Lecture 6: Diabetes Flashcards
(46 cards)
1
Q
Pancreas
A
- Pancreas is both an endocrine and an exocrine gland
- Houses the islets of Langerhans
- Secretion of glucagon and insulin
- Cells:
- Alpha—glucagon (catabolic)
- Beta—insulin (anabolic) and amylin
- Delta—somatostatin and gastrin
- F cells—pancreatic polypeptide
2
Q
Endocrine Pancreas: Insulin
A
- anabolic hormone
- Synthesized from pro-insulin
- Secretion is promoted by increased blood levels of glucose, amino acids, GI hormones
- Facilitates the rate of glucose uptake into the cells of the body
- Anabolic hormone
- Synthesis of proteins, lipids, and nucleic acids
3
Q
Endocrine Pancreas: Amylin
A
- Peptide hormone co-secreted with insulin
- Delays nutrient uptake
- Suppresses glucagon secretion
4
Q
Endocrine Pancreas ans Insulin Action on Cells
A
- Diagram showing the effective of insulin
- Glucose plays a role in anabolic process – synthesize tissues in the body
- In healthy adults – able to sit in the plasma membrane and can take glucose into the cell
- The transporter can be deferred
5
Q
Endocrine Pancreas: Glucagon
A
- Secretion is promoted by decreased blood glucose levels
- Stimulates glycogenolysis, gluconeogenesis, and lipolysis
6
Q
Diabetes
A
- Group of metabolic disorders that share a common feature of HYPERGLYCEMIA
- Type 1 DM: absolute deficiency of insulin cause by beta cell destruction- autoimmune disorder
- cells of the pancreas are attacked and destroyed (beta cells)
- Type 2 DM: combination of peripheral resistance to insulin action and inadequate secretory response
- Type 1 DM: absolute deficiency of insulin cause by beta cell destruction- autoimmune disorder
7
Q
Diabetes In Canada
A
- Diabetes prevalence is growing at epidemic levels across Canada.
- Currently, one in four Canadians have diabetes or prediabetes.
- Diabetes cost Canada $11.7 billion in 2010, and is projected to rise to $16 billion by 2020
- Complications from diabetes account for 80% of diabetes costs.
8
Q
In Canada, People with Diabetes Account For…
A
9
Q
Classification of Diabetes
A
10
Q
Diagnosis of Diabetes
A
FPG ≥7.0 mmol/L
Fasting = no caloric intake for at least 8 hours
or
A1C ≥6.5% (in adults)
Using a standardized, validated assay in the absence of factors that affect the accuracy of the A1C and not for suspected type 1 diabetes
or
2hPG in a 75 g OGTT ≥11.1 mmol/L (done for all pregnant women – sugary drink & look at glucose after a certain time period)
or
Random PG ≥11.1 mmol/L
Random = any time of the day, without regard to the interval since the last meal
11
Q
Confirmatory Test Required
A
- In the absence of symptomatic hyperglycemia, if a single lab test result is in the diabetes range, a repeat confirmatory lab test (FPG, A1C, 2hPG in a 75 g OGTT) must be done on another day
- Repeat the same test (in a timely fashion) to confirm
- But a random PG in the diabetes range in an asymptomatic individual should be confirmed with an alternate test
- If results of two different tests are available and both are above the diagnostic thresholds, the diagnosis of diabetes is confirmed
12
Q
Diagnosis of Prediabetes
A
13
Q
A1C Level and Future Risk of Diabetes: Systematic Review
A
14
Q
Definition of Metabolic Syndrome
A
- Clustering of risk factors is defined as metabolic syndrome
- Need at least three to be indicative of metabolic syndrome
15
Q
AC1 Targets
A
16
Q
Prevalence of Type 1 Diabetes
A
- 300,000+ Canadians may have T1D.
- 25% of people with T1D are diagnosed as adults.
- 10X risk of developing T1D if family has a positive history
17
Q
Type 1 Diabetes Mellitus
A
- Pancreatic atrophy and specific loss of beta cells; hyperglycemia when 80 to 90% cells lost
- Macrophages, T-cytotoxic cells, antibodies
- Alterations in insulin, amylin, glucagon
Mistakenly makes antibodies that attack the beta cells in pancreas - less insulin produced
18
Q
Genetic Susceptibility In T1D
A
- Human leukocyte antigen (HLA) region on chromosome 6
19
Q
Environmental Factors of T1D
A
- Immunologically mediated destruction of beta cells
20
Q
Pathophysiology – Type 1 Diabetes
A
- Selective loss of β cells in the endocrine pancreas
- Presence of autoantibodies against β-cell autoantigens
- Cytotoxic T Cells (e.g. CD8+ T cells) are the most predominant population within the insulitis lesion. Also:
- Macrophages (CD68+),
- CD4+ T cells,
- B lymphocytes (CD20+),
- Plasma cells (CD138+)
21
Q
Development of T1D
A
- A normal individual has a consistent beta cell mass, certain genetic predisposition + environmental factors overtime can have immune overall abnormalities
- Changes in insulin secretion and insulin tolerance can occur over months and far beyond the initial detection of the antibodies
22
Q
Treatment of T1D
A
- Pharmacological Therapy: Insulin
- BUT: Exogenous (outside of the body) insulin replacement does not always provide the metabolic regulation necessary to avoid one or more disease associated-complications (eg, retinopathy, neuropathy, CVD)
23
Q
Prevalence in T2D
A
- 10% of Canadian population
- Type II accounts for 85%-90% of all cases
- In economic terms: > $9 billion annually includes direct health care costs and those stemming from premature death and lost productivity (Health Canada)
- Epidemiological studies suggest that physical activity can reduce the risk of Type 2 diabetes by up to 50 percent (Public Health Agency of Canada)
24
Q
T2D Mellitus
A
- Ranges from insulin resistance with relative insulin deficiency to insulin secretory defect with insulin resistance
- Caused by genetic-environmental interaction
- Multiple risk factors
- Metabolic syndrome
- Initial insulin resistance
- Later loss of beta cells
- Manifestations (nonspecific): fatigue, pruritus, recurrent infections, visual changes, or symptoms of neuropathy; often overweight, dyslipidemic,hyperinsulinemic, and hypertensive
25
Risk Factors for T2D
* Age
* Gender – prominent in males
* Physical activity – 30 min/day
* Diet
* Family history
* BMI (weight/weight)
* Waist circumference
* Race/ethnicity – individuals from Asia, India have higher risk
26
Characteristics of Insulin Resistance
* Most individuals with T2D initially have insulin resistance
* Insulin resistance and beta-cell dysfunction typically precedes diagnosis of T2D
* Insulin resistance can is typically characterized by
1. Hyperglycemia
2. Dyslipidemia- high triglyceride, low HDL
3. Central obesity
4. pre-hypertension or hypertension
27
Epiology of Type 2 Diabetes
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HbA1C
* HbA1c (glycated hemoglobin) is a form of hemoglobin used primarily to identify the average plasma glucose level over prolonged periods of time
* Normal \<6.5%
* An absolute decrease of 1% in HbA1c
* 15% to 20% decrease in major cardiovascular disease events and 37% decrease in microvascular complications
29
Other Types of Diabetes Mellitus
* **Maturity onset diabetes of youth (MODY)**
* Beta-cell function or insulin action affected by autosomal dominant mutations
* **Gestational diabetes mellitus (GDM)**
* Any degree of glucose intolerance with onset or first recognition during pregnancy
30
Acute Complications of Diabetes Mellitus
* Hypoglycemia
* Diabetic ketoacidosis (DKA)
## Footnote
* when the body is nnable to use blood sugars it produces ketone bodies – has an effect on the regulation of blood pH and tends to lead to ketoacidosis*
* More common in type 1 diabetes – need to regulate their insulin injections to make sure that their sugars are within a certain range*
31
Chronic Complications
of Diabetes Mellitus
* **Microvascular disease**
* Diabetic retinopathy (in/around eyes)
* Diabetic nephropathy
* Diabetic neuropathies
* **Macrovascular disease**
* Cardiovascular disease
* Stroke
* Peripheral vascular disease
* Occlusion of vessels – causes a lot of pain
* **Infection**
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Early CV Disease
* unsulin resistance
* hypertension
* T2D
* obesity
* dyslipidemia
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Microvascular Complications
* Retinopathy
* Neuropathy
* Nephropathy
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Retinopathy
* **Diabetes is the most common cause of blindness in the US**
* Retinopathy has the highest correlation with severity and duration of diabetes
* Hyperglycemia is the primary cause of diabetic retinopathy but the specific pathophysiologic mechanisms are not well understood.
* thought to be death of microvascular contractile cells (pericytes) and the loss of intracellular contacts which leads to microaneurysms and leakage.
* Growth factors have been implicated in the development of the next phase - proliferative retinopathy.
* Vascular Endothelium Growth Factor (VGEF)
35
Classification of Diaabetic Retinopathy
* **Pre proliferative**
* increased vascular permeability
* venous dilation
* Microaneurysms
* intraretinal hemorrhage
* Fluid leakage
* Retinal ischemia.
* **Proliferative**
* Neovascularization
* Vitreous hemorrhage
* Fibrous proliferation (scarring).
36
Mechanism of Diabetic Nephropathy
* In earlier stages – hyperfiltration
* Waste products start to build up à capillaries get damaged – additional stress on kidneys when you have very high blood sugar
* Presence of protein in the urine – microalbumin urea
* Have macroalbuminuria – later and progressive renal disease and end state renal disease
* b/c protein leakage + strain in system à leads to kidney failure + failure of kidney transplant
37
Neuropathy
* Diabetic neuropathy can present as mononeuropathy or polyneuropathy and can also be divided in sensory, motor and autonomic. – pain, loss of movement, numbness
* The pathogenesis is not well elucidated, butmay be due to ischemic infarction of the peripheral nerves.
* Myelin sheath can be damaged in this case and further prevent the transmission of signals
38
Pharmacological Therapies for Diabetes
* Multiple classes of diabetes medications available
* Metformin
* Larger diabetes drugs
39
Exercise + Lifestyle Modifications For Diabetes
* 1st indication if presented with diabetes if not effective.)
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Pharmacotherapy in T2D Checklist
* CHOOSE initial therapy based on glycemia
* START with metformin +/- others
* INDIVIDUALIZE your therapy choice based on characteristics of the person with diabetes and the agent
* REACH TARGET within 3-6 months of diagnosis
41
Initial Choice of Therapy for Diabetes
42
Management of T2D
* This is the updated algorithm for management of type 2 diabetes in people with type 2 diabetes.
* At the time of diagnosis of type 2 diabetes, healthy behaviour interventions should be initiated. This is new preferred term over “lifestyle modification”. These include nutritional therapy, weight management, and physical activity. This is also an option to start metformin.
* A change from the 2013 guidelines is the next step is based on the patients individualized A1C target rather than an absolute value.
* If the A1C is less than 1.5% above the patient’s target A1C, if they are not at glycemic target within 3 months of healthy behaviour interventions, metformin should be started or increased.
* If the A1C is greater than or equal to 1.5% above target A1C, metfomin should be started immediately. A second concurrent antihyperglycemmic agent antihyperglycemic agent should be considered.
* If the patient has symptomatic hyperglycemia and/or metabolic decompensation, insulin should be initiated alone or in combination with metformin. This includes patients with dehydration, diabetic ketoacidosis or hyperosmolar hyperglycemic state.
* If the patient remains not at glycemic target, the first question to ask in choosing the second antihyperglycemic agent is whether the patient has clinical cardiovascular disease. Clinical cardiovascular disease is defined as history of myocardial infarction, coronary artery disease on angiography, unstable angina, stroke, peripheral artery disease)
* If the patient has clinical cardiovascular disease, an antihyperglycemic agent with demonstrated CV benefit should be added. This recommendation is based on several cardiovascular safety outcome studies.
43
Jardiance Reduced CV Events
* helps the kidneys get rid of glucose from the blood stream
* factors: cardiovascular death, stroke
* can prevent these effect but are still having events but are less severe
* heart failure was significantly reduced when this drug was taken
* HR is reduced to 0.86
44
Liraglutide reduced CV events
CV death, non-fatal MI, or non-fatal stroke
* Reduces CV death
* Reduces a number of factors including CV death, MI, Stroke, mortality
45
Canagliflozin reduced CV events
CV death, non-fatal MI, or non-fatal stroke
* Reduces CV death, MI, stroke, Hospital related heart failure
* Heart failure is related to diabetes
46
Therapeutic Options - Exercise
* A single exercise session has been shown to increase insulin sensitivity for **24-48 hours**
* Insulin sensitivity appears to correlate with capillarization, and increased capillary density (as well as a reduction in diffusion barriers) may also enhance positive metabolic changes in obese diabetics who exercise.
* With repeated exercise (3x/week), muscle hypertrophy (with increased glucose metabolism) and increases in VO2 max occur.
