Endocrinology CIS

Question 1

What happens to insulin secretion in conditions of hyperglycemia, GI hormones, and beta-adrenergic stimulation?

Answer 1

Increases

Question 2

What happens to insulin secretion in the presence of catecholamines and somatostatin?

Answer 2

Decreases

Question 3

Essentials of T1D diagnosis

Answer 3

Polyuria, polydipsia, and weight loss associated with random plasma glucose of 200 mg/dL or more

Plasma glucose of 126 or more after an overnight fast on multiple occasions

Ketonemia, ketonuria, or both

Islet autoantibodies frequently present

Question 4

Essentials of diagnosis for T2D

Answer 4

Many age 40+ and obese

Polyuria, polydipsia. Ketonuria and weight loss generally uncommon at time of dx. Candidal vaginitis in women may be initial manifestation. Many patients have few or no symptoms

Plasma glucose of 126 or more after overnight fast on multiple occasions. Two hours after 75 g oral glucose, diagnostic values are 200 mg/dL or more

HbA1c 6.5% or more

HTN, dyslipidemia, and atherosclerosis are often associated

Question 5

Insufficient insulin leads to reduced tissue uptake of glucose. This leads to intracellular _____ and extracellular _____

Answer 5

Hypoglycemia; hyperglycemia

Question 6

Insufficient insulin leads to reduced tissue uptake of glucose, causing intracellular hypoglycemia. What are the downstream effects of this?

Answer 6

Glucogenesis and gluconeogenesis

Breakdown of fats —> high levels of ketones —> DKA

Decreased protein synthesis —> cachexia, lethargy, polyphagia

Decreased gamma globulins —> susceptibility to infections, impaired wound healing

Question 7

Insufficient insulin leads to reduced tissue uptake of glucose, causing extracellular hyperglycemia. What are the downstream effects of this?

Answer 7

Hyperosmotic plasma —> dehydration of cells —> hyperglycemic coma

Blood glucose exceeds renal threshold —> glucosuria —> osmotic diureses —> polyuria, polydipsia, hypokalemia, hyponatremia

Question 8

What is the renal threshold for glucose?

Answer 8

180-200 mg/dL

Question 9

Effects of insulin on glucose uptake and metabolism:

Insulin binds its receptors —> protein activation cascades —> ______ synthesis —> translocation of ____ transporter to PM and influx of glucose —> _________ —> triglyceride

Answer 9

Glycogen; GLUT4; glycolysis

Question 10

______ is a facilitative glucose transporter located in the PM of the liver, pancreatic, intestinal, kidney cells as well as in the portal and hypothalamus areas.

Answer 10

GLUT2

Question 11

GLUT2 has ____ affinity and _____ capacity; transporting dietary sugars, glucose, fructose, and galactose in large range of physiological concentrations, displaying large bidirectional fluxes in and out of cells

Answer 11

Low; high

Question 12

Insertion of GLUT2 into the ____ membrane of enterocytes induces the acute regulation of intestinal sugar absorption after a meal.

Answer 12

Apical

Question 13

Is GLUT2 insulin-dependent?

Answer 13

No, GLUT2 protein itself initiates a protein signalling pathway triggering glucose signal from the PM to the transcription machinery

Question 14

Is GLUT-4 insulin dependent?

Answer 14

Yes; it is responsible for the majority of glucose transport into muscle and adipose cells in anabolic conditions

Question 15

Describe the process of osmotic diuresis

Answer 15

Increased BG —> increased glomerular filtration of glucose —> increased osmotic pressure of renal tubular fluid —> decreased water reabsorption —> osmotic diuresis

Question 16

What are causes of high anion gap metabolic acidosis?

Answer 16

MUDPILES

Question 17

What is high anion gap metabolic acidosis? How does diabetic ketoacidosis contribute?

Answer 17

In HAG metabolic acidosis, H+ is added from an extra source

In DKA, the liver produces beta-hydroxybutyric acid

Question 18

How is anion gap calculated? What is normal anion gap?

Answer 18

Anion gap = Na - (Cl + HCO3)

Normal = 10-12 mM/L

Question 19

DKA is characterized by glucose greater than _______, serum positive for ________, and metabolic acidosis with blood pH less than _______ and serum bicarb less than ______

Answer 19

250 mg/dL; ketones; 7.3; 15 mEq/L

Question 20

The anion gap is usually due to ___________ as the charges of the other unmeasured cations and anions tend to balance out

Answer 20

Negatively charged plasma proteins

Question 21

While calculating anion gap, it is important to adjust for ______

Answer 21

Hypoalbuminemia

Question 22

What happens to the plasma osmolarity in conditions of hyperglycemia?

Answer 22

Increases, especially in the setting of osmotic diuresis

Question 23

Following osmotic diuresis in conditions of hyperglycemia, ECF volume ________, leading to shock and decreased _________, eventually leading to what 3 conditions?

Answer 23

Decrease; GFR

Increased glucose in urine

Acidosis

Azotemia (increased BUN)

Question 24

DKA can be differentiated into mild, moderate, or severe based on what factors?

Answer 24

Venous pH (<7.3, <7.2, <7.1)

Serum bicarb (<15 mEq/L, <10, <5)

Alteration in mental status (alert, alert/drowsy, stupor/coma)

Question 25

In treating a patient with diabetic ketoacidosis, which is given first: normal saline or insulin?

Answer 25

NS - because it is important to deal with hyperosmolality prior to insulin administration

Question 26

What is the protocol for treating abnormal potassium levels in someone presenting with DKA?

Answer 26

Do not start replacing K until closer to 4 and acidosis starts to move toward normal, because as you correct the acidosis the K will begin to normalize

Question 27

When treating DKA, glucose levels are usually reduced to about 200-250 and held there while volume repletion continues. What happens when you correct too quickly?

Answer 27

Increased risk of cerebral edema, worsening coma, and respiratory failure

Question 28

NaHCO3 is usually not needed in the treatment of DKA. Patients with what condition might require a bicarb drip in order to normalize their acid/base status?

Answer 28

Renal failure