Endocrinology CIS Flashcards
What happens to insulin secretion in conditions of hyperglycemia, GI hormones, and beta-adrenergic stimulation?
Increases
What happens to insulin secretion in the presence of catecholamines and somatostatin?
Decreases
Essentials of T1D diagnosis
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
Essentials of diagnosis for T2D
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
Insufficient insulin leads to reduced tissue uptake of glucose. This leads to intracellular _____ and extracellular _____
Hypoglycemia; hyperglycemia
Insufficient insulin leads to reduced tissue uptake of glucose, causing intracellular hypoglycemia. What are the downstream effects of this?
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
Insufficient insulin leads to reduced tissue uptake of glucose, causing extracellular hyperglycemia. What are the downstream effects of this?
Hyperosmotic plasma —> dehydration of cells —> hyperglycemic coma
Blood glucose exceeds renal threshold —> glucosuria —> osmotic diureses —> polyuria, polydipsia, hypokalemia, hyponatremia
What is the renal threshold for glucose?
180-200 mg/dL
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
Glycogen; GLUT4; glycolysis
______ 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.
GLUT2
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
Low; high
Insertion of GLUT2 into the ____ membrane of enterocytes induces the acute regulation of intestinal sugar absorption after a meal.
Apical
Is GLUT2 insulin-dependent?
No, GLUT2 protein itself initiates a protein signalling pathway triggering glucose signal from the PM to the transcription machinery
Is GLUT-4 insulin dependent?
Yes; it is responsible for the majority of glucose transport into muscle and adipose cells in anabolic conditions
Describe the process of osmotic diuresis
Increased BG —> increased glomerular filtration of glucose —> increased osmotic pressure of renal tubular fluid —> decreased water reabsorption —> osmotic diuresis
What are causes of high anion gap metabolic acidosis?
MUDPILES
What is high anion gap metabolic acidosis? How does diabetic ketoacidosis contribute?
In HAG metabolic acidosis, H+ is added from an extra source
In DKA, the liver produces beta-hydroxybutyric acid
How is anion gap calculated? What is normal anion gap?
Anion gap = Na - (Cl + HCO3)
Normal = 10-12 mM/L
DKA is characterized by glucose greater than _______, serum positive for ________, and metabolic acidosis with blood pH less than _______ and serum bicarb less than ______
250 mg/dL; ketones; 7.3; 15 mEq/L
The anion gap is usually due to ___________ as the charges of the other unmeasured cations and anions tend to balance out
Negatively charged plasma proteins
While calculating anion gap, it is important to adjust for ______
Hypoalbuminemia
What happens to the plasma osmolarity in conditions of hyperglycemia?
Increases, especially in the setting of osmotic diuresis
Following osmotic diuresis in conditions of hyperglycemia, ECF volume ________, leading to shock and decreased _________, eventually leading to what 3 conditions?
Decrease; GFR
Increased glucose in urine
Acidosis
Azotemia (increased BUN)
DKA can be differentiated into mild, moderate, or severe based on what factors?
Venous pH (<7.3, <7.2, <7.1)
Serum bicarb (<15 mEq/L, <10, <5)
Alteration in mental status (alert, alert/drowsy, stupor/coma)
In treating a patient with diabetic ketoacidosis, which is given first: normal saline or insulin?
NS - because it is important to deal with hyperosmolality prior to insulin administration
What is the protocol for treating abnormal potassium levels in someone presenting with DKA?
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
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?
Increased risk of cerebral edema, worsening coma, and respiratory failure
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?
Renal failure
