Diabetes Mellitus

Question 1

what is DM?

Answer 1

a group of disorders characterized by the presence of HYPERGLYCEMIA that results from defects in SECRETION OF INSULIN OR ACTION OF INSULIN OR BOTH

Question 2

what can DM result in?

Answer 2

blindness
renal failure
CVD
stroke…

Question 3

what are the types of DM?

Answer 3

type I - insulin dependent
type II - non insulin dependent
gestational diabetes
secondary diabetes

Question 4

what is type I DM due to?

Answer 4

autoimmune destruction of beta cells of islet of pancreas - marked reduction in insulin secretion

Question 5

what is type II DM due to?

Answer 5

obesity (syndrome x/metabolic syndrome/insulin resistance syndrome)

target tissues do NOT response to circulating insulin - insulin resistant! and there is a decrease in insulin secretion over time = beta cell fatigue! (so insulin levels can be high, normal, low depending on stage of the disease)

Question 6

what is the most common cause of insulin resistance in obesity?

Answer 6

• decreased number of insulin receptors

- postreceptor failure to activate tyrosine kinase

Question 7

what may insulin resistance in obese people also be due to…?

Answer 7

• reduced adiponectin
• increase leptin (leptin resistance)
• increase free FA
• omentin
• reduced glucagon like peptide (GLP-1)

Question 8

what is omen tin?

Answer 8

protein expressed and secreted from visceral but not subcutaneous adipose tissue

plasma levels of omen tin-1 are higher in people with higher WHR

Question 9

what is GLP-1?

Answer 9

an incretin that increases insulin secretion

Question 10

what are the presenting features of DM?

Answer 10

• polydipsia
• polyphagia
• dehydration
• decreased immunity
• polyuria

Question 11

what is the classical triad of DM? more common with type I DM

Answer 11

polyuria
polydipsia
polyphagia

Question 12

why may weight loss be observed in patients with type 1?

Answer 12

accelerated lipolysis and muscle proteolysis

Question 13

what type of metabolism does DM affect?

Answer 13

protein,carb,fat

Question 14

why is there hyperglycemia with DM?

Answer 14

increase gluconeogenesis in liver
\+PEPCK
\+pyruvate carboxylase
\+ F 1,6 BP
\+ G-6-P

decreased number of GLUT 4 in peripheral tissues

both because of decreased number of insulin receptors/post receptor defects

also… decreased secretion of insulin from pancreas

Question 15

what is inhibited with low insulin and high glucagon?

Answer 15

glycolysis

glycogenesis

Question 16

where is glucose completely reabsorbed?

Answer 16

renal tubule

Question 17

why is there polyuria in DM?

Answer 17

with hyperglycemia - lots of glucose is filtered that may exceed the capacity of the tubule so now glucose is osmotically active and drags water along with it - they both leave in urine!

Question 18

what are the acute complications of DM?

Answer 18

ketoacidosis - type I
hyperosmolar non-ketotic coma - type II
hypoglycemia in DM on treatment

Question 19

what are the chronic complications of DM?

Answer 19

microvascular

macrovascular

Question 20

what are microsvascular complication of DM?

Answer 20

• neuropathy
• nephropathy
• retinophathy

occurs in tissues that do not require insulin for glucose entry - retina, nervous tissue, lens

Question 21

how can hyperglycemia result in tissue damage?

Answer 21

sorbitol formation - vision changes

Question 22

what contributes to nephropathy?

Answer 22

non-enzymatic glycation of proteins in the BM of kidney

AGEs (advanced glycation end products)

Question 23

what is the earliest sign of renal involvement in a diabetic?

Answer 23

increased loss of albumin in urine (microalbuminuria)

Question 24

what are macrovascular complications of DM?

Answer 24

atherosclerotic changes
hypertriacylglyceridemia - due to decreased action of LPL
AGEs - glycation of LDL

Question 25

what are lab tests that diagnose DM?

Answer 25

fasting BG > 126
random BG > 200
OGTT

Question 26

define pre-diabetics?

Answer 26

fasting BG of 100-125 - IFG

or

2 hour post oral glucose TT GL 140-200 –IGT

comonly associated with insulin resistance / obesity

advice dietary mod. + exercise

Question 27

what is sulonylurea?

Answer 27

increases insulin secretion from pancreas

Question 28

what is metformin?

Answer 28

decreases glucose output of liver, increases glucose utilization by muscle - improves insulin resistance