Diabetes

Question 1

Explain blood glucose homeostasis with insulin and glucagon

Answer 1

low glucose –> alpha cells of pancreas secrete glucagon –> increased gluconeogenesis, glycogenolysis, decreased glycogeneis, lipogenesis, proteogenesis –> increased glucose until homeostasis
High glucose –> beta cells of pancreas secrete insulin –> increased glucose uptake into cells, decreased glycogenolysis and gluconeogenesis –> decreased glucose until homeostasis

Question 2

Difference between diagnosis of DM with adults vs. children

Answer 2

2 or more readings: fasting blood glucose > 7.0 mmol/L, or random blood glucose > 11.1 mmol/L, or oral glucose tolerance test > 11.1 mmol/L (2 hours post)
Children: if symptomatic or > 11 mmol/L
Gestational DM if > 10.3 mmol/L for OGTT

Question 3

Explain HbA1C and weakness of it

Answer 3

% of Hgb in which glucose has been incorporated due to high blood glucose over the life of the RBC (120 days)
> 7% is positive diagnosis of DM
Weaknesses: gives average so does not indicate highs and lows
Also, because it is related to Hgb, conditions that affect RBC and Hgb will affect readings e.g. if anemic, then falsely low reading, even if blood glucose was high

Question 4

3 contributing factors to long-term complications in DM

Answer 4

1) Abnormal glycoproteins in basement membrane, vessel walls, macrophages –> structural defects
2) Increased activation of sorbitol pathway:
Glucose –> sorbitol –> fructose (normal)
but when glucose is high, sorbitol conversion to fructose is inhibited, so there is high sorbitol, which is hyperosmolar, causing increased intracellular fluid, and decreased Na/K pump activity –> peripheral neuropathy
3) chronic tissue hypoxia due to high affinity of HgbA1c to O2 –> therefore, O2 not released to tissues

Question 5

Describe the pathophysiology of DKA in Type 1 DM

Answer 5

NO insulin –> increase in blood glucose –> hyperosmolar diuresis –> dehydration and decreased blood volume –> hypotension –> shock/coma/death
also: no insulin –> proteolysis for gluconeogenesis (GNG) –> increased glucose and urea –> hyperglycemia and negative nitrogen balance –> death
also: no insulin –> lipolysis for GNG –> ketogenesis –> ketonuria causes loss of K+, Na+, phosphates –> electrolyte imbalance –> shock, coma, death
ketones also in blood –> lowers pH (acidic) –> ketoacidosis –> Kussmaul’s respirations to compensate and shock, coma, death

Question 6

Describe the pathogenesis of HHNS in Type 2 DM

Answer 6

Low insulin –> hyperglycemia –> osmotic diuresis –> dehydration and decreased blood volume –> decreased renal perfusion –> renal failure –> seizures, coma, death
osmotic diuresis and dehydration causes hemoconcentration which increases risk for thrombosis
decreased tissue perfusion causes increased anaerobic metabolism –> lactic acid (metabolic acidosis) –> CNS depression
osmotic diuresis causes hypokalemia and cardiac dysrhythmias, fluid/electrolyte imbalance which causes CNS changes
renal failure causes increased BUN and creatinine, which also contributes to metabolic acidosis
Proteolysis –> negative nitrogen balance

Question 7

3 classic manifestations of DM

Answer 7

polyuria, polydipsia, polyphagia
more pronounced in type 1 than 2
polyuria due to glucosuria - high osmotic pressure
polydipsia due to diuresis
polyphagia due to protein breakdown –> hunger

Question 8

Type 1 or 2 DM more likely to have weight loss? Weight gain?

Answer 8

Type 1: weight loss

Type 2: weight gain

Question 9

Type 1 or 2 DM more likely to have ketonuria?

Answer 9

Type 1 only because enough insulin in type 2 to not break down fats for GNG

Question 10

Type 1 or 2 DM more likely to have blurred vision?

Answer 10

Type 2 > Type 1 because of chronic exposure of lense and retina to hyperosmolar fluids - changes shape and qualities of lens

Question 11

Type 1 or 2 DM more likely to have recurrent infection?

Answer 11

Type 2 > Type 1 because defect in inflammatory cells and impairment of WBC phagocytosis

Question 12

Type 1 or 2 DM more likely to have weakness and fatigue?

Answer 12

Type 1 < Type 2

Due to potassium loss in urine and protein catabolism

Question 13

Explain the difference between Somogyi effect and Dawn phenomenon

Answer 13

Both have hyperglycemia in am (waking)
Somogyi due to counterregulatory hormones producing glucose due to EXCESS insulin administered hs vs. Dawn phenomenon as a result of hs insulin wearing off too early (decreasing duration of medication)
Somogyi effect in Type 1 DM only
Dawn phenomenon works in both Type 1 and 2
Treatment for Somogyi is decrease in insulin dose; treat Dawn phenomenon with longer acting insulin

Question 14

Emergency treatment for DKA or HHNS

Answer 14

1) IV fluids to treat dehydration (due to diuresis) until kidney perfusion at least 60 mL/hr
2) insulin bolus followed by insulin infusion with Dextrose (to prevent hypoglycemia)
3) treat electrolyte imbalances
4) when glucose stabilized, and able to tolerate PO, then go to sliding scale

Question 15

What is the onset/peak/duration of rapid-acting insulins (Lispro, Aspart, Glulisine)?

Answer 15

O: 10-15 min
P: 60-90 min
D: 3-5 hr

Question 16

What is the onset/peak/duration of short-acting insulins (Humulin R, Novolin R)

Answer 16

O: 30 min
P: 2-3 hr
D: 4-6 hr

Question 17

What is the onset/peak/duration of intermediate-acting insulins (NPH, Humulin N, Novolin N)

Answer 17

O: 1-3 hr
P: 6-8 hr
D: 12-16 hr

Question 18

What is the onset/peak/duration of long-acting insulins (Lantus, Levemir)

Answer 18

O: 1-2 hr
P: no pronounced peak
D: 12-24 hr

Question 19

Teaching for patient with DM who is ill?

Answer 19

Must continue to take insulin because stress of illness causes increase in blood glucose
Must remain hydrated and continue intake up to 15% more, including carbohydrates
Test urine for ketones
Report to physician/go to hospital if vomiting more than 2 times in 12 hours, or if ketonuria too high

Question 20

1 mmol/L of blood glucose is equal to ___?

Answer 20

20 mg of glucose

Question 21

Hyperglycemia occurs if blood sugar above ____?

Answer 21

10 mmol/L

normal 4-6 mmol/L

Question 22

Hypoglycemia occurs if blood sugar below ____?

Answer 22

4 mmol/L

normal 4-6 mmol/L

Question 23

Mild manifestations of hypoglycemia (under 4 mmol/L)

Answer 23

hunger, jitters, fatigue, weakness, irritability, sweating

Question 24

Moderate manifestations of hypoglycemia (under 3.2 mmol/L)

Answer 24

difficulty speaking, unable to stand, may have dysphagia, incoherent, irrational, combative

Question 25

Manifestations of severe hypoglycemia (under 2.8 mmol/L)

Answer 25

very agitated, unconscious, seizures

Question 26

Interventions for hypoglycemia

Answer 26

Dextrose or glucose tabs 15-20 g
15 g raises blood glucose by 2.1 mmol/L in 20 min
20 g raises blood glucose by 3.6 mmol/L in 45 min
Test blood glucose q15 minutes***
If loss of consciousness, give injectable D50W or glucagon 1 mg sc
If blood glucose > 4 mmol/L, proceed to PO snack/meal

Question 27

Macrovascular complications of DM

Answer 27

likely due to proliferation of fibrous plaques in arterial wall and increase in blood lipids:
HTN
PVD
cerebrovascular disease (e.g. CVA)
CAD
infection

Question 28

Microvascular complications of DM

Answer 28

due to thickening of capillary basement membrane and decreased tissue perfusion of microcirculation:
nephropathy
retinopathy

Question 29

Neuropathic complications of DM

Answer 29

sensorimotor e.g. stocking-glove paresthesias

autonomic neuropathy: pupillary, gastroparesis, neurogenic bladder, impotence