Diabetes and hypoglycaemia Flashcards
What is glucose?
Glucose is a major energy substrate
What is blood glucose levels maintained through?
○ Maintenance of blood glucose levels through (4-6mmol):
○ Dietary carbs eaten and then absorbed
○ Glycogenolysis in liver
○ Gluconeogenesis
What is the role of the liver after a meal?
stores glucose as glycogen
What is the role of the liver during a fast?
makes glucose available through glycogenolysis and gluconeogenesis
Why is it important to regulate glucose?
○ Brain and erythrocytes require continuous supply: – therefore avoid deficiency
○ Brain and RBCs cannot metabolise glucose themselves
○ High glucose and metabolites cause pathological changes to tissues;
What is diabetes mellitus?
Metabolic disorder characterised by chronic hyperglycaemia, glycosuria and associated abnormalities of lipid and protein metabolism
What is hyperglycemia a result of?
Hyperglycaemia result of increased hepatic glucose production and decreased cellular glucose uptake
What is glycosuria and at what level does it occur?
Glucose in urine
Blood glucose > ~ 10mmol/L
What is involved in the diagnosis of diabetes mellitus?
○ In the presence of symptoms: (polyuria, polydipsia & weight loss for Type I)
○ Random plasma glucose ≥ 11.1mmol/l (200 mg/dl)
▪ Random is defined as any time of day without regard to time since last meal OR
• Fasting plasma glucose ≥ 7.0 mmol/l (126 mg/dl) Fasting is defined as no caloric intake for at least 8h
OR
• Oral glucose tolerance test (OGTT): plasma glu ≥ 11.1 mmol/l
○ In the absence of symptoms:
-test blood samples on 2 separate days
What are the value range of patients with impaired glucose tolerance(IGT) of:
- Fasting plasma glucose
- OGTT value
○ Fasting plasma glucose 6.1-6.9mmol/L
○ OGTT value of 7.8 – 11.1 mmol
What are the value range of patients with impaired fasting glycaemia(IFG) of:
- Fasting plasma glucose
- OGTT value
○ Fasting plasma glucose ‹ 7.0 mmol/L and
○ OGTT value of < 7.8
What individuals is OGTT used . in and to determine what?
OGTT used in individuals with fasting plasma glucose of ‹ 7.0 mmol/L to determine glucose tolerance status.
In what patients should oral glucose tolerance test(OGTT) be carried out in?
○ In patients with IFG
○ In unexplained glycosuria
○ In clinical features of diabetes with normal plasma glucose values
○ For the diagnosis of acromegaly (excess GH results in excess glucose)
Steps involved in OGTT
- Check blood glucose first
- 75g oral glucose and test after 2 hour
- Blood samples collected at 0 and 120 mins after glucose
- Subjects tested fasting after 3 days of normal diet containing at least 250g carbohydrate
- If blood glucose >8.1 = diabetes
What is type 1 diabetes?
Insulin secretion is deficient due to autoimmune destruction of b-cells in pancreas by T-cells
What is type 2 diabetes?
- Insulin secretion is retained but there is target organ resistance to its actions
- Insensitivity of receptors
What is secondary diabetes caused by?
• Chronic pancreatitis, pancreatic surgery, secretion of antagonists
What does gestational diabetes occur due to and when?
- Occurs for first time in pregnancy due to placental hormones i.e. HPL
- Happens between 18-24 weeks
What are all the classifications of diabetes?
- Type 1
- Type 2
- Secondary
- Gestational
Who is type 1 DM predominantly in?
○ Predominantly in children and young adults; but other ages as well
What is the onset of type 1 DM?
Sudden onset
What is the most common cause of type 1 DM?
Most common cause is autoimmune destruction of B-cells
What strong genetic link is there for type 1 DM?
○ Strong link with HLA genes within the MHC region on chromosome 6
Pathogenesis of type 1 DM?
○ HLA class II cell surface presents as foreign and self-antigens to T-lymphocytes to initiate autoimmune response
○ Circulating autoantibodies to various cell antigens against:
○ Glutamic acid decarboxylase
○ Tyrosine-phosphatase-like molecule
○ Islet auto-antigen
○ The most commonly detected antibody associated with type 1 DM is the islet cell antibody
