Diabetes Mellitus Flashcards
What is the definition of DM?
A group of metabolic diseases of multiple aetiologies characterised by hyperglycaemia together with disturbances of carbohydrate, fat and protein metabolism resulting from defects in insulin secretion, insulin action, or both
What are six symptoms of hyperaemia?
- Polydipsia
- Polyuria
- Blurred vision
- Weight loss
- Infections
What are two metabolic decompensation of hyperglycaemia?
Diabetic ketoacidosis and Hyperosmolar hyperglycemic state
Name some long term complications of hyperglycaemia
- Microvascular (retinopathy, neuropathy, nephropathy),
* Macrovascular (stroke, MI, PVD)
How is diabetes diagnosed?
Measuring blood glucose of HbA1c
What are the BG results diagsnotic of DM?
• Diagnostic glucose levels (venous plasma) - fasting > 7.0 mmol/l, random > 11.1 mmol/l
• OGTT 2h after 75g CHO > 11.1 mmol/l
Diagnostic HbA1c ≥ 48 mmol/mol.
What are the BG results diagnostic of intermediate hyperglycaemia?
- Impaired fasting glucose 6.1-7 mmol/l
- Impaired glucose tolerance 2h glucose ≥7.8 and <11mmol/l
- HbA1c 42-47mmol/mol
Why is it important to determine intermediate hyperglycaemia?
Identifies a group at higher risk of future diabetes and adverse outcomes such as cardiovascular disease
What is OGTT?
Oral glucose tolerance test
What is CHO?
Carbohydrate
What is the diagnostic criteria of DM?
- FBG ≥7
- 2h BG ≥ 11.1
- HbA1c ≥ 48
What is normoglycemia?
Glucose levels associated with low risk of developing diabetes or cardiovascular disease
What is it important to see if a patient fits in with the diagnostic criteria of DM?
Identify a group with significantly increased premature mortality and increased risk of microvascular and cardiovascular complications
How many samples are required for diagnostic criteria of DM?
- ONE diagnostic lab Glc plus symptoms
* TWO diagnostic lab Glc or HbA1c levels without symptoms
Why measure HbA1c to diagnose DM?
When blood glucose levels are high, glucose molecules attach to the hemoglobin in red blood cells. The longer hyperglycemia occurs in blood, the more glucose binds to hemoglobin in the red blood cells and the higher the glycated hemoglobin.
Gives indication of BG levels over last 8-12 weeks
When can HbA1c not be used for diagnosis?
- Children and young people
- Pregnancy (or recently < 2 months)
- Short duration of DM symptoms
- Acutely ill
- On meds cause rapid Glc rise (corticosteroids, antipsychotic drugs)
- Acute pancreatic damage or surgery
- Renal failure
- HIV
What is the effect of insulin on different types of tissue?
- Adipose tissue -> reduced lipolysis
- Liver -> reduced glucose production
- Muscle -> increased glucose uptake
What is the aetiology of Type 1 DM?
- Positive autoantibodies i.e. anti-GAD
* FH of Type 1
What is required for Type 1 DM to develop?
Genetic pre-disposition, plus:
• Trigger i.e. viral infection, change in environment or immune system response to environment
• Auto immunity (destruction of Islet and thus B cells)
How is the incidence of Type 1 diabetes changing?
Although proportion of diabetic population with IDDM is decreasing, total numbers of IDDM increasing.
What are the effects in different tissue types of decrease in insulin
- Adipose tissue -> increase lipolysis
- Liver -> raised Glc production
- Muscle -> reduced Glc uptake
- Hyperglycaemia, ketoaemia -> diabetic ketoacidosis
What are the symptoms of IDDM?
Short duration of: • Thirst • Tiredness • Polyuria / nocturia • Weight loss • Blurred vision • Abdominal pain
What are the signs of IDDM?
- Ketones on breath
- Dehydration
- May have increased respiratory rate, tachycardia, hypotension
- Low grade infections, thrush / balanitis
Describe the evolution of Type 2 DM
Blood glucose levels increase as β-cell function declines.
As the β-cells become damaged by lipotoxicity and glucotoxicity as a result of insulin resistance, they can eventually no longer compensate, resulting in hyperglycaemia.
Type 2 diabetes is therefore a result of underlying insulin resistance and subsequent β-cell dysfunction.
