diabetes mellitus Flashcards
If someone has low blood sugar, how is normal blood glucose achieved?
Pancreatic alpha cells synthesise and secrete glucagon
This stimulates the liver to break down glycogen and release glucose into the blood
If someone has high blood sugar, how is normal blood glucose achieved?
Pancreatic beta cells synthesise and secrete insulin
This stimulates muscles and fat cells to take glucose from the blood
What is diabetes mellitus?
Metabolic disorder of carb metabolism characterised by hyperglycaemia
High morbidity and mortality
What are blood glucose levels like?
FASTING-
Normal- 3-5mmol/l
Diabetic- 4-7mmol/l
AFTER A MEAL-
Normal- <10mmol/l, 90 mins post food
Diabetic- >20mmol/l =hyperglycaemia
What are symptoms of diabetes?
Blurry vision Excessive thirst and urination Tiredness, feeling unwell Recurring skin, gum, bladder problems Dry, itchy skin Unexpected weight loss Slow healing cuts/bruises Loss of feeling or tingly feet
What are complications of diabetes?
MACROVASCULAR
-stroke, heart disease (clotting, inflammation etc), peripheral vascular disease
MICROVASCULAR
-retinopathy (macular edema, haemorrhage etc), nephropathy (damaged glomeruli, hyperfiltration etc), peripheral neuropathy (nerve damage, necrosis etc), foot problems
What are the types of diabetes mellitus?
Type I (insulin dependent)
Type II
Gestational diabetes
Pre-diabetes- impaired glucose tolerance and impaired fasting glycaemia
What is type I diabetes?
Chronic disease, generally childhood Can be associated w thyroid disease Genetic susceptibility Linked to viral infection (eg congenital rubella syndrome) Lack of insulin production Thought to be autoimmune mediated disorder Affects islets of Langerhans Beta cells killed by antibodies
What is Type II diabetes?
Genetic predisposition ~defect in primary beta cells ~poor insulin secretion Environmental ~obesity ~periphery insulin resistance
What are the symptoms of Type II diabetes?
- Polyuria (osmotic diuresis—> frequent urination)
- Polydisia (polyuria—> more thirst and fluid intake)
- Polyphagia (increased appetite)
Also dry mouth, itchiness, more thrush, cramps, skin infections
What is gestational diabetes?
Occurs 2-5% of all pregnancies
Onset in late 2nd trimester
Predisposition- age- (usually >35), obesity, ethnicity
No obvious symptoms but can show classic diabetes symptoms
Hormonal changes—> cells less responsive to insulin
So increased resistance to insulin and high blood sugar
Long term- larger babies, mum at risk of Type II
What is pre-diabetes?
Precursor associated w obesity
High fasting blood glucose but not enough symptoms to diagnose
Lifestyle changes can reduce (50%) risk of diabetes
IFG and IGT
What is impaired glucose tolerance?
High blood sugar after eating
25-75% progress to diabetes in 10 yrs
Increased risk of cardiovascular problems
How is glucose tested?
Fasting plasma glucose ~not eaten for 8hr (detects D and preD) Oral glucose tolerance test ~not eaten for 8hr and 2hr after glucose drink (detects D and preD) Random plasma glucose test ~irrespective of eaten or not (D only) Over a period of weeks-months- ~glycated haemoglobin A1c ~fructosamine
What is glycated haemoglobin A1c?
Measures glucose associated w haemoglobin
RBC- life span is up to 3mnths
Hb1Ac indicates average glucose lvl during this period
Normal- 3.5-5.5%
Diabetic- ~6.5%
Can’t do if sickle cell anaemia, blood loss, haemolytic anaemia
Over-the-counter tests