What is Diabetes Mellitus? Flashcards
Diabetes Mellitus
“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 the symptoms of hyperglycaemia?
- Polydipsia
- Polyuria
- Blurred vision
- Weight loss
- Infections
What are the possible long term complications of hyperglycaemia?
Microvascular
- Retinopathy
- neuropathy
- Nephropathy
Macrovascular
- Stroke
- MI
- PVD
What metabolic decompensation can occur with hyperglycaemia?
DKA
HHS
How is diabetes diagnosed?
- 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 is considered intermediate hyperglycaemia?
- Impaired fasting glucose 6.1-7 mmol/l
- Impaired glucose tolerance 2h glucose ≥7.8 and <11mmol/l
- HbA1c 42-47mmol/mol
What do diabetes diagnostic criteria identify?
A group with significantly increased premature mortality and increased risk of microvascular and cardiovascular complications
What does intermediate hyperglycaemia identify?
Identifies a group at higher risk of future diabetes and adverse outcomes such as cardiovascular disease
Normoglycaemia
Glucose levels associated with low risk of developing diabetes or cardiovascular disease
What is required for a definitive diagnosis of diabetes?
- ONE diagnostic lab glucose plus symptoms
- TWO diagnostic lab glucose or HbA1c levels without symptoms.
What is HbA1c?
Glycated haemoglobin
What does HbA1c give an indication of?
Blood glucose levels over last 8-12 weeks
When can HbA1c not be used for diagnosis?
-Children and young people.
-Pregnancy—current or recent (< 2 months).
-Short duration of diabetes symptoms.
-Patients at high risk of diabetes who are acutely ill
(HbA1c ‡ 48 mmol⁄ mol confirms pre-existing diabetes, but a value < 48 mmol ⁄ mol does not exclude it and such patients must be retested once the acute episode has resolved).
-Patients taking medication that may cause rapid glucose rise; for example, corticosteroids, antipsychotic drugs (2 months or less).
-Acute pancreatic damage or pancreatic surgery.
-Renal failure.
-HIV
How can diabetes be classified?
- T1DM
- T2DM
- Other types
What is normal metabolism?
Levels of glucose and other nutrients entering the blood vary markedly during the day but, between a complete carbohydrate blow-out and NO food ingested, [BG] is maintained over a fairly tight range
What dominates the absorptive state?
Insulin
What is the only hormone which lowers [BG]?
Insulin
What role do a-cells play in [BG] control?
- a-cells secret glucagon
- Stimulation of the liver (glycogenolysis and gluconeogenesis)
What role do B-cells play in the[BG] control?
- B-cells secrete insulin
- Insulin involved in glucose uptake in adipose, liver and skeletal muscle
What are the genetic linked risks of developing T1DM?
- Monozygotic twins 30-50% concordance
- If father has Type 1: 6% risk
- If mother has Type 1: 1% risk
- If sibling has Type 1: 8% risk
- If non-identical twin has Type 1: 10% risk
- If both parents have Type 1: 30% risk
What does development of T1DM require?
Genetic pre-disposition plus
- Trigger e.g.? Viral infection
- Auto immunity
What effect does insulin have on adipose tissue?
Reduced lipolysis
What effect does insulin have on the liver?
Reduced glucose production
What effect does insulin have on muscle?
Increased glucose uptake
