What is Diabetes Mellitus? (including Epidemiology of Diabetes) Flashcards
How does the body make/get glucose?
Oral intake - Glucose absorbed from the gut
Hepatic - Gluconeogenesis and Glycogen breakdown
what uses glucose in the body?
brain
muscle
adipose tissue
A continuous supply of glucose is essential for what?
the brain
Levels of glucose and other nutrients entering the blood ____ _________ during the day
But, between a complete carbohydrate blow-out and NO food ingested, blood glucose concentrations are ____________ ____ _ _____ _____
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, blood glucose concentrations are maintained over a fairly tight range
Insulin dominates the _________ state; it is the only hormone which ______ blood glucose levels
Insulin dominates the absorptive state; it is the only hormone which lowers blood glucose levels
study this image carefully and think about it
affect of insulin on A
Reduced lipolysis
affect of insulin on B
Reduced glucose production
affect of insulin on C?
Increased glucose uptake
what is the definition of diabetes?
“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”
what symptoms does hyperglycaemia cause?
polydipsia - excessive thirst or excess drinking
polyuria - excessive or an abnormally large production or passage of urine
blurred vision - Eye balls change shape leading to blurred vision
weight loss
infections
what does metabolic decompensation caused by hyperglycaemia cause?
DKA/HHS
(Hyperosmolar Hyperglycaemic State)
what are long term complications of hyperglycaemia?
microvascular (retinopathy, neuropathy, nephropathy)
macrovascular (stroke, MI, PVD)
(Retinopathy is any damage to the retina of the eyes, which may cause vision impairment)
(neuropathy refers to the conditions that result when nerves that carry messages to and from the brain and spinal cord from and to the rest of the body are damaged or diseased)
(Nephropathy is a general term for the deterioration of proper functioning in the kidneys)
name A?
All values are for venous plasma samples and units are mmol/L
name B
All values are for venous plasma samples and units are mmol/L
name C?
All values are for venous plasma samples and units are mmol/L
How can HbA1c levels diagnose diabetes?
Diagnostic HbA1c ≥ 48 mmol/mol
what is intermediate hyperglycaemia?
Increased risk of diabetes but don’t yet have it
Close eye of them, may get a yearly check up
a state of raised glycaemic levels in a person without diabetes
It is an independent risk-factor for type 2 diabetes and cardiovascular disease
The primary aim of management of intermediate hyperglycaemia is to prevent progression to diabetes
How do you diagnose diabetes
measure blood glucose or HbA1c
ONE diagnostic lab glucose plus symptoms
TWO diagnostic lab glucose or HbA1c levels without symptoms
What levels are rquired for someone to have intermediate hyperglycaemia?
Impaired fasting glucose 6.1-7 mmol/l
Impaired glucose tolerance 2h glucose ≥7.8 and <11mmol/l
HbA1c 42-47mmol/mol
why the criteria for diabetes?
Diabetes diagnostic criteria identify a group with significantly increased premature mortality and increased risk of microvascular and cardiovascular complications
What is normoglycaemia?
‘normoglycaemia’ is used for glucose levels associated with low risk of developing diabetes or cardiovascular disease
What is intermediate hyperglycaemia?
Intermediate hyperglycaemia (IGT and IFG) identifies a group at higher risk of future diabetes and adverse outcomes such as cardiovascular disease
What does diabetes diagnostic criteria say about a person?
Diabetes diagnostic criteria identify a group with significantly increased premature mortality and increased risk of microvascular and cardiovascular complications
how can HbA1c be used in diagnosing diabetes?
Glucose in the blood binds irreversibly to a specific part of haemoglobin in red blood cells, forming HbA1c
The higher the glucose, the higher the HbA1c
HbA1c circulates for the lifespan of the red blood cell, so reflects the prevailing blood glucose levels over the preceding 2-3 months
American Diabetes Association have recommended that HBA1c can be used to diagnose diabetes (HbA1c >/= 48)
what are the advantages of using glucose as a diagnostic tool?
established method
smaller variation between labratories
more feasible in developing countries
directly measures molecule thought to cause diabetic complications
what are the disadvantages of using glucose as a diagnostic tool?
requies a fasting state
may require OGTT
higher variability within individuals
what are the advantages of using HbA1c as a diagnostic tool?
No need for a fasting sample
More stable after collection
Marker of glycaemic control
Lower variability within individuals
what are the disadvantages of using HbA1c as a diagnostic tool?
Measurement can be misleading with haemoglobinopathies, anaemia or renal failure
May differ with age & ethnicity
More costly
Surrogate marker of hyperglycaemia
When can HbA1c not be used for 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
what are the types of diabetes?
Maturity Onset Diabetes of the Young (MODY) is an inherited form of diabetes mellitus
what is the most common type of diabetes?
is diabete sincreasing or decreasing around the world?
increasing
is the numbers of diabetes increasing in scotland?
yes
5.5% of the population now have it
what is the cause of type 1 diabetes?
Many different antibodies you can use to look for
Looking for antibodies that are attacking part of the pancreas attacking B cells leading to a lack of insulin
Anti GAD main ones
what is the genetic risk of type 1 diabetes?
if father has type 1 = 6% risk
if mother has type 1 = 1% risk
if both parents have type 1 = 30% risk
if sibling has type 1 = 8% risk
Monozygotic twins = 30-50% concordance
If non-identical twin has Type 1 = 10% risk
Development of Type 1 Diabetes Mellitus requires what?
Genetic pre-disposition plus:
Trigger e.g.? Viral infection
Auto immunity
People can be diagnosed at all different ages and it is unknown why people develop it at certain points
Struggled to find the underlying thing that starts the process
Patient with type 1 diabetes more likely to have other autoimmune conditions like coeliac disease and thyroid disease
T1DM is characterised by what?
insulin deficiency
flow chart showing type 1 diabetes summary
What is the clinical presentation of type 1 diabetes mellitus on the short term?
- Thirst
- Tiredness
- Polyuria/nocturia
- Weight loss
- Blurred vision
- Abdominal pain
Key message – essential to make this diagnosis. Don’t ignore these symptoms at any age
What is the clinical presentation of type 1 diabetes mellitus on examination?
- Ketones on breath
- Dehydration
- May have increased respiratory rate, tachycardia, hypotension
- Low grade infections, thrush/balanitis
how did the survival time of T1DM change after the discovery of insulin
it greatly increased
describe the evolution of type 2 diabetes
Pancreas becomes tired trying to overcome the increasing insulin resistance then glucose levels rise
what is the genetics of type 2 diabetes?
- Identical twin = 90-100% risk
- One parent = 15% risk
- Both parents = 75% risk
- Sibling = 10% risk
- Non-identical twin = 10% risk
study this image as previously seen
Insulin has a key role in cellular metabolism
A
altered lipolysis
B
increased glucose production
C
reduced glucose uptake
Body not bale to produce enough insulin to keep up =
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 e.g. 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
Screening for diabetes in asymptomatic populations:
Who would you encourage to have a risk assessment?
All eligible adults aged 40 and above, 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 the risk of type 2 diabetes
What are particular conditions can increase the risk of type 2 diabetes?
cardiovascular disease
hypertension
obesity
stroke
polycystic ovary syndrome
a history of gestational diabetes
mental health problems
what are other types of diabetes?
- Recognised genetic syndromes: MODY - genetic cause of diabetes
- Gestational diabetes - occurring in pregnancy
- Secondary diabetes - occurring due to pancreatic insult
Describe the features of MODY: Maturity Onset Diabetes in the Young
- Autosomal dominant
- ? 5% of people with diabetes
- Impaired beta-cell function
- Single gene defect
what is important in people with new onset diabetes?
take a history
what are the 2 ways MODY is caused?
Glucokinase mutations:
- Onset at birth
- Stable hyperglycaemia
- Diet treatment
- Complications rare
Transcription factor mutations (HNF-1a, HNF-1b, HNF-4a):
- Adolescence/young adult onset
- Progressive hyperglycaemia
- 1/3 diet, 1/3 OHA, 1/3 Insulin
- Complications frequent
What is Gestational diabetes - hyperglycaemia of pregnancy?
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
what is secondary diabetes?
Any major disease of the exocrine pancreas can be associated with development of diabetes e.g. Chronic pancreatitis, Haemochromatosis, Cystic fibrosis
Endocrinopathies e.g. Acromegaly, Cushing’s syndrome, Glucagonoma, Phaeochromocytoma
Drug or chemical induced diabetes e.g. steroids
