Endocrine ( 5% )

Question 1

Regarding diabetes mellitus

• Obesity results in the β cells of the islets of Langerhan becoming more responsive to decreased blood glucose.
• Obesity increases the number of insulin receptors in the insulin target organs of the body.
• Decreased sodium concentration is more important in the development of acidosis than the direct increase in ketoacids.
• Development of diabetes mellitus is unrelated to viral infection.
• Type II diabetes mellitus occurs in 60% cases.

Answer 1

Decreased sodium concentration is more important in the development of acidosis than the direct increase in ketoacids. ​

• Not specifically mentioned in R&C: just states that the dehydration impairs the ability to secrete ketones -> metabolic ketoacidosis. Does not mention the role of sodium (though hydrogen secretion is partially related to Na re-uptake).*
• It mentions that viral infection has been proposed as a cause of T1DM, but no actual evidence of this has been found.*
• Obesity results in the β cells of the islets of Langerhan becoming less responsive to decreased blood glucose.
• Obesity increases the number of insulin receptors in the insulin target organs of the body.
  
  • Obesity decreases insulin sensitivity - it seems this is partially due to impaied receptor function. I cannot find anything about a change in receptor number.
• Development of diabetes mellitus is potentially related in some cases to viral infection, though R&C states that no evidence has been found for this.
• Type II diabetes mellitus occurs in 90% of cases.

Question 2

In the pathogenesis of IDDM

• The β cell mass is normal.
• The cumulative concordance in identical twins is 20%.
• Only class I MHC molecules are involved.
• Viral infections play no role.
• 70-80% of patients have islet cell autoantibodies.

Answer 2

70-80% of patients have islet cell autoantibodies.

Anti-GAD is an example

• The β cell mass is Depleted
• The cumulative concordance in identical twins is 30-70% (cf 50-90% for type II)
• Only class II MHC molecules are involved
• Viral infections are Thought to be a possible auto-immune trigger

Question 3

IDDM

• Involves mild β cell depletion.
• Has no islet cell autoantibodies.
• Is HLA-D linked
• Has 90-100% concordance for twins.
• Has normal levels of blood insulin.

Answer 3

Is HLA-D linked

I dont care to know what this means, but the other options are all clearly wrong.

• Involves significant β cell depletion.
• Has islet cell autoantibodies.
• Has >50% concordance for twins
  
  • Type 2 has a stronger genetic component that type 1
  • Type 2 has a 90% concordance in identical twins
• Has reduced levels of blood insulin.

Question 4

type I diabetes is characterized by

• focal atrophy and amyloid deposits in islet of Langerhan.
• HLA – D linked
• No anti-islet cells antibodies
• Ketoacidosis rarely
• Onset > 30yo

Answer 4

HLA – D linked

Others are all typical of type II diabetes, the opposite occurs in type I

• focal atrophy and amyloid deposits in islet of Langerhan
  
  • Type I has destruction of beta cells by auto-antibodies
• No anti-islet cells antibodies
• Ketoacidosis rarely
• Onset > 30yo

Question 5

Type II diabetes is characterized by

• Onset in early adulthood
• 50% concordance in twins.
• severe β cell depletion.
• Islet cell antibodies.
• Normal or increased blood insulin

Answer 5

Normal or increased blood insulin

In an attempt to overcome peripheral resistence

• Onset over 40y/o
• 90% concordance in identical twins
• Mild β cell depletion
• Islet cell antibodies. - occure in Type I

Question 6

which is characteristic of type II diabetes

• early insulinitis
• not affected by pregnancy
• decreased peripheral receptor sensitivity
• less than 50% concordance in twins
• 90% of patients displaying antibodies to insulin receptors within 1 year of diagnosis

Answer 6

decreased peripheral receptor sensitivity

• Worsened by pregnancy
• >90% concordance in twins
• No antibodies in Type II diabetes

Question 7

. Diabetes is associated with

• a. Carbuncles
• b. Mucormycosis
• c. TB
• d. Gas gangrene
• e. all of the above

Answer 7

e. all of the above

Question 8

4. Pathogenesis of type 1 diabetes is associated with

• a. Decreased insulin sensitivity
• b. Abnormal glucokinase activity.
• c. No antibodies found at diagnosis
• d. Autoimmune insulinitis
• e. Twin concordance greater than 70%.

Answer 8

d. Autoimmune insulinitis

• a. Decreased insulin sensitivity - occurs in type II diabetes
• b. Abnormal glucokinase activity - occurs in MODY2
• c.Auto-antibodies found at diagnosis
• e. Twin concordance 30-50%

Question 9

12. Diabetes:

• a. A neutrophilic infiltrate “insulinitis” is observed in the islets in early diabetes
• b. GLUT2 transporters facilitate glucose entry into beta cells.
• c. Insulinitis is associated with aberrant expression of class I MHC
• e. About 40% of persons with type 1 diabetes have other autoimmune conditions, eg. Graves Disease.

Answer 9

b. GLUT2 transporters facilitate glucose entry into beta cells.

• a. A lymphocytic infiltrate “insulinitis” is observed in the islets in early diabetes
• c. Insulinitis is associated with aberrant expression of class II MHC; also non-MHC genes e.g. for insulin itself
• e. About 33% of persons with type 1 diabetes have other autoimmune conditions, eg. Graves Disease.

Question 10

13. Diabetes Mellitus:

• a. Increased hyaline arteriosclerosis.
• b. Hepatic amyloidosis
• c. Thin glomerular basement membrane.
• d. Crescentic glomerulonephritis.

Answer 10

a. Increased hyaline arteriosclerosis.

Vascular lesion associated with HTN, seen more frequently in DM

• b. Pancreatic amyloid deposits in type II
• c. Diffuse thickening of all capillary BMs
• d. Nodular glomerulosclerosis and diffuse mesangial sclerosis

Question 11

15. Type 1 diabetes

• a. Involves mild beta-cell depletion
• b. Has no islet cell autoantibodies
• c. Is HLA-D linked
• d. Has 90-100% concordance for twins
• e. Has normal levels of blood insulin

Answer 11

c. Is HLA-D linked

Others are all true for type II