Diabetes Flashcards
List 3 differences between Type I and Type II DM
- Type I is insulin dependant, Type II is non-insulin dependant
- Type I is defined by an absolute lack of insulin, Type II can still produce insulin but cells are less responsive
- Type I can cause ketoacidosis
What can cause a rise in blood glucose?
- Inability to produce insulin due to β cell failure or autoimmune destruction
- Insulin resistance of cells so glucose cannot be utilised
Name 4 typical symptoms of hyperglycaemia
- Polyuria
- Polydipsia
- Urogenital infections
- Blurring of vision
What are the symptoms of inadequate energy utilisation?
- Tiredness
- Lethargy
- Weakness
- Unexplained weight loss (due to increased metabolism of fatty acids)
What tests could you perform to help diagnose diabetes?
- Fasting blood glucose
- Oral glucose tolerance test
- HbA1c (Type II only)
- Need symptoms and 1 abnormal test (2 if asymptomatic) to be diagnosed
What is the advantage of performing a HbA1c test on a person with Type II DM?
- GLYCATION of Haemoglobin in RBC due to high plasma glucose
- Lifespan of RBC is ~120 days
- Gives % reading of blood glucose levels (glucose saturation) over the past 120 days
- Can monitor if diet/lifestyle modifications in Type II are effective
What are the diagnostic criteria that define diabetes?
- Fasting venous plasma glucose of >7mmol/L
- Random venous plasma glucose of >11.1mmol/L
- HbA1c of >6.5%
Why can HbA1c NOT be used to diagnose Type I diabetes?
Patients have a short history of symptoms (onset is about 2-3 weeks)
What defines Type I diabetes mellitus?
- Autoimmune destruction of β cells in islets of pancreas so no insulin production
- Insulin deficiency
- Hyperglycaemia
- Lipolysis leads to increased production of ketone bodies which can cause KETOACIDOSIS (fatal)
Explain why Type II diabetes can be as a result of insulin resistance AND insulin deficiency
- Insulin resistance of cells means glucose cannot be utilised so plasma levels rise
- β cells secrete more insulin to compensate for high blood glucose
- Eventually β cells wear out (exhaustion) which leads to relative lack of insulin
- Type II diabetics can also require the administration of insulin
List 3 factors (other than β cell failure) that can contribute to the cause of diabetes
- Drug induced e.g. Steroids
- Genetic defects of β cell or insulin action
- Pancreatitis (acute or chronic)
Explain the presentation of Type I diabetes in a patient
- Patient usually
Describe the effects of insulin on cell metabolism
- PROMOTES glycogenesis, lipogenesis, protein synthesis
- INHIBITS glycogenolysis, lipolysis, proteolysis, gluconeogenesis
Explain how insulin deficiency can lead to weight loss and ketoacidosis
- Absolute lack of insulin so cells cannot utilise glucose
- Signals stress response so lipolysis is activated to produce ketone bodies for brain metabolism (as glucose is unable to enter)
- Fat metabolised so patient loses weight
- Ketone bodies can accumulate in blood altering the buffering mechanisms and causes ketoacidosis - fatal
What factors can diagnose Type I diabetes straight away?
- Elevated venous plasma glucose >10mmol/L
- Presence of KETONES (smell acetone on breath)
- High blood pressure
- Family history
How is Type I diabetes treated?
- Exogenous insulin injections (MUST)
- Subcutaneous insulin injections several times per day
- Fluids (saline, water)
What percentage of people with Type II overweight or obese?
90%
Describe the aetiology of Type II diabetes
- Insulin resistance due to obesity
- β cell failure which leads to relative lack of insulin
- Genetic and environmental factors
Describe how obesity can lead to insulin deficiency
- First leads to insulin resistance
- Secretion of more insulin due to increase in circulating fatty acids (need to be stored)
- Pancreatic exhaustion
- Hyperglycaemia causes pancreas to secrete more insulin
- Eventually β cell failure occurs
- Can also have amyloid type deposits in islets which leads to β cell failure
Explain why diet modification is the primary treatment method for Type II diabetes
- Has been shown to drastically reduce blood glucose within a short period of time
- Coupled with moderate exercise this is very effective
- If diet changes and exercise do not work, drugs can be administered
What are the effects of a hypo-calorific diet on insulin resistance?
- Under hypo-calorific conditions fat is metabolised first from the LIVER (followed by other ectopic and subcutaneous sites)
- Decrease in fat around liver results in normal hepatic insulin sensitivity
- Glucose can slowly be utilised more so fasting glucose levels decrease
Explain why a patient presenting with Type II diabetes may not have a presence of ketones
- Still producing some insulin
- Fatty acid oxidation is inhibited by insulin so no ketones produced
Describe the presentation of a patient with Type II diabetes
- Most are >40 yrs however increasing in younger population
- Variable and slower rise in blood glucose
- Polyuria, Polydipsia, weight loss, lack of energy, persistent infections, blurred vision
- NO KETONES
- May be ASYMPTOMATIC
What happens if Type I diabetes is left untreated?
- Severe hyperglycaemia
- KETOACIDOSIS
- Coma/DEATH