Diabetes Flashcards
can we get diabetes because of eating too much sugar or too much fat?
its not so much the sugar or fat that causes diabetes, but the excess energy from eating these in excess leading to to excess weight and fat deposition
diabetes 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
characteristics of type 1 DM
- insulin dependent (IDDM)
- juvenile or growth onset
- ketosis prone [lack of insulin secretion]
characteristics of type 2 DM
- non-insulin dependent mostly
- maturity onset mostly
- not prone to ketoses
characteristics of gestational diabetes
diagnosed during pregnancy, resolved at delivery
what causes type 1 diabetes
caused by an autoimmune or idiopathic destruction of pancreatic beta-cells due to islet cell auto-antibodies (ICA) causing absolute deficiency in insulin production
- predisposition, viruses, toxins can trigger development of ICA
what causes type 2 diabetes
excessive food intake, lack of exercise, genetic predisposition -> obesity -> inflammation
- > 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 followed by beta-cell insufficiency [decreased production fo insulin]
how do you treat type 1 diabetes
insulin injection
how do you treat type 2 diabetics prone to ketosis
insulin injection
how do you treat type 2 diabetics resistant to ketosis
- diet treatment
- oral medication
- insulin injection when prolonged duration
what are some risk factors associated with diabetes
age and obesity
which populations are more at risk of diabetes?
- south asian, Asia, African, hispanic descent
- aboriginal, First Nations: 2-5 times more diabetes
- overweight, older, low income
what are the symptoms of type 1 diabetes
- increased thirst
- increased urination
- increased hunger
- weight loss or obesity
which clinical laboratory tests reveal T1 diabetes?
- glycosuria
- hyperglycemia
- abnormal glucose tolerance GTT
what are the various actions of insulin
- increased glucose uptake ans storage
- decreased glycogenolysis and gluconeogenesis = decreased endogenous glucose production
- increased lipogenesis
- decreased lipolysis
- increased protein synthesis
- decreased proteolysis
- growth/mitogenesis
- reproduction
- lifespan
- cognition
what are the general effects on insulin deficiency
There is a decrease in glucose uptake by cells, causing polyphagia, and an increase in hepatic glucose production both causing hyperglycemia -> glycosuria -> polyuria -> dehydration -> peripheral circulatory failure -> renal failure and low cerebral blood flow.
There is also decreased TG synthesis and increased lipolysis -> increased blood fatty acids -> ketosis -> metabolic acidosis > diabetic coma.
+ decreased amino acid uptake by cells [increased blood AA -> gluconeogenesis] and increased protein degradation -> muscle wasting -> weight loss
what happens metabolically in the fasted state in a diabetic patient
high lipolysis -> a lot of FA substrate for kept acids
+ high rates fo proteolysis releasing AA in circulation -> gluconeogenesis in liver -> glucose in the circulation + kept acids -> excess excreted in urine
what happens metabolically in the fed state in a diabetic patient
same as fasted start but worse: high lipolysis -> a lot of FA substrate for kept acids
+ high rates fo proteolysis releasing AA in circulation -> gluconeogenesis in liver -> glucose in the circulation + kept acids -> excess excreted in urine
++++ glucose and AA from food
what is insulin resistance
defines 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
what are the steps involved in insulin-induced glucose uptake
- in response to a rise in blood glucose, the pancreas releases more insulin into the blood
- insulin bond to a membrane-bound receipt
- the binding of insulin to its receptor signals glucose transporters to move from the cytoplasm to the cell membrane
- glucose transporters enable glucose to move from the extracellular space into the cytoplasm
what are the mechanisms that can cause insulin resistance
- receptor defects: decreased number and affinity [rare cases of genetic mutations of INSR gene]
- post-receptor second messenger signaling [most cases of IR]
what are the risk factors of type 2 diabetes
- age
- family history
- high-risk population
- prediabetes: impaired fasting glucose or impaired glucose tolerance
- history of GDM/delivery of macrosomic infant
- cardiovascular risk factors
- presence of end-organ damage associated: CV ad microvascular
- Low birth weight (<2.5kg) and high birth weight (>4.0kg)
which are the cardiovascular risk factors for T2D?
dyslipidemia, abdominal obesity, HTN, smoking, sedentary lifestyle
what are the metabolic stages of type 2 diabetes?
- pre-diabetes: obesity -> insulin resistance and impaired fasting glucose and glucose tolerance + beta-cell defect -> decreased insulin secretion
- late diabetes: beta-cell failure, non-reversible
how can pre-diabetes be reversed
with weight loss, exercise, and medication
what is the first sign of type 2 diabetes?
high fasting glucose on routine blood test
what are the common symptoms of T1D
very pronounced symptoms; wasted appearance; polyphagia, polydipsia, polyuria, HLA and islet cell antibodies present
what are the common symptoms of T2D
often not evident; usually obese; fatigue, vision changes, recent weight loss, HLA and islet cell Ab ABSENT
what has to be done to manage/stabilize type 1 diabetes
there has to be a tight matching of insulin dose and food intake
why is ketoacidosis rare in type 2 diabetes
because there is always some insulin being secreted unlike in T1D where there’s no insulin secretion/deficiency
in which case are oral antihyperglycemic agents used
in type 2 diabetes
what are some complications observed with T2D
vascular complications become evident after 5 years from diagnosis
what are some complications that can be observed with diabetes in the short term
- hypoglycaemic episodes (if treated with insulin)
- diabetic ketoacidosis (when insulin injection is forgotten - more in T1D)
- hyperglycemic hyperosmolar syndrome (more in T2D - BG>33mmol/L)
what are the early signs of hypoglycemia? and late signs?
BG<3.9mmol/L
early: neurogenic (sweating, shakiness, anxiety, sensation of hunger) and neuroglycopenic (weakness, dizziness)
late: (develop over hours) neuroglycopenic (confusion, poor coordination, blurred vision, loss of consciousness, coma
what are the common etiologies of hypoglycemia?
skipping or delaying meals, reduced CHO intake without med compensation, misdosage of insulin, unplanned exercise
why is unplanned exercise a risk factor for hypoglycemia?
exercise stimulates glucose uptake, therefore if meals are not adjusted aka high CHO intake, it can cause hypoglycemia
what is the treatment for hypoglycemia
15-15 rule
give 15g of fast absorbed CHO [fruit juice, soft drinks, glucose tablets], check blood glucose 15min later, repeat if BG is still low
if there is severe hypoglycemia, the care provider can inject _____
glucagon which stimulate endogenous glucose production, or glucose
what are some complications that can be observed with diabetes in the long term
microvascular complications:
- retinopathy: cataracts, glaucome -> blindness
- nephropathy: chronic kidney disease/failure -> dialysis, transplantation
- neuropathy: impaired sensation of pain in extremeties -> amputations
macrovascular: CVD, CHD, stroke
what causes the long term complications with diabetes
due to poorly controlled diabetes, there is a high chronic glucose level which causes protein glycation [A1c] and high lipolysis [lipotoxicity] all of which causes endothelial damage, acceleration of plaque formation and atherosclerosis => hypertension, thrombosis, ischemic end-organ damage
what is A1c
glycated hemoglobin measured as % of Hb
-> A1c is an indicator of long-term glycemic control because Hb half-life is about 3 months
what is the normal range of A1c?
4.3-6.0%
what is the effect of diabetes on dyslipidemia in type 1 diabetes?
- hypertriglyceridemia due to defective removal of chylomicrons and VLDL resulting from impaired LDL activity as LDL is insulin dependent
- HDL and LDL-c may be normal
what is the effect of diabetes on dyslipidemia in type 2 diabetes?
- hypertriglyceridemia due to elevated de novo synthesis from glucose and from FFA
- low HDL-c due to obesity
- LDL-c often elevated but may be normal