What is Diabetes Mellitus Flashcards
What is diabetes mellitus?
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 are symptoms of hyperglycaemia?
Polydipsia (excessive thirst)
Polyuria (excess production or passage of urine - greater than 2.5L or 3L over 24 hours in adults)
Blurred vision
Weight loss
Infections
What is polydipsia?
Excessive thirst
What is polyuria?
Excess production or passage of urine
What are some metabolic decompensations that hyperglycaemia leads to?
DKA - Diabetic ketoacidosis
HHS - Hyperglycemic Hyperosmolar Syndrome
What long term complications can hyperglycaemia cause?
Microvascular (retinopathy, neuropathy, nephropathy)
Macrovascular (stroke, MI, PVD)
What is measured to diagnose diabetes?
Glucose or HbA1c
Are glucose levels measured from arterial or venous plasma?
Venous plasma
What glucose levels are considered to a diabetic diagnosis?
In fasting more than or equal to 7mmol/L or random time where more than or equal to 11.1mmol/L
What does OGTT stand for?
Oral glucose tolerance test
How is the oral glucose tolerance test done?
Measure 2 hours after eating 75g CHO and glucose more than or equal to 11.1 mmol/L is diabetic
What level of glucose is considered to be diabetic after the OGTT?
More than or equal to 11.1mmol/L
What level of HbA1c is considered to be diabetic?
Over or equal to 48mmol/L
What are the diagnostic levels for fasting glucose, OGTT and HbA1c for intermediate hyperglycaemia?
Impaired fasting glucose 6.1-7mmol/L
Impaired glucose tolerance test >=7.8 and <= 11mmol/L
HbA1c 42-47mmol/L
Why is the diabetic diagnostic level criteria at the levels it is?
Identifies a group with significant increased premature mortality and increased risk of microvascular an cardiovascular complications
Why is the diagnostic criteria for intermediate hyperglycaemia at the levels it is?
Identifies a group at higher risk of future diabetes and adverse outcomes
What are the different levels of increased glucose?
‘Normoglycaemia’ (glucose levels associated with low risk of developing diabetes)
Intermediate hyperglycaemia (identifies a group with higher risk of future diabetis and adverse outcomes)
Diabetes diagnostic criteria (identifies a group with significant increase premature mortability and increased risk of adverse outcomes)
What is required to diagnose diabetes?
Measure blood glucose or HbA1c
One diagnostic lab glucose plus symptoms
Two diagnostic lab glucose or HbA1c levels without symptoms
What is HbA1c?
Glycosylated haemoglobin, gives an indication of blood glucose levels over the last 8-12 weeks
Over what time period does HbA1c give an indication of blood glucose levels?
Last 8-12 weeks
When can HbA1c not be used to diagnose diabetes?
What are the different classifications of diabetes?
Type 1 (10.9%)
Type 2 (88.2%)
Other types (0.9%)
Is type 1 or type 2 diabetes more prevalent?
Type 2
What is the only hormone that can lower [BG]?
Insulin
What cell produces insulin?
B cells
What cell produces glucagon?
a cells
What effect does insulin have on adipose tissue?
Reduces lipolysis
What is lipolysis?
Lipid triglycerides are hydrolysed into a glycerol and three fatty acids, breaks down fat into energy
What effect does insulin have on the liver?
Reduces glucose production
What effect does insulin have on muscle?
Increased glucose uptake
Is the incidence of type 1 diabetes greater in younger or older people?
Younger people
What is the background population risk of developing type 1 diabetes?
0.4%
What is the percentage risk of developing type 1 diabetes if your: mother, father, sibling, non-identical twin, both parents, monozygotic twin has it?
Mother - 1%
Father - 6%
Sibling - 8%
Non-identical twin - 10%
Both parents - 30%
Monozygotic twin - 30-50%
What is required to develop type 1 diabetes?
Genetic pre-disposition plus:
trigger (perhaps viral infection)
autoimmunity
What is type 1 diabetes characterised by?
Insulin deficiency
What is the clinical presentation of type 1 diabetes?
Short duration of:
thirst (polydipsia)
tiredness (fatigue)
Polyuria/nocturia
Weight loss
Blurred vision
Abdominal pain
What is the medical term for blurred vision?
Myopia
What is seen on examination for type 1 diabetes?
Ketones on breath
Dehydration
May have increased respiratory rate, tachycardia, hypotension
Low grade infections, thrust/balantis
Explain the evolution of type 2 diabetes?
Blood glucose levels increase as B-cell function declines
B cells become damaged by liptoxicity and glucotoxicity as a result of insulin resistance, they can eventually no longer compensate resulting in hyperglycaemia
Is the incidence of type 2 diabetes in Scotland increasing or decreasing?
Increasing
Does the incidence of type 2 diabetes increase or decrease with age?
Increases with age
Explain the genetics of type 2 diabetes for: identical twin, one parent, both parents, sibling, non-identical twin?
Identical twin - 90-100%
One parent - 15%
Both parents - 75%
Sibling - 10%
Non-identical twin - 10%
What are the symptoms of type 2 diabetes?
May have no symptoms
Polydipsia (thirst)
Fatigue
Polyuria/nocturia
Sometimes weight loss
Myopia (blurred vision)
Symptoms of complications such as cardiovascular disease
What are signs of type 2 diabetes?
Not ketogenic
Usually overweight but not always
Low grade infections, thrush/balantitis
May have microvascular or macrovascular complications at diagnosis
When is screening for diabetes in asymptomatic populations done?
When two risk factors are present:
overweight
family history
over age 30 if Maori/Asian
over age 40 if European
previous history of diabetes in pregnancy (gestational diabetes)
had a big baby (>4kg)
inactive lifestyle, lack of exercise
previous high blood glucose/impared glucose tolerance
Other than type 1 and 2, what are other types of diabetes?
Recognised genetic syndromes, such as MODY
Gestational diabetes
Secondary diabetes
What does MODY stand for?
Maturity onset diabetes in the young
Is MODY dominant or recessive?
Autosommal dominant
What are the 2 types of MODY?
Glucokinase mutations
Transcription factor mutaitons
What are the differences between onset, hyperglycaemia, treatment and complications for the 2 types of MODY?
What are some things that secondary diabetes can occur after?
Drug therapy such as corticosteroids
Pancreatic destruction
Recognised genetic syndromes (such as DIDMOAD)
Rare endocrine disorders (such as Cushings syndrome, Acromegaly, pheochromocytoma)
What is gestational diabetes?
Hyperglycaemia during pregnancy
What is gestational diabetes associated with?
Family history of type 2 diabetes
When does gestational diabetes usually develop?
During 2nd or 3rd trimester
What are risk factors for gestational diabetes?
Family history of type 2 diabetes
Overweight
Inactive
What neonatal problems can gestational diabetes cause?
Macrosomia
Respiratory distress
Neonatal hypoglycaemia
what are we checking for when we look at HbA1C levels?
