Lecture 8 What is Diabetes Mellitus

Question 1

Define diabetes

Answer 1

A group of metabolic diseases of multiple causes 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 are the symptoms of hyperglycaemia

Answer 2

polydipsia, polyuria, blurred vision, weight loss, infections

Question 3

What molecular decompensation are involved in hyperglycaemia

Answer 3

DKA HHS

Question 4

What are the long term complications of hyperglycaemia

Answer 4

Retinopathy
Neuropathy
Nephropathy
Stroke
MI
PVD

Question 5

Normal fasting plasma glucose

Answer 5

=/<6

Question 6

Intermediate fasting plasma glucose

Answer 6

6.1-6.9

Question 7

DM fasting plasma glucose

Answer 7

=/>7

Question 8

Random plasma glucose that would suggest DM

Answer 8

> /=11.1

Question 9

Normal 2 hour OGTT value

Answer 9

=7.7

Question 10

Intermediate 2 hours OGTT value

Answer 10

7.8-11

Question 11

DM 2 hour OGTT value

Answer 11

> /=11.1

Question 12

Intermediate hyperglycaemia in HbA1c

Answer 12

HbA1c 42-47mmol/mol

Question 13

Advantages of testing glucose

Answer 13

Established method
Smaller variation between laboratories
More feasible in developing countries
Directly measures molecule thought to cause diabetic complications

Question 14

Disadvantages of testing glucose

Answer 14

Requires a fasting
May require OGTT
Higher variability within individuals

Question 15

Advantages of testing HbA1c

Answer 15

No need for fasting sample
More stable after collection
Marker of glyceamic control
Lower variability within individuals

Question 16

Disadvantages of testing HbA1c

Answer 16

Measurement can be misleading due to haemoglobinopathies, anaemia or renal failure
May differ with age and ethnicity
More costly
Surrogate marker of hyperglycaemia

Question 17

When HbA1c cannot be used for diagnosis

Answer 17

• All children and young people
• Pregnant or recently pregnant
• Short duration of diabetes symptoms
• Acutely ill patients
• HbA1c >48mmol/mol = pre-existing diabetes, nut value below this does not exclude it- patient must be retested once acute episode has resolved
• Taking medication that causes rapid rise in glucose- corticosteroids, antipsychotic drugs
• Acute pancreatic damage or pancreatic surgery
• Renal failure
• HIV

Question 18

What is the risk of an individual if their father has type 1 DM

Answer 18

6%

Question 19

What is the risk of an individual of their mother has type 1 DM

Answer 19

1%

Question 20

What is the risk of an individual if both parents have type 1 DM

Answer 20

30%

Question 21

What is the risk of an individual if their non-identical twin has type 1 DM

Answer 21

30%

Question 22

Aetiology of type 1 diabetes

Answer 22

• Genetic predisposition
• Trigger e.g. viral infection
• Auto immunity

Question 23

Clinical presentation of type 1 diabetes on short duration

Answer 23

• Thirst
• Tiredness
• Polyuria/nocturia
• Weight loss
• Blurred vision
• Abdominal pain

Question 24

Clinical presentation of type 1 diabetes on exmination

Answer 24

• Ketones on breath
• Dehydration
• May have increased respiratory rate, tachycardia, hypotension
• Low grade infections, thrush, balanitis (diaper rash)

Question 25

What is insulin

Answer 25

* Protein consisting of alpha(21) and beta(30) chains | * Linked together with disulphide bonds

Question 26

What is the risk of an individual for type 2 diabetes if their twin has it

Answer 26

90-100%

Question 27

What is the risk of an individual for type 2 diabetes if one parent has it

Answer 27

15%

Question 28

What is the risk of an individual for type 2 diabetes if both parents have type 2 diabetes

Answer 28

75%

Question 29

What is the risk of an individual for type 2 diabetes if their sibling has type 2 diabetes

Answer 29

10%

Question 30

What is the risk of an individual for type 2 diabetes if their non-identical twin has type 2 diabetes

Answer 30

10%

Question 31

Symptoms of type 2 diabetes

Answer 31

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

Question 32

Signs of type 2 diabetes

Answer 32

* No ketotic * Usually overweight but not always * Low grade infection, thrush/balanitis * May have microvascular complications and Dx

Question 33

Screening for Diabetes in asymptomatic patients

Answer 33

• All eligible adults aged 40 and over, except pregnant women • People aged 25-39 of south Asian, Chinese, African-Caribbean, Black African and other high risk black and minority ethnic groups except pregnant women • Adults with conditions that increase risk of type 2 diabetes  CV disease  Hypertension  Obesity  Stroke  PCOS  History of gestational diabetes  Mental health problems

Question 34

Name other types of DM

Answer 34

* MODY: Maturity Onset Diabetes in the Young * Gestational diabetes * Secondary diabetes

Question 35

What is the cause of MODY

Answer 35

 Autosomal dominant  5% of people with diabetes  Impaired beta-cell function  Single gene defect  Glucokinase mutations- onset at birth, stable hyperglycaemia, diet treatment, complications rare  Transcription factor mutations (HNF-1a, HNF=1b, HNF-4a). Adolescence/youg adult onset, progressive hyperglycaemia, 1/3 diet, 1/3 OHA, 1/3 insulin. Complications frequent

Question 36

What is gestational diabetes associated with

Answer 36

 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

Question 37

What are neonatal problems in gestational diabetes

Answer 37

macrosomia (newborn who's significantly larger than average), respiratory distress, neonatal hypoglycaemia

Question 38

Name causes of secondary diabetes

Answer 38

```  Any major disease of the exocrine pancreas – Chronic pancreatitis – Haemochromatosis – Cystic fibrosis  Endocrinopathies – Acromegaly – Cushing’s syndrome – Glucagonoma – Pheochromocytoma  Drug or chemical induced diabetes – Steroids ```