Flashcards in Diabetes, Glucose and Pancreatitis Deck (56)
What pancreas cells have the exocrine function?
acinar cells secreting pancreatic enzymes into pancreatic ducts
What pancreas cells have the endocrine function?
islets of langerhan cells secreting hormones into blood vessels
What are the pancreatic enzymes?
alkaline fluid with bicarb and digestive enzymes:
amylolytic enzymes like amylase
What are the three main endocrine hormones made by the pancreas?
What cells produce insulin?
What cells produce glucagon?
What cells produce somatostatin?
Describe the changes from preproinsulin to insulin.
starts as preproinsulin, then the signal peptide is removed to make prosinulin, then the c-peptide is removed leaving just the A and B chain of insulin
What blood sugar is considered hypoglycemic in patients without diabetes? How about with diabetes?
Without diabetes: less than 40 mg/dL (although symptoms usually kick in at less than 55)
Less than 70 in diabetis
What is Whipple's Triad (and why do we care about it)?
We care about it because if you meet the criteria for the triad, then you need to do a hypoglycemia workup for a non-diabetic patient
1. recognize symptoms that could be caused by hypoglycemia
2. Document that the plasma glucose concentrations are low when the symptoms are present
3. show the symptoms can be relieved with administration of glucose
What is the differential diagnosis for hypoglycemia?
Drug-induced (most common cause--includes alcohol)
endogenous hyperinsulinism (insulinoma, sulfonylurea/glinide use, insulin autoimmune hypoglycemia)
accidental/maligious or surrepticious hypoglycemia (munchausen's)
pseudohypoglycemia (wrong tube used)
After Whipple's triad is confirmed, what additional tests should be ordered?
sulfonylura and glinide screen
after treating the acute phase, patient should undergo a supervised fast until symptom recurrence or 72 hrs
If someone's glucose is less than 55 mg/dl, what shuould their insulin be?
less than 3 mU/l
What is the only diagnosis that would cause a combination of elevated insulin level and low c-peptide level?
injection of insulin (because endogenous insulin would also cause c-peptide to be high)
What are the current diagnostic criteria for diabetes?
1. fasting plasma glucose over 126 mg/cL
2. HbA1c > 6.5%
3. 2-hr value in an OGTT over 200 mg/dL
4. Random plasma glucose concentration over 200 mg/dL WITH symptoms
If you run two tests for diabetes and the results are discordant, which test should be repeated?
the one that was diagnostic of diabetes
Which of the diagnostic criteria are now primarily recommended for the diagnosis of diabetes?
A1c over 6.5%
more convenient bc no fasting and there is correlation with retinopathy
At what A1c level does retinopathy increase?
HbA1c is indicative of glucose control over 3 months. What other lab tests can be used as indicators of glucose control over a period of time?
Fructosamine (nonenzymatic glycation of glucose to the alpha terminus of proteins like albumin): 1-2 weeks
1,5-anhydroglucitol (renal absorption of this is inhibited by glucose, so measurements reflect blood glucose level over last 24 hrs - higher levels suggest higher blood glucose levels)
In what situations are HbA1c results not reliable?
hemoglobinopathies (if they don't have any hemoglobin A, they obviously won't have an A1c)
Hemolysis (shortened RBC lifespan will lower A1c)
Polycythemia or post-splenectomy (longer RBC lifespan will falsely elevate)
If the HbA1c is going to be unreliable in a given patient, what is the recommended alternative test?
What are the two entities that are of greatest concern in a diabetic with severe hyperglycemia and coma?
DKA and HHS
What lab tests should be ordered to differentiate between DKA and HHS?
UA with urine ketones
serum ketones (if urine ketones are present)
Arterial blood gas (if urine ketones or anion gap present)
Which one (DKA or HHS) tends to occur at higher BS levels?
HHS is usually over 600 (and can exceed 1000)
DKA criteria are over 250 and will usually be less than 800
Which one will have a lower pH
The names give it away - DKA
Which one will have elevated urine and serum ketones?
DKA ( for the most part - HHS may have small amounts just due to dehydration)
Which one will have elevated serum osmolality for sure?
Again, the name gives it away - HHS will have an osmolality above 320 mOsm/kg
DKA is variable
Which one will have an elevated anion gap for sure?
DKA (HHS will be variable)
Which type of diabetics are more likely to get DKA and which are more likely to get HHS?
Type 1 - DKA
Type 2 - HHS