What is Diabetes Mellitus? (including Epidemiology of Diabetes)

Question 1

what is diabetes mellitus?

Answer 1

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

Question 2

symptoms of hyperglycaemia?

Answer 2

polydipsia, polyuria, blurred vision, weight loss, infections

Question 3

what are the long term complications of hyperglycaemia?

Answer 3

microvascular (retinopathy, neuropathy, nephropathy),

macrovascular (stroke, MI, PVD)

Question 4

what is the number for diagnosing diabetes with blood glucose level?

Answer 4

fasting 7.0 mmol/l, random  11.1 mmol/l

Question 5

what is the number for diagnosing diabetes with HbA1c?

Answer 5

≥ 48 mmol/mol.

Question 6

what group of people is intermediate hyperglycaemia a risk?

Answer 6

identifies a group at higher risk of future diabetes and adverse outcomes such as cardiovascular disease

Question 7

when can HbA1c not be used for diagnosis?

Answer 7

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.

Question 8

aetiology of type 1 diabetes?

Answer 8

positive auto antibodies

Question 9

what are the genetics of type 1 diabetes?

Answer 9

Background population risk ~0.4%
If mother has Type 1: 	1% risk
If father has Type 1: 	6% 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
Monozygotic twins 30-50% concordance

Question 10

what does the development of type 1 diabetes mellitus require?

Answer 10

Genetic pre-disposition plus
Trigger e.g.? Viral infection
Auto immunity

Question 11

symptoms of type 1 diabetes mellitus?

Answer 11

Short duration of
Thirst
Tiredness
Polyuria / nocturia
Weight loss 
Blurred vision
Abdominal pain

Question 12

signs of type 1 DM?

Answer 12

Ketones on breath
Dehydration
May have increased respiratory rate, tachycardia, hypotension.
Low grade infections, thrush / balanitis

Question 13

genetics of type 2 diabetes?

Answer 13

Identical twin 		90-100% risk
One parent 		15% 
Both parents 	 	75% 
Sibling 	 		10%
Non-identical twin 	10%

Question 14

symptoms of type 2 diabetes?

Answer 14

May have no symptoms
Thirst
Tiredness
Polyuria / nocturia
Sometimes weight loss
Blurred vision
Symptoms of complications e.g. CVD

Question 15

signs of type 2 diabetes?

Answer 15

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

Question 16

risk factors for diabetes?

Answer 16

Overweight
• Family history
• Over age 30 years if Maori ⁄ Asian (Indian subcontinent)
⁄ Pacific Island descent
• Over age 40 years if European
• Previous history of diabetes in pregnancy (Gestational Diabetes)
Had a big baby (more than 4 kg)—not in immediate post-natal period
• Inactive lifestyle, lack of exercise
• Previous high blood glucose ⁄ impaired glucose tolerance

Question 17

what are the other types of diabetes?

Answer 17

Recognised genetic syndromes : MODY

Gestational diabetes

Secondary diabetes

Question 18

what is maturity onset diabetes in the young?

Answer 18

Autosomal dominant
? 5% of people with diabetes
Impaired beta-cell function
Single gene defect

Question 19

what are characteristics of glucokinase mutation diabetes?

Answer 19

Onset at birth
Stable hyperglycaemia
Diet treatment
Complications rare

Question 20

what are characteristics of transcription factor mutation diabetes?

Answer 20

Adolescence/young adult onset
Progressive hyperglycaemia
1/3 diet, 1/3 OHA, 1/3 Insulin
Complications frequent

Question 21

what is secondary diabetes mellitus?

Answer 21

Drug therapy e.g corticosteroids
Pancreatic destruction
Haemochromatosis- excess iron deposition
Cystic fibrosis 
Chronic pancreatitis
pacreatectomy
Recognised genetic syndromes-DIDMOAD
Rare endocrine disorders e.g. Cushings syndrome, Acromegaly, Pheochromocytoma

Question 22

what happens to hyperglycaemia in pregnancy?

Answer 22

Increasing insulin resistance in pregnancy
Associated with FH of Type 2 diabetes
Increased risk of Type 2 diabetes later in life
Develops 2nd / 3rd trimester
More common if overweight and inactive
Neonatal problems:
macrosomia / respiratory distress / neonatal hypoglycaemia