what is diabetes mellitus

Question 1

what is diabetes mellitus defined as?

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

what clinical questions do you need to be aware of with a diabetic patient?

Answer 2

Does the person have diabetes?
Do they have hyperglycaemia? i.e. what are their blood glucose levels

What type of diabetes do they have?
I.e. What is the underlying cause of their diabetes?
( this will help determine what treatment is needed)

Question 3

how do levels of glucose change throughout the day?

Answer 3

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].

Question 4

how is blood glucose controlled?

Answer 4

Question 5

what is the key role of insulin in cellular metabolism?

Answer 5

Insulin binds to receptors on cell surfaces and controls a range of intracellular processes

Question 6

what effect does insulin have on adipose tissue?

Answer 6

reduced lipolysis

Question 7

what effect does insulin have on the liver?

Answer 7

Reduced glucose production

Question 8

what effect does insulin have on the muscle?

Answer 8

increased glucose uptake

Question 9

what are symptoms of hyperglycaemia?

Answer 9

polydipsia, polyuria, blurred vision, weight loss, infections

Question 10

what does metabolic decompensation of hyperglycemia result in?

Answer 10

DKA/HHS

Question 11

what are long term conditions of hyperglycemia?

Answer 11

microvascular (retinopathy, neuropathy, nephropathy),
macrovascular (stroke, MI, PVD)

Question 12

what are diagnostic levels for diagnosing diabetes?

Answer 12

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.

ONE diagnostic lab glucose or HbA1c plus symptoms

TWO diagnostic lab glucose or HbA1c levels without symptoms.

Question 13

is the criteria the same for diabetes and gestational diabetes?

Answer 13

no different criteria

Question 14

what is the criteria for intermediate hyperglycaemia?

Answer 14

Impaired fasting glucose 6.1-7 mmol/l

Impaired glucose tolerance 2h glucose ≥7.8 and <11mmol/l

HbA1c 42-47mmol/mol

Question 15

what is normoglycaemia?

Answer 15

used for glucose levels associated with low risk of developing diabetes or cardiovascular disease

Question 16

what is HbA1c?

Answer 16

Glycated haemoglobin
Gives indication of blood glucose levels over last 8-12 weeks

Question 17

when can HbA1c not be used for diagnosis?

Answer 17

all children and young people

pregnancy - current or recent

short duration of diabetes symptoms

patientd st high risk of diabetes who are acutely ill

a value <48mmol/mol does not exclude diabetes

patients taking medication that may cause rapid glucose rise (corticosteroids/antipsycotic drugs)

acute pancreatic damage or pancreatic surgery

renal failure

human immunodeficiency virus (HIV)

Question 18

what are key points in the history for diabetes?

Answer 18

Age at diagnosis
Any hyperglycaemic symptoms at diagnosis?
Family history of diabetes?
Personal or family history of autoimmune conditions?

Question 19

what are key examinations and initial assessment for a patient with diabetes?

Answer 19

BMI at diagnosis
Ketones
Any signs of complications
Foot examination
Retinal screening

Question 20

what are the characteristics of type 1 diabetes?

Answer 20

insulin deficiency

increased lipolysis (adipose tissue)

raised glucose production (liver)

reduced glucose uptake (muscle)

Question 21

what can hyperglycaemia and ketonaemia lead to?

Answer 21

diabetic ketoacidosis

Question 22

describe the pathway for insulin deficiency?

Answer 22

Question 23

what are the genetics of type one diabetes?

Answer 23

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

Question 24

what does the development of type 1 diabetes mellitus require?

Answer 24

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

Question 25

what is the clinical presentation of type 1 diabetes mellitus?

Answer 25

Thirst Tiredness Polyuria / nocturia Weight loss Blurred vision Abdominal pain

Question 26

on examination what might a patient with type one diabetes present with?

Answer 26

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

Question 27

what point may help clinical diagnosis of type 1 diabetes?

Answer 27

Younger age at diagnosis May be slim (need to consider weight distribution of general population) Short duration of hyperglycaemic symptoms; thirst, polyuria, blurred vision, weight loss, infections e.g thrush Other autoimmune conditions e.g thyroid Family history of other autoimmune conditions eg thyroid, pernicious anaemia, vitiligo ( beware if strong family history of diabetes) Elevated ketones

Question 28

what tests that can be done at a later date to confirm clinical diagnosis of type 1?

Answer 28

Auto antibodies GAD, IA2, ZNT8; usually take 6 weeks to come back so would not wait for this to make a diagnosis C-peptide: Usually only reliable 3y after diagnosis, would expect undetectable c-peptide in someone with longstanding t1D, low levels in more recently diagnosed. High C peptide levels would suggest person does not have t1d Genetics t1 genetic risk score- not used routinely, can be helpful if diagnosis not clear

Question 29

what effect does type 2 diabetes have on insulin?

Answer 29

Question 30

how has type 2 diabetes evolutionised?

Answer 30

Question 31

describe the incidence of both type one and two diabetes in relation to age?

Answer 31

Question 32

describe the genetics of type two diabetes?

Answer 32

Question 33

what are the symptoms of type two diabetes?

Answer 33

may have no symptoms thirst tiredeness polyuria weight loss blurred vision symptoms of complications (CVD)

Question 34

what are the signs of type 2 diabetes?

Answer 34

not ketotic overweight low grade infections (thrush, balanitis) microvascular or macrovascular complications

Question 35

how is a diagnosis of type 2 diabetes made?

Answer 35

Older age at diagnosis Overweight Family history of t2D May have no symptoms No ketones

Question 36

what are risk factors for type 2 diabetes?

Answer 36

* 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 37

Monogenic diabetes also called MODY: Maturity Onset Diabetes in the Young

Answer 37

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

Question 38

Glucokinase and Transcription factor diabetes

Answer 38

Question 39

Diagnosing diabetes- measure blood glucose or HbA1c

Answer 39

ONE diagnostic lab glucose plus symptoms TWO diagnostic lab glucose or HbA1c levels without symptoms. Diagnostic glucose levels (venous plasma) fasting ≥ 7.0 mmol/l, random ≥ 11.1 mmol/l OGTT BG ≥ 11.1 mmol/l 2h after 75g CHO Diagnostic HbA1c ≥ 48 mmol/mol.

Question 40

summarise the different types of diabetes?

Answer 40