Diabetes Mellitus Flashcards
what is DM?
a group of disorders characterized by the presence of HYPERGLYCEMIA that results from defects in SECRETION OF INSULIN OR ACTION OF INSULIN OR BOTH
what can DM result in?
blindness
renal failure
CVD
stroke…
what are the types of DM?
type I - insulin dependent
type II - non insulin dependent
gestational diabetes
secondary diabetes
what is type I DM due to?
autoimmune destruction of beta cells of islet of pancreas - marked reduction in insulin secretion
what is type II DM due to?
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)
what is the most common cause of insulin resistance in obesity?
- decreased number of insulin receptors
- postreceptor failure to activate tyrosine kinase
what may insulin resistance in obese people also be due to…?
- reduced adiponectin
- increase leptin (leptin resistance)
- increase free FA
- omentin
- reduced glucagon like peptide (GLP-1)
what is omen tin?
protein expressed and secreted from visceral but not subcutaneous adipose tissue
plasma levels of omen tin-1 are higher in people with higher WHR
what is GLP-1?
an incretin that increases insulin secretion
what are the presenting features of DM?
- polydipsia
- polyphagia
- dehydration
- decreased immunity
- polyuria
what is the classical triad of DM? more common with type I DM
polyuria
polydipsia
polyphagia
why may weight loss be observed in patients with type 1?
accelerated lipolysis and muscle proteolysis
what type of metabolism does DM affect?
protein,carb,fat
why is there hyperglycemia with DM?
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
what is inhibited with low insulin and high glucagon?
glycolysis
glycogenesis
where is glucose completely reabsorbed?
renal tubule
why is there polyuria in DM?
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!
what are the acute complications of DM?
ketoacidosis - type I
hyperosmolar non-ketotic coma - type II
hypoglycemia in DM on treatment
what are the chronic complications of DM?
microvascular
macrovascular
what are microsvascular complication of DM?
- neuropathy
- nephropathy
- retinophathy
occurs in tissues that do not require insulin for glucose entry - retina, nervous tissue, lens
how can hyperglycemia result in tissue damage?
sorbitol formation - vision changes
what contributes to nephropathy?
non-enzymatic glycation of proteins in the BM of kidney
AGEs (advanced glycation end products)
what is the earliest sign of renal involvement in a diabetic?
increased loss of albumin in urine (microalbuminuria)
what are macrovascular complications of DM?
atherosclerotic changes
hypertriacylglyceridemia - due to decreased action of LPL
AGEs - glycation of LDL
