What is Diabetes Mellitus? + Epidemiology

Question 1

Where do we get glucose from?

Answer 1

Oral intake - glucose absorbed from the gut

Liver - gluconeogenesis and glycogen breakdown

Question 2

Define diabetes mellitus

Answer 2

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/action/both

Question 3

Symptoms of hyperglycaemia

Answer 3

polydipsia (drinking a lot)

polyuria

blurred vision

weight loss

infections

Question 4

Long term complications of hyperglycaemia?

Answer 4

microvascular - retinopathy, neuropathy, nephropathy (kidney)

Macrovascular - stroke, MI, PVD - limb aputation

Question 5

What is the criteria required to diagnose diabetes?

Answer 5

If symptomatic you need 1 positive diagnostic blood test

If asymptomatic you need 2 diagnostic blood tests or HbA1c levels

Question 6

What is intermediate hyperglycaemia?

Answer 6

Patient that shows impaired fasting glucose, impaired glucose tolerance and a high HbA1c
but lower than the diagnostic cut-off for diabetes.

Identifies a group at higher risk of future diabetes and adverse outcomes such as CVD

Question 7

What is the HbA1c test? Explain how it works?

Answer 7

A blood test used to monitor how well or poorly a patient’s diabetes is being controlled

Glucose in the blood binds irreversibly to a specific part of haemoglobin in RBC’s, forming HbA1c

The higher the glucose, the higher the HbA1c

Question 8

How long does HbA1c circulate?

Answer 8

For the lifespan of the RBC

so the HbA1c blood test reflects the prevailing blood glucose levels over the preceding 2-3 months

Question 9

When can HbA1c not be used for diagnosis?

Answer 9

All children and young people - rapidly changing condition

Pregnancy—current or recent (< 2 months)

Short duration of diabetes
symptoms

Patients at high risk of diabetes who are acutely ill

Acute pancreatic damage or pancreatic surgery

Renal failure

Human immunodeficiency
virus (HIV) infection

Question 10

Genetics of type 1 diabetes: Risk %

Answer 10

If father has Type 1: 6%
If mother has Type 1: 1%

If both parents have type 1: 30%

Question 11

True or false: if person has type 1 they are more likely to have other autoimmune conditions too such as Coeliac and thyroid disease

Answer 11

true

Question 12

Why might a person have high [BG]plasma but not have diabetes?

Answer 12

stress - stress causes the release of counter-regulatory hormones so levels of glucagon, cortisol, GH and Catecholamines all increase

Question 13

Clinical presentation of type 1 DM

Answer 13

Often short duration of:
Thirst
Tiredness
Polyuria/nocturia
Weight loss
Blurred vision
Abdominal pain

On exam:
Ketones on breath (unique to type 1 due to lack of insulin)

dehydration

increased resp rate, hypotension

low grade infections, thrush

Question 14

Characteristics of type 2 DM

Answer 14

Much more latent process - presents over slower time course (years)

Insulin resistance goes up first + glucose increases

Often asymptomatic but if have them - thirst, tiredness, polyuria/nocturia, sometimes weight loss, blurred vision

not ketotic

usually overweight

In type 2 DM may have micro vascular or macrovascular complications at Dx

Question 15

Genetics of type 2 DM: Risk %

Answer 15

Identical twin: 90-100%

One parent: 15%

Both parents: 75%

Sibling: 10%

Question 16

MODY - Maturity Onset Diabetes in the Young

Answer 16

Autosomal dominant

single gene defect

if child has strong FH then should look for this

Important as some of the treatments for MODY are different to type 1

Question 17

What are the 2 most common mutations in MODY

Answer 17

Glucokinase mutations

Transcription factor mutations

Question 18

Describe Glucokinase mutations

Answer 18

Onset at birth

Stable hyperglycaemia

Diet treatment

Complications rare

Question 19

Describe Transcription factor mutations

Answer 19

Adolescence/young adult onset

Progressive hyperglycaemia

Treatment = diet

Oral Hypoglycaemic Agent and Insulin

Complications frequent

Question 20

What is gestational diabetes

Answer 20

A mother getting diabetes during pregnancy without having it previously - develops 2nd / 3rd trimester

Increasing insulin resistance in pregnancy

Associated with FH of Type 2 diabetes

Increased risk of Type 2 diabetes later in life - women are having children later nowadays

More common if overweight and inactive

Like a warning sign - likely to develop type 2 diabetes within 10 years

Question 21

How can gestational diabetes affect the neonate?

Answer 21

macrosomia (larger newborn)

respiratory distress

neonatal hypoglycaemia

Question 22

What is secondary diabetes?

Answer 22

Diabetes that occurs due to another condition

Common Causes:

Any major disease of the exocrine pancreas can be associated with development of diabetes (CF, chronic pancreatitis, haemochromatosis)

Endocrinopathies

Drug or chemical induced diabetes (steroids)

Question 23

What is Phaeochromocytoma

Answer 23

too much noradrenaline in your system

Question 24

Case:

27 year old business man
Goes to GP because thirst, polyuria and nocturia
Lost 1 stone in last month
Tired and lethargic – less energy for his usual activities- judo, football
Random glucose 19 mmol/l
BMI 22 (normal range)

Blood Ketones 1.6 (urine ketones +++)

Family history of thyroid problems and type 1 diabetes

What is the differential diagnosis

Answer 24

Has diabetes – type 1 due to short duration of symptoms and normal BMI

FH, Ketone level increased (norm = 0.6 or less), thirst

Question 25

Diagnostic tests for diabetes

Answer 25

measure blood glucose of HbA1c

Oral glucose tolerance test

Blood glucose monitoring