Diabetes Introduction Flashcards
Diabetis mellitus definition
A metabolic disorder characterized by elevated blood glucose concentrations and disturbances of carbohydrates, lipids and protein due to defective insulin secretion and/or action.
What are the types and characteristics of diabetes
Type 1 DM
◦ Insulin-dependent (IDDM) - not used anymore
◦ Juvenile or growth onset- usually occurs before 20 yo
◦ Ketosis prone, could eventually become ketoacidosis
Type 2 DM
◦ Non-insulin dependent (mostly)
◦ Maturity onset (mostly)
◦ Not prone to ketosis due to insulin still being present
Gestational diabetes
◦ Diagnosed during pregnancy; goes away after pregnancy
- women who develop GD are more likely to develop diabetes later on in life
Other types
◦ Genetic defects
◦ Pancreatopathy
Pre-diabetes- important to address and treat
Etiology of T1DM
what is the prevalence
Autoimmune or idiopathic destruction of pancreatic ß-cells → absolute deficiency in insulin production
5-10% of all diabetes cases
Etiology of T2DM
what is the prevalence
- Cells do not respond normally to insulin (resistance)
- Cells do not take up and utilize glucose efficiently → hyperglycemia
- Pancreas may compensate or not with insulin production → hyperinsulinemia or normal levels
- 10+ years of diabetes-> insulin levels decrease
90-95% of all cases
Which type of diabetes takes longer to develop
T2Dm
Out of 90-95 of T2DM patients, how many will be ketosis resistant? Ketosis prone?
Which of those will receive insulin treatment?
85-90 Ketosis resistant
5 Ketosis prone- will require insulin treatment
Out of 85-90 Ketosis resistant T2DM patients, how many will be obese? normal weigth?
75-80% obese
5-10% normal weight
What are the treatments prescribed to all ketosis resistant T2DM patients? (no matter obese or normal)
25% Diet Rx
50% Oral medication Rx
25% Insulin Rx- at later stages of diabetes
Is diabetes more prevalent in male or female canadians?
males
corresponds with higher obesity rates in males
How did prevalnce of diabetes change from 2011? from 2013?
Increase from 2011 (but not from 2013)
What is the prevalence of diabetes in Canada?
6.7% (2.0 million) of Canadians
How did prevalence amongst sexes change in Canada?
Slight increase in prevalence in males, slight decrease in females
What is the trend in diabetes prevalence across ages?
more in men
more in older people
new casses do not develop in people aged 60-75
Diabetes in Canada: Prevalence by Province and Territory
NL, NS and ON had the highest prevalence, while NU, AB and QC had the lowest.
Which populations are at hihger risk of diabetes
◦ South Asian, Asian, African, Hispanic descent
◦ Aboriginal, First Nations: 3-5 times more diabetes
◦ Overweight, older, low income
Policies and surveillance programs in Canada that are in place to help aboriginals
◦ Canadian Diabetes Strategy
◦ Aboriginal Diabetes Initiative
◦ Canadian Chronic Disease Surveillance System
what is the link between education and obesity?
Higher prevalence in lower educated demographic
Less access to healthy food
1/_ people with diabetes
1/12 people with diabetes
how many people with diabetes are unaware of it?
1 in 2
How is diabetes a burden?
- High mortality
- High costs
Type 1 Diabetes: Causes
T1DM Symptoms
Initial observations
Clinical laboratory tests reveal:
Initial observations
◦ Increased thirst (polydipsia)
◦ Increased urination (polyuria)
◦ Increased hunger (polyphagia)
◦ Weight loss (T1DM) or obesity (T2DM); happens very rapidly
Clinical laboratory tests reveal:
◦ Glycosuria
◦ Hyperglycemia
◦ Abnormal glucose tolerance (GTT)
Why is there increased hunger?
due to increased glucose excretion in urine-> caloric lose-> increased appetite
also cells are not taking up glucose -> increased energy need signals
What are the impacts of insulin?
↑ glucose uptake and storage
↓ glycogenolysis and gluconeogenesis = ↓endogenous glucose production
↑lipogenesis
↓ lipolysis
↑ protein synthesis
↓ proteolysis
Insulin deficiency impacts
What are the cnages in usual insulin regulation in diabetes
Lypolysis occurs at higher levels due to the absence of supressing effect by insulin
Higher levels of muslce breakdown
No inhbibitory effect of insulin on gluconeogenesis in the liver
what is characteristic for the diabetic fasted state?
Increased lypolysis-> FFA are used as a main energy store
Excessive glucose levels due to high levels of gluconeogenesis and decreased uptake
High glucose levels in urine
Diabetes fed state
Type 2 Diabetes: Causes
- Excessive food intake- more that calories burned
- Lack of excercise
- Genetic predisposition
- constant Hyperinsulinemia (not only after meals, but also in fasted states) van contribute to obesity
- Compensatory Hyperinsulinemia due to excessively high levels of glucose
What is inuslin resistance and what is it mostly due to?
Defined as a lesser sensitivity to insulin’s action in suppressing hepatic glucose production and stimulating glucose uptake
Mostly due to defective insulin signaling within cells
Mechanism of insulin induced glucose uptake
Is insulin resistance cuased by the receptor?
insulin resistance mostly arises from the intercellular factors, not problems with the receptor itself
Insulin resistance: 2 cellular mechanisms
Receptor defects: decreased number and affinity
◦ Rare cases of genetic mutations of INSR gene
Post-receptor second messenger signaling
◦ Most cases of IR
Insulin signaling cascade
insulin binds to the receptors
Phosphorylation will occur
IRS (insulin receptor substarte) will get phosphorylated; after that there are 2 possible pathways:
1) ERK-1 pathway (pathway fro insulin groeth and differentiation pathway)
2) PI3K-Akt pathway is connected to more acute effects of insulin e..g after meal consumption
Impacts of Pi3K-Akt pathway
Muscle: Increased glucose tranpsport (GLUT4), Increased glycogen synthesis
Liver: Increased glycogen synthesis, Increased lipogenesis, decreased gluconeogenesis
Fat: inceased glucose transport (GLUT4), Increased lipogenesis, decreased lipolysis
Akt mTORC1 connection
Akt controlls SREBP1C activity via mTORC1
Impacts of insulin resistance on liver, muscle, blood and adipocytes
Blood: Increased blood glucose and NEFA
Muscle: decreased glucose uptake, decreased, GLUT4 expression transclocation, decreased glucose oxidation, decreased glycogenesis
Liver: Increased gluconeogenesis
Adipocytes: Increased lypolysis
Type 2 diabetes: Risk Factors
oAge
oSex (male) ?- is it sexual difference in terms of hormones or in terms of obesity?
oObesity
oSedentary lifestyle
oEthnicity (e.g. Aboriginal, African, South Asian, Hispanic)
oPrediabetes: impaired fasting glucose or impaired glucose tolerance
oFamily history
oHistory of GDM
oChild of a woman with poorly controlled diabetes during pregnancy
oLow birth weight (<2.5 kg) and high birth weight (>4.0 kg)
oPolycystic ovary syndrome (PCOS)
Insulin resistance: other related conditions
oObstructive sleep apnea
oInfection- increased infections; high BG provides nutrition for pathogens
oSteroid-induced
oCushing’s syndrome
oHemochromatosis
oLipodystrophic diabetes
oAcanthosis nigricans- results in blackening of the skin where the skin is bending
oWerner’s syndrome (adult form of progeria) oIdiopathic
Metabolic staging of type 2 diabetes
Type-2 diabetes is characterized by a progressive decrease in insulin action, followed by an inability of the β-cell to compensate for insulin resistance. Insulin resistance is the first lesion, due to interactions among genes, aging, and metabolic changes produced by obesity. Insulin resistance in visceral fat leads to increased fatty acid production, which exacerbates insulin resistance in liver and muscle. The β-cell compensates for insulin resistance by secreting more insulin. Ultimately, the β-cell can no longer compensate, leading to impaired glucose tolerance, and diabetes.
Type 1 vs. Type 2 DM
Onset
Symptoms
Control
Stability
Type 1 vs. Type 2 DM
Ketoacidosis
Oral anti- hyperglycemic agents
Insulin Tx
Diet
Complications
Diabetes Complications: Short-term (hours or days)
- Hypoglycemic episodes
- Diabetic ketoacidosis: life-threatening
- Hyperglycemic hyperosmolar syndrome
What is one of the main complications of T1DM?
Hypoglycemic episodes
Describe diabetic ketoacidosis
- More in T1DM
- ↑ risk during illness, infection, stress
- Symptoms: N/V, stomach pain, acetone breath, rapid respirations, cognitive changes; can lead to coma
- More rare than Hypoglycemic episodes
- when a person is undiagnosed, or if someone uses insulin injection and forgets to inject it or stops to inject it
- more dehydration is typical for DM-> brain is affected-> people forget to inject
Describe Hyperglycemic hyperosmolar syndrome
- More rare than Hypoglycemic episodes
- More in T2DM
- Seen with blood glucose >33 mmol/L
- excessivley high glucose levels-> hyperosmolar situation
- lost of glucose in urine-> more dehydration-> exacerbation
- Infection and dehydration are precipitating factors
What is the BG levels in hypoglycemia
BG < 3.9 mmo/L (but individual for symptoms)
What are the symptoms of hypoglycemia?
Common etiology of hypoglycemia
skipping or delaying meals, reduced CHO intake without med compensation, misdosage of insulin, unplanned exercise
the more these occur, the less sensitive people become
dangerous at night
Treatment of hypoglycemia
people sense the symotpms and need to take action as soon as they appear-> fast action required
15-15 rule: Give 15 g of fast absorbed CHO, check BG 15 min later, repeat if BG still low
What is the treatment for severe hypoglycemia?
What are the dangers of this method
treatment (from care provider): injection of glucagon or glucose
Glucagon works by telling your body to release sugar (glucose) into the bloodstream to bring the blood sugar level back up
glucagon is not stable in the solution; stress of the situation affects the impact of injection
thus, prevention is the best via education to feel the symptoms of hyperglycemia
Diabetes Complications:
Long-term aka years
Microvascular
- Retinopathy: cataracts, glaucoma, macular edema → blindness
- Nephropathy: 20-40% of persons with DM
- chronic kidney disease/failure → dialysis, transplantation
- Neuropathy: ~ 50% of persons with DM
- impaired sensation or pain in extremities → amputations
- gastroparesis: ↓peristaltis -can lead to nausea and impaired digestion
Macrovascular: CVD, CHD, stroke
Other common complications: poor wound healing, erectile dysfunction, increased susceptibility to infections
Pathophysiology of diabetes complications
What is A1C an indicator of?
A1C is an indicator of long-term glycemic control because Hb half-life is about 3 months
What is the normal levels of A1C?
Measured as a % of Hb
◦ Normal: 4.3-6.0%
T1DM and dysplididemia
◦ HyperTG due to defective removal of chylomicrons and VLDL resulting from impaired LPL activity (insulin dependent)
◦ HDL and LDL-C may be normal
T2DM and dysplididemia
◦ HyperTG due to elevated de novo synthesis from glucose
◦ Low HDL-C (due to obesity)
◦ LDL-C often elevated but may be normal
Diabetes and heart disease
oDiabetic patients have 2-4 X risk of developing CVD: greater independent risk than smoking, hypertension, hypercholesterolemia, obesity
oHeart disease is the major cause of death in DM: 65%
Recommendations for cardiovascular protection
the ABCDEs
Screening and diagnosis of T2DM in adults
FPG, OGTT, A1C, Random PG diabetes diagnosis criteria
OGTT Blood Glucose Curve
Blood glucose is measured at 2h mark
What are the 3 main markers for Diagnosis of prediabetes
oIFG
oIGT
oA1C 6.0%-6.4%
__ can prevent diabetes onset
Intervention can prevent diabetes onset
Diabetes Prevention Program (DPP)
Benefit of diet and exercise or Metformin on diabetes prevention in at-risk patients
Lifestyle changes had the biggest impact
ABCDES of diabetes care
Targets for glycemic control
Ideal, optimal, subotimal, inadequate
Non-DM, DM taget, Consider action, Action required
cut of levels for
A1C, fasting glucose, glucose 2hrs PC
__ results in reduction in incidence and progression of complications
Optimal glycemic control results in reduction in incidence and progression of complications
Which markers should be monitored in diabetes?
◦ SMBG: self-monitoring blood glucose
◦ Blood glucose
◦ Urine glucose
◦ Urine ketones
◦ Blood ketones
◦ Glycated proteins
Which device can be used for SMBG monitoring?
Glucometers
How frequently should SMBG be carried out?
Daily monitoring
- TID (2 times/day) for type 1 ((conventional Tx), more with intensive Tx
- variable for type 2
Coventional vs acute therapy
conventional therapy- fixed injection
acute- calculating dose of insulin according to CHO ingested
In which populations is SMBG especially important? In which populations it may not be necessary?
Important for people on antihyperglycemic agents or insulin to prevent hypoglycemia
May not be necessary for those only on diet Tx
