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
polyuria
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/HHS
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?
- fasting > 7mmol/L
- random > 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
- glucose > 11.1 mmol/L = 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?
>48mmol/L
What are the diagnostic levels for impaired fasting glucose, OGTT and HbA1c for intermediate hyperglycaemia?
- fasting glucose: 6.1 - 7mmol/L
- ogtt: 7.8 - 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
- risk of microvascular & 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’: low risk of developing diabetes
- intermediate hyperglycemia: higher risk of future diabetes and 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?
- breaks down fat into energy
- lipid triglycerides hydrolysed into glycerol and three fatty acids
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:
- polydipsia
- polyuria/nocturia
- blurred vision
- weight loss
- abdominal pain
- tiredness (fatigue)
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
- polyuria/nocturia
- myopia (blurred vision)
- sometimes weight loss
- fatigue
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
- 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: 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
