Diabetes: overview and type 2 Flashcards
What is diabetes?
A chronic state of hyperglycaemia caused by a lack of insulin OR a diminished effectiveness of endogenous insulin
What does insulin do?
REDUCES blood glucose
Suppresses hepatic glucose output
Increases glucose intake into insulin sensitive tissues
Increases glycogen, fat and protein formation from glucose
Suppresses lipolysis and breakdown of muscles (preventing release of glucose into blood)
Uptake of K into cells
What does glucagon do?
INCREASES blood glucose
Increases hepatic glucose output
Reduces peripheral glucose uptake
Stimulates peripheral release of gluconeogenic precursors, by lipolysis
Where are glucagon and insulin made?
In pancreas
In islets of Langerhans
Insulin in beta cells
Glucagon in alpha cells
Describe what happens in the fasting state? How are the muscles provided with enough fuel to work?
No input of glucose from food to supply the body cells
So all glucose comes from liver
- glycogen is broken down to release glucose
- gluconeogenesis, synthesis of glucose
This glucose is delivered to muscle for fuel
What is:
- glycogen
- glucagon
- gluconeogenesis?
Glycogen: storage glucose
Glucagon: hormone which increases blood glucose
Gluconeogenesis: synthesis of glucose from non-carbohydrate molecules like glycerol, pyruvate
Describe what happens in the fed state?
After eating food there’s a rapid rise in blood glucose
Some is used by the liver, some is stored as glycogen there
Some goes to muscles and is used straight away
Any excess glucose is stored as adipose or glycogen in muscles
Why do you get fat when you eat too many sugary things?
Excess glucose in the bloodstream after eating is stored as glycogen (in muscles or liver) or as adipose tissue
How can people die of diabetes?
They can get acute hyperglycaemia
If this is untreated, they can go into acute metabolic emergency, leading to organ failure, coma, death
What types of diabetes are there?
Type 1
Type 2
Medication induced Maturity onset diabetes of youth Pancreatic diabetes Endocrine diabetes Malnutrition related diabetes
What is pancreatic diabetes?
If someone has pancreatic failure due to cancer, pancreatitis etc.
Their pancreas will not be as efficient at making insulin and glucagon
Hence diabetes
Clinical features of diabetes?
Polyuria: frequent urination
Polydypsia: frequent thirst
Weight loss
Lack of energy
Which drugs can cause diabetes?
Steroids
Thiazides
How do you diagnose diabetes?
Fasting glucose > 7 mmol
and
Glucose tolerance test
OR
Random glucose > 11 mmol
OR
Hba1c: levels over 48 on 2 separate occasions
What is the glucose tolerance test?
Patient fasts
Then they are given glucose and blood samples are taken after to determine how quickly glucose is removed from the blood
The slower = diabetes
What is the cause of type 1 diabetes?
Unknown, but it is though that a viral infection triggers it.
The antibodies created against the virus begin to attack the beta cells of pancreas
Over time they get damaged so much they stop making insulin
Describe the progression of type 1 diabetes from normal healthy person to person with type 1 diabetes?
Healthy person with genetic pre-disposition to type I diabetes
Trigger, viral infection
Antibodies produced to fight virus start to attack B cells of Islets of Langerhans
This causes insulinitis: inflammation of the Islets of Langerhans, including the B cells
In time the damage to the B cells makes them stop making insulin
Pre-diabetes
Leading to diabetes
When does ketoacidosis occur?
In type 1 diabetes only
When the body cells are unable to get any glucose, because it is all stuck in the blood stream
The body starts breaking down fat to use as fuel
This means ketones are released
To many ketones can be toxic: leading to ketoacidosis
In which type of diabetes, 1 or 2 is the genetic component stronger?
Type 2
What causes type 2 diabetes?
Insulin resistance
+
Impaired insulin secretion
What are the risk factors for type 2 diabetes?
Obesity Sedentary lifestyle Family history Age Ethnicity
Pathogenesis of type 2 diabetes?
High blood sugar due to diet
Body tries to counteract this by releasing more insulin
It can’t maintain this forever so B cells in IoL get damaged and can’t maintain levels of insulin
Resistance develops to insulin
Diabetes occurs
Management of type 2 diabetes?
Lifestyle changes:
- reduce weight
- better diet
Metformin drug
Sulfonylurea
How does the drug sulfonylurea work?
By increasing insulin release from the beta cells
What is hyperosmolar hyperglycaemic state?
Very high blood glucose, occurs in type 2 diabetes
How does metformin treat diabetes?
It reduces gluconeogenesis in the liver
