Endocrine - Diabetes Flashcards
At what range of serum glucose does it start to spill into our urine?
200-250 mg/dL
What is the cellular mechanism of insulin?
Insulin stimulates the synthesis of glucose transporters which gets incorporated into cell membranes.
Insulin also activates these receptors once they are part of the cell membrane, encouraging glucose entrance into the cell for metabolic processing.
In the absence of insulin but high extracellular glucose, what happens to intracellular glucose levels?
Remains at ZERO.
Our brain cells can run on fatty acid metabolism. T/F?
False. They run on glucose only.
What metabolism-related byproduct increases in patients with DM due to their inefficient metabolism of glucose for energy?
What does this result in and how should we treat it?
Free fatty acid metabolism increases due to insufficient glucose metabolism.
This results in free fatty metabolic byproduct of aceto-acetic acid, causing metablic acidosis.
We can treat this by giving insulin, which will drive glucose into cells and decrease fatty acid metabolism (thereby improving their metabolic acidotic state).
What are the four types of DM?
Type I - Absolute insulin deficiency (juvenile onset)
Type II - Adult onset secondary to relative deficiency or desensitization
Type III - Genetic defect resulting in DM
Type IV - Gestational DM
What is Type I DM predominantly a cause of?
Destruction of pancreatic beta islet cells due to auto-immune response or immune response to a virus.
Possible genetic component.
What is Type II DM caused by?
Burning out of pancreatic islet cells in later adult life.
Can also be caused by desensitization of insulin receptors.
Compare the onset of Type I and Type II DM.
Type I - acute and short onset due to an event that usually occurs at a juvenile age.
Type II - chronic and developed over time due to environmental habits. Usually occurs in adults.
How can Type II DM patients become Type I DM patients?
If they completely burn out their pancreatic islet cells and can no longer produce any insulin at all.
What is Type IV DM (gestational) due to?
Often due to hormonal imbalances (progesterone) during pregnancy.
__% of women that experience gestational DM go on to become type II Diabetics later on in life.
30; the other 70% normalize after pregnancy is over and never develop diabetes.
What is 80% of DM etiology characterized by? 10%? The other 5 and 5%?
80%: Obese, mild, maturity-onset
10%: Non-obese, stable, adult-onset
5%: Brittle, adult-onset
5%: Juvenile onset
A small percentage of gestational diabetics require insulin. They take insulin for what ultimate purpose? (Why do they need to control their glucose?)
Control of maternal physiology and fetal development.
What kind of immune cells primarily mediate auto-immune destruction of pancreatic islet cells?
B-cells (humoral mediated immune response)
What is the upper-limit threshold glucose level for a normal adult?
~126 mg/dL
Beyond this, a fasting level indicates DM.
What is the best way to gauge a patient’s baseline glucose level?
Check their serum glucose when they are in a fasting state.
If they have just eaten, they will have a higher than usual glucose level that may not be indicative of their normal serum glucose.
What is considered a pre-diabetic state physiologically?
Islet cells have been stressed to the point of maximum insulin production and glucose levels are rising slowly as time goes on. However, islet cells have not been irreversibly damaged.
Insulin is also becoming less effective due to derangements in insulin receptor activity.
Glucose levels remain relatively steady compared to the diabetic stage.
A good percentage of DM II patients are diagnosed after their glucose levels have been out of control for a while and has caused end-organ damage already. Why?
Slow progression of DM II = symptoms are not as noticeable or easily ignored.
Describe the progression of Type 2 Diabetes by placing these factors in order:
Insulin Resistance
Increased beta cell production of insulin.
Impaired glucose tolerance
Beta cell exhaustion.
Inadequate insulin for degree of insulin resistance
Predisposing factors
Development of Type 2 DM
- Predisposing factors (obesity, sedentary lifestyle, age, etc..)
- Insulin resistance.
- Impaired glucose tolerance.
- Increased beta-cell production of insulin.
- Beta cell exhaustion.
- Inadequate insulin for the degree of insulin resistance
- Development of Type II DM.
Certain pre-disposing factors make an individual more likely to develop DM II due to burnout of beta islet cells. What are they?
Congenital
Alcoholism
Chronic presence of gall stones
Morbid obesity
Age
What tests do we adminster to diagnose DM? What are they specific threshold values?
Fasting blood glucose leveles ( >126 mg/dL )
Glucose tolerance test ( > 200 mg/dL)
Note: Glucose tolerance test is often used to test for gestational diabetes. Patient is given a glucose formulation and tested for serum glucose after 6 hours. Their blood serum of glucose should not exceed 200 mg/dL.