Pathology of Diabetes Mellitus and Its Complications

Question 1

Which other organs is the pancreas attached to?

Answer 1

Spleen
Duodenum

Question 2

Which cells make up the endocrine part of the pancreas?

Answer 2

Islets of Langerhan cells

Question 3

2/3 of the islet cells are beta cells. What does these beta cells secrete?

Answer 3

Insulin

Question 4

What stimulates the release of insulin?

Answer 4

Eating of food->converted to glucose -> increase in blood glucose -> insulin release

Question 5

What is the pathology behind type 1 diabetes?

Answer 5

The body cannot distinguish own cells from other cells so there is an autoimmune attack on the pancreatic beta cells

Question 6

Which cells destroy the pancreatic beta cells in the autoimmune response?

Answer 6

Lymphocytes or cytotoxic T cells

Question 7

What happens when there is destruction of the islet cells?

Answer 7

Decreased secretion of insulin as beta cells undergo fibrosis and scarring and cannot produce it

Question 8

The aetiology of type 1 diabetes isn’t really known but what is it a combination of?

Answer 8

Genes and environment

Question 9

Again, the aetiology pf type 2 diabetes isn’t fully know but what is it a combination of?

Answer 9

Reduced tissue sensitivity to insulin
Inability to secrete high levels of insulin

Question 10

Describe how obesity can lead to type 2 diabetes.

Answer 10

In obesity, there are more adipocytes in the body.
This increases free fatty acids in the blood.
This leads to decreased insulin receptor sensitivity as more insulin is needed to get all the FFA ‘s into the cell

Question 11

What happens when the pancreatic beta cells are destroyed due to autoimmune destruction? (type 1 diabetes)

Answer 11

Decreased capacity to produce glucose, increasing glucose levels

Question 12

Describe how insulin secretion balance leads to type 2 diabetes.

Answer 12

Insulin secretion does not increase enough to counteract insulin resistance caused by central adiposity

Question 13

Which genes lead to type 2 diabetes?

Answer 13

Genes involved in causing inadequate ‘high level’ insulin secretion by beta cells

->not by adiposity genes causing obesity

Question 14

What reduction in life expectancy is seen in those with type 2 diabetes?

Answer 14

Life expectancy reduced by 5-10yrs

Question 15

In those with type 2 diabetes, what is the most common cause of death?

Answer 15

Myocardial infarction

Question 16

Diabetes accelerates atherosclerosis related conditions such as?

Answer 16

Coronary heart disease
MI
Atherothrombotic stroke

Question 17

How is atherosclerosis accelerated in those with diabetes?

Answer 17

Glucose attaches to a low density lipoprotein, preventing it from binding to it’s receptor
This interferes with the removal and protein and lipid, causing hyperlipidaemia
Lipids are then disposed in the vessels and this causes atherosclerosis

Question 18

Accumulation of which substances in vessels, like arterioles, is found in the vessels in those with diabetes?

Answer 18

Plasma proteins, like albumin, and connective tissue, like collagen

Question 19

What does narrowing of arterioles lead to?

Answer 19

Poor blood flow and ischaemia

Question 20

Arteriolar disease is also called hyaline change. Which parts of the body are most affected by hyaline change?

Answer 20

Kidneys
Peripheral tissue e.g. foot
Eyes

Question 21

How many times more likely is a patient with diabetes to require an amputation compared to someone who does not have diabetes?

Answer 21

40x more likely

Question 22

How many times more likely is a patient with diabetes to have end stage renal disease compared to someone who does not have diabetes?

Answer 22

25x more likely

Question 23

How many times more likely is a patient with diabetes to develop blindness compared to someone who does not have diabetes?

Answer 23

20x more likely

Question 24

How does small vessel disease occur in those with diabetes?

Answer 24

Glucoses are added to proteins- glycosylation

->initially reversible but irreversible if covalent blonds are formed

Question 25

What glycosylated collagen bind to?

Answer 25

Albumin

->normal collagen does NOT bind to albumin