Introduction to Diabetes Flashcards
Define diabetes mellitus
Metabolic disorder characterized by elevated blood glucose concentrations and disturbances of carbohydrates, lipids and protein due to defective insulin secretion and/or action.
(T/F) Diabetes is only related to deregulation in CHO metabolism
FALSE - involves fats and protein
Characteristics of T1DM
- Insulin-dependent (needed for survival)
- Typically diagnosed early, prior to 20 y/o
- Ketosis prone
Why is T1DM ketosis prone?
Due to the absolute deficiency of insulin
Characteristics of T2DM
- Non-insulin dependent
- Maturity onset (diagnosed later)
- Not prone to ketosis
Why is T2DM NOT prone to ketosis?
There is NOT an absolute deficiency of insulin
(T/F) In T2DM, there is a lack of insulin
F - there is a lack of action of insulin
What is gestational diabetes? When is it resolved?
Diabetes diagnosed during pregnancy, usually resolved after the delivery of the baby
What are some other causes of diabetes?
- Genetic defects (CF)
- Pancreatopathy
(T/F) Pre-diabetes is often recognized as a real diagnosis, as it is not possible to intervene early to delay or prevent T2DM
FALSE - diagnosing prediabetes is extremely important to prevent or delay T2DM
Pathophysiology of T1DM (Brief)
Auto-immune or idiopathic destruction of pancreatic b-cells, which results in an absolute deficiency of insulin production.
-This happens QUICY (few months to a year)
Pathophysiology of T2DM (Brief)
-Calls experience insulin resistance, and are responding abnormally and will not utilize glucose efficiently, leading to hyperglycaemia.
(T/F) In T2DM, insulin resistance refers to the absence or blockage of insulin
False - insulin resistance means that the insulin signalling is not functioning as normal, and glucose is not being taken up as efficiently.
What causes hyperinsulinemia in T2DM?
When there is hyperglycaemia, the pancreas may compensate in producing more insulin (requires more insulin to reach the same basal blood glucose levels)
What happens with chronic hyperinsulinemia?
Eventually, the b-cells will start to reduce their insulin secretion
Typically, out of 100 diabetic people ____ will have T1DM and the rest will have T2DM
5-10%
Type 1 patients always require ____
Insulin treatment
Out of the patients who are T2DM and who are ketone prone will require what?
Insulin treatment
Only about 5%
____ of T2DM patients are Ketosis resistant
85-90%
Out of the ketosis resistant (No insulin Rx) T2DM patient, what % are normal weight? Obese?
10% normal weight
75-80% Obese
What will T2DM, ketosis resistant, obese and normal weight patients require as medications?
- 25% Diet Rx
- 25% Insulin Rx
- 50% Oral medication Rx
(T/F) T2DM never have insulin treatment
False, 25% typically treated with insulin
How many Canadians over 12 y/o reported being diagnosed with diabetes?
- 0 milllion
6. 7%
____ are more prevalents than ____ in terms of diabetes diagnosis
Males
Females
What increasing with age?
Incidence of diabetes
What is the most important risk factor for diabetes?
Age
What is the key point of the graph depicting diabetes increasing with age
Diabetes in both males and females drops after 12 y/o, then steadily increases. Males always more prevalent than females
Which province has the most diabetes? The least?
- Ontario, Maritimes
- Alberta
Which populations are at a higher risk for developing diabetes (while living in Canada)?
- South Asian, Asian, African, Hispanic descent
- Overweight, older and lower income individuals
Which population poses a significant higher risk (3-5x) for developing diabetes?
Indigenous populations
(T/F) The increased risk of diabetes for certain populations is primarily due to genetics
F - while genetics may have a small role, is more often related to lack of access, healthy foods, health care and nutritional education
What are very important contributors to the development of diabetes within the population?
Overweight, older and lower socioeconomic status
What is the trend of obesity and diabetes in the states?
Obesity comes first, where diabetes in the same population arrives later (Diabetes follows obesity)
A large proportion (~27.4%) of people have ____ diabetes
undiagnosed
What is the danger of living with undiagnosed diabetes?
People will live many years with uncontrolled blood sugar which can have detrimental effects
(T/F) T2DM often takes a while to diagnose
True
Currently ___ people live with diabetes, where where complications often take awhile to manifest
1/2
Causes of T1DM?
- For an unknown cause, body will begin to produce islet cell auto-antibodies
- These auto-antibodies will destroy the B-cells, causing injury and decreasing levels of insulin and eventually inhibiting any insulin secretion.
What are some triggers that are considered to begin the production of auto-antibodies?
- Genetic predisposition (unsure of the actual gene)
- Environmental triggers, such as virus, toxins and stress
Symptoms of T1DM?
-Polydipsia, polyuria, polyphagia, weight loss
Symptoms of T2DM?
-Polydipsia, polyuria, polyphagia, weight-gain
(T/F) Symptoms are much more severe in T2DM
False, much more severe in T1DM
What will clinical lab values show in both T1 and T2 DM?
- Glycosuria
- Hyperglycemia
- Abnormal glucose tolerance
What actions does insulin increase?
- Increase glucose uptake and storage
- Increase lipogenesis
- Increase protein synthesis
What actions does insulin decrease?
- Decrease glycogenolysis and gluconeogenesis (endogenous glucose production)
- Decreased lipolysis
- Decreased proteolysis
What is the main role of insulin in the liver?
Glucose production
(T/F) In the liver, insulin has less or a role in the regulation of glucose
T
While liver controls glucose production under the influence of insulin, what are insulins effects on heart, adipose and muscle?
Stimulate glucose intake (GLUT4 dependent)
(T/F) Insulin will stimulate hepatic uptake of glucose
False, as liver is not GLUT4 dependant
Explain the effects of insulin deficiency on glucose metabolism
- Higher hepatic endogenous production of glucose + no glucose uptake into cells = hyperglycemia.
- Cells feel starved, and will signal hunger (polyphagia)
- Glucose threshold is reached in blood, spill-over into the kidney (polyuria)
What are the long-term effects of uncontrolled diabetes on glucose metabolism?
Will lead to polyuria and dehydration.
What may dehydration lead to? (3) Which ones lead to death?
- Polydipsia
- Cellular shrinking which could lead to nervous system malfunction (death)
- Decrease in blood volume which could lead to renal failure, low cerebral blood flow (death)
Explain the effects of insulin deficiency on lipid metabolism
- Less lipogenesis and less synthesis of TGs from dietary fat, promoting lipolysis.
- Increase in FFA in bloodstream will be alternative source of fuel, leading to ketosis.
Is the ketosis caused by insulin deficiency (lipid metabolism) dangerous?
- In a healthy person, ketosis is not dangerous however in a diabetic person may develop into metabolic acidosis if prolonged.
- Levels of ketones may be seen 10x as high than normal ketosis (if uncontrolled)
What are the effects of the high levels of ketone bodies caused by insulin deficiency (lipid metabolism) ?
- Increased ventilation to excrete CO2 (acidic)
- Decrease pH and metabolic imbalances could eventually lead to diabetic coma.
When are most people diagnosed with T1DM?
After an episode of diabetic coma
Effects of insulin deficiency on protein metabolism?
-Less AA uptake by the cells, and increased protein catabolism –> Muscle wasting and weight loss
How do all the macromolecules contribute to hyperglycaemia?
Due to the catabolic state, glycerol (from TG) and gluconeogenic AA will participate in gluconeogenesis, further aggravating the hyperglycaemic state.
What happens in the exacerbated fasted state due to a lack of insulin? (fuel flux)
- Full blown lipolysis, where large amount of FFA in blood, and glycerol –> glucoe.
- Increases proteolysis, used in gluconeogenesis or protein catabolism (neg nitrogen balance)
What are the main sources of fuels in the exacerbated fasted state?
Glucose is being produced at it’s highest rate alongside the production of keto acids from the liver.
In T1DM, the person is better off ____ than eating
fasting
How does the fed state aggravate the fuel flux?
Recall that a already amount of glucose and keto acids are already being produces, and protein catabolism increases.
- Lack of insulin means that we are further aggravating the hyperglycaemic state in the bloodstream
- Glucose not taken up, protein not used for pro synthesis and lipids are catabolized
(T/F) In the fed state, some of the excess glucose will be synthesized into glycogen in T1DM
False, as insulin is deficient
How is T1DM often rapidly diagnosed? How is someone relived from a diabetic coma?
- Blood sugar ~25 mmol/L
- Immediate infusion of IV insulin, electrolytes (Na+/K+)
What is a major cause of T2DM?
Obesity, often from excessive food intake, lack of PA, some genetic predisposition
Explain the vicious cycle of insulin resistance and obeisty
Obesity can cause insulin resistance, which will lead to hyperglycemia and hyperinsulinemia. The excess insulin may cause further weight gain, aggravating obesity.
What associated with obesity may also contribute to insulin resistance?
Inflammation, as there is low-grade inflammation on obesity
What does insulin resistance lead to ? (2)
- Hyperglycemia
- B-cell decompensation
What can genetic predisposition influence?
- Obesity
- Insulin resistance
- B-cell decompensation
Over time, what will aggravate B-cell decompensation, eventually leading to T2DM?
- Insulin resistance
- Hyperglycaemia
- Lipotoxicity, inflammation
- Some genetic predisposition
We know that intake of sugar that does not lead to weight gain, is NOT the cause for diabetes. However, what may influence insulin resistance?
High fructose corn syrup from soft-drinks can contribute to insulin resistance even when consumed within energy balance.
(T/F) We could develop diabetes on a high fat diet
T
Explain why when insulin resistance is diagnosed, it is not yet indicative of T2DM
The hypersinsulinemia will work to control blood glucose
When do we officially develop diabetes?
When there is B-cell destruction and the pancreas can no longer compensate with increased insulin secretion
What is lipotoxicity?What can is lead to?
- High level of lipids within the circulation which impacts cell function and inflammation
- B-cell decomposition
Define insulin resistance
Lesser sensitivity to insulin actions in suppressing hepatic glucose production and stimulating glucose uptake