones they are on the road to recovery.
Sources:
aiesteves. “Re: Newly Diagnosed, With Neuropathy.” Feline Diabetes Message Board, 19 Apr. 2010, newly diagnosed, with neuropathy | Feline Diabetes Message Board - FDMB.