Diabetes Mellitus Including Epidaemiology Flashcards
What are symptoms of hyperglycaemia?
Polydipsia
Polyuria
Blurred vision
Infections
DKA and HHS
Hyperosmolar hyperglycemic state is a metabolic complication of diabetes mellitus (DM) characterized by severe hyperglycemia, extreme dehydration,hyperosmolar plasma, and altered consciousness. It most often occurs in type 2 DM, often in the setting of physiologic stress.
What are the long term complications of hyperglycaemia?
Microvascular - retinopathy, neuropathy, nephropathy
Macrovascular - stroke, MI and PVD
What are the diagnostic tests for diabetes?
- Diagnostic glucose levels (venous plasma) fasting greater than or equal to 7.0 mmol/l, random greater than or equal to 11.1 mmol/l
- OGTT 2h after 75g CHO greater than or equal to 11.1 mmol/l
- Diagnostic HbA1c ≥ 48 mmol/mol.
- (different criteria for gestational diabetes)
OGTT stands for oral glucose tolerance test
CHO stands for carbohydrate
What are the values for intermediate hyperglycaemia?
Impaired fasting glucose 6.1 - 7 mmol/l
Impaired glucose tolerance 2h glucose greater than or equal to 7.8 and less than 11 mmol/l
HbA1c 42-47
How many diagnostic procedures are required for diagnosing diabetes?
One diagnostic lab glucose plus symptoms
Two diagnostic lab glucose or HbA1c levels without symptoms
What is HbA1c?
Glycated haemoglobin
Gives indication of blood glucose levels over last 8-12 weeks
Measured primarily to identify the three-month average plasma glucose concentration
When can’t HbA1c be used to make a diagnosis?
- All 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). HbA1c can be used in patients taking such medication long term (i.e. over 2 months) who are not clinically unwell.
- Acute pancreatic damage or pancreatic surgery.
- Renal failure.
- Human immunodeficiency virus (HIV) infection.
Look
Describe the deviation of blood glucose during the day
- 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.
- Insulin dominates the absorptive state. Only hormone which lowers [BG].
What age group has the highest incidence of diabetes?
10-19
Describe the genetic chance of inheritance of type 1 diabetes
What is the development of type 1 diabetes?
–Genetic pre-disposition plus
–Trigger e.g.? Viral infection
–Auto immunity
How does insulin act on adipose tissue, the liver and muscle?
Adipose tissue - reduces lipolysis
Liver - reduced glucose production
Muscle - increase glucose uptake
What is the effect of reduced insulin on the glucose production by the liver and glucose uptak by the muscles?
Also what is the effect of insulin deficiency on adipose tissue?
Liver - raised glucose production
Muscle - raised glucose uptake
Adipose tissue - increase in lipolysis - risk of DKA
What is the effect of hyperglycaemia on the kidney?
Hyperglycaemia causes glucosuria (osmotic diuresis)
This causes loss of water and electrolytes, leading to dehydration and impaired renal function
What is the clinical presentation of type 1 diabetes mellitus?
- Thirst
- Tiredness
- Polyuria / nocturia
- Weight loss
- Blurred vision
- Abdominal pain
On examination:
- Ketones on breath
- Dehydration
- May have increased respiratory rate, tachycardia, hypotension.
- Low grade infections, thrush / balanitis
What are the genetic inheritance traits of type 2 diabetes?
- Identical twin 90-100% risk
- One parent 15%
- Both parents 75%
- Sibling 10%
- Non-identical twin 10%
Why might beta cells become damaged in type 2 diabetes?
Lipotoxicity
Glucotoxicity
They can no longer compensate resulting in hyperglycaemia
What are the symptoms of type 2 diabetes?
May have no symptoms
Thirst
Tiredness
Polyuria/nocturia
Sometimes weight loss
Blurred vision
Symptoms of complications (CVD)
What are the signs of type 2 diabetes?
- Not ketotic
- Usually overweight but not always
- Low grade infections, thrush / balanitis
- In type 2 DM may have micro vascular or macrovascular complications at Dx
What are the risk factors for type 2 diabetes?
Overweight
Family history
Over 30 if Maori / Asian
Over 40 if European
Previous history of diabetes in pregnancy
Had a big baby (more than 4kg) - not in immediate post - natal period
Inactive lifestlye (lack of exercise)
Previous high blood glucose / impaired glucose tolerance
What are other types of diabetes mellitus?
Recognised genetic syndromes: MODY
Gestational diabetes
Secondary diabetes
Define MODY
Maturity Onset Diabetes in the Young
- Autosomal dominant
- ? 5% of people with diabetes
- Impaired beta-cell function
- Single gene defect
Family history very relevant
What are the potential gene defects for MODY?
Glucokinase mutations
Transcription factor mutations
How do you tell the difference between glucokinase mutations and transcription factor mutations?
Glucokinase mutations:
Onset at birth
Stable hyperglycaemia
Diet treatment
Complications rare
Transcription factor mutations:
Adolescence/young adult onset
Progressive hyperglycaemia
1/3 diet, 1/3 OHA, 1/3 Insulin
Complications frequent
OHA - oral hypoglycaemic agent
How does secondary diabetes mellitus arise?
- Drug therapy e.g corticosteroids
- Pancreatic destruction
–Haemochromatosis- excess iron deposition
–Cystic fibrosis
–Chronic pancreatitis
–pancreatectomy
- Recognised genetic syndromes-DIDMOAD
- Rare endocrine disorders e.g. Cushings syndrome, Acromegaly, Pheochromocytoma
What is gestational diabetes?
Increasing insulin resistance during pregnancy
Develops in 2nd/3rd trimester
What are the associations of gestational diabetes?
Increased risk of type 2 diabetes later in life
Associated with a family history of type 2 diabetes
What are the neonatal problems associated with diabetes?
Macrosomia
The term “fetal macrosomia” is used to describe a newborn who’s significantly larger than average
Respiratory distress
Neonatal hypoglycaemia
