Endo Quiz

Question 1

How is normal glucose homeostasis maintained?

Answer 1

• Depends on secretion of insulin
• Insulin is secreted from pancrease in response to food
• Insulin signals to cells around the body that they should start using glucose (especially muscle and liver)
• In normal people, glucose levels hardly change due to insulin

Question 2

What occurs on the cellular level when insulin is secreted from the pancreas?

Answer 2

Glucose goes to the pancrease

Insulin is secreted from the pancreas

Insulin binds to receptor

This turns on GLUT-4 pump

GLUT-4 pumps glucose into muscle and fat cells

• also pumps in potassium and phosphate

Question 3

What are the functions of insulin?

Answer 3

• Signal that you have been fed
• Switches on all pathways that use up glucose and store glycogen and fat
• Glycogen Synthase in liver and muscle turned on
• Glycolysis in liver and muscle turned on
• Gluconeogenesis switched off (making glucose from protein)

Question 4

What happens to insulin levels during starvation?

Answer 4

Insulin levels fall

Substrates available:

• glucose
• then glycogen (liver glycogen lasts 24 hours)
• then triglycerides
• then protein

Question 5

What fuel does the brain use in starvation?

Answer 5

Fall in blood glucose

Insulin levels fall

Liver switches on ketogenesis

Ketones can cross the BBB

Question 6

What is the pathology of T1DM?

Answer 6

The immune system destroys the islets of Langerhans in the pancreas

There is resultant total deficiency of insulin

All cells of the body therefore fail to take up glucose

Plasma glucose therefore rises

Glucose leaks into the uria (glycosuria)

Large volumes of urine result

COMPLETE INSULIN DEFICIENCY CAUSES ACIDOSIS

• Body starts to make ketones due to low/no insulin
• Ketones build up
• Ketones are midly acidic

Question 7

What is the peak incidence age of T1DM?

Answer 7

12-14 years old

Peak in February due to increase in viral infection incidence

Question 8

Why can total absence of insulin cause death?

Answer 8

When insulin levels are zero, the liver behaves wrongly as there is no fuel for the brain to keep working

Therefore, the liver makes lots of ketones (acids)

The blood turns acidic with ketones in the urine

The brain cannot function in an acid pH

Question 9

What are some of the signs and symptoms of Diabetic Ketoacidosis?

Answer 9

High blood glucose

• as it cannot get into cells

High ketones in blood

• acidic blood pH

Severe dehydration

• stop drinking
• glycosuria

Air hunger

• deep sighing
• to get rid of CO₂
• in order to bring pH back up

Question 10

How do you treat Diabetic Ketoacidosis?

Answer 10

Rehydrate with normal saline

Intravenous insulin infusion

Question 11

How is T1DM treated?

Answer 11

Insulin

Diet

Reduce risk factors for retinopathy, nephropathy and neuropathy

Question 12

Why does insulin resistance occur in T2DM?

Answer 12

The mechanism is still incompletely understood

Cells does not respond to insulin

GLUT-4 is only partly activated

Question 13

What does ketogenesis not typically occur in T2DM?

Answer 13

This stimulus for ketogenesis is a fall in insulin level

T2DM still have insulin so this turns off ketogenesis

Question 14

What is the pathology of T2DM?

Answer 14

• Resistance to insulin action
• Only partial activation of GLUT-4 receptors
• Secondary rise in glucose
• Pancrease makes lots of insulin to try and counteract this
• Eventually, after years, the pancreas becomes exhausted
• T2DM ensues

Question 15

What are some of the signs and symptoms of T2DM?

Answer 15

• Usually older (e.g. 60 years old)
• Usually overweight or obese
• Polyuria
• Polydipsia
• Not ketotic
• Eventually Hyper Osmolar Non Ketotic Coma (HONKC)

Question 16

How do you manage T2DM?

Answer 16

• Rehydrate with normal saline SLOWLY for people with HONKC
• Lose weight
• Avoid sugar
• Slow absorption of carbohydrate (high fibre diet)
• Make yourself more sensitive to insulin (Biguanide: Metformin)
• Insulin or other drugs (sulphonylureas like gliclazide) that stimulate your pancreas a bit more

Question 17

What is the diagnosis in a patient with:

• Fasting Glucose = 7.7 mM
• Following Glucose Tolerance Test = 7.7 mM

Answer 17

Either T1DM or T2DM

More likely to be T2DM

Question 18

What classes of drugs for diabetes are there?

Answer 18

1. Thiozolidinediones (Pioglitazone)
2. Biguanide (Metformin)
3. Sulphonylurea (Glicazide, Glibenclamide)
4. Incretins (GLP-1 analogues, exanatide)
5. Dipeptidyl peptidase IV inhbitors (gliptins)
6. Gliflozins (SGLT2 inhibitors like Dapagliflozin)
7. Insulin

Question 19

What other treatment is more effective than metformin at preventing diabetes?

Answer 19

Diet and Exercise