What is Diabetes Mellitus? (including Epidemiology of Diabetes) Flashcards
what is diabetes mellitus?
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
symptoms of hyperglycaemia?
polydipsia, polyuria, blurred vision, weight loss, infections
what are the long term complications of hyperglycaemia?
microvascular (retinopathy, neuropathy, nephropathy),
macrovascular (stroke, MI, PVD)
what is the number for diagnosing diabetes with blood glucose level?
fasting 7.0 mmol/l, random 11.1 mmol/l
what is the number for diagnosing diabetes with HbA1c?
≥ 48 mmol/mol.
what group of people is intermediate hyperglycaemia a risk?
identifies a group at higher risk of future diabetes and adverse outcomes such as cardiovascular disease
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.
aetiology of type 1 diabetes?
positive auto antibodies
what are the genetics of type 1 diabetes?
Background population risk ~0.4% If mother has Type 1: 1% risk If father has Type 1: 6% risk If sibling has Type 1: 8% risk If non-identical twin has Type 1: 10% risk If both parents have Type 1: 30% risk Monozygotic twins 30-50% concordance
what does the development of type 1 diabetes mellitus require?
Genetic pre-disposition plus
Trigger e.g.? Viral infection
Auto immunity
symptoms of type 1 diabetes mellitus?
Short duration of Thirst Tiredness Polyuria / nocturia Weight loss Blurred vision Abdominal pain
signs of type 1 DM?
Ketones on breath
Dehydration
May have increased respiratory rate, tachycardia, hypotension.
Low grade infections, thrush / balanitis
genetics of type 2 diabetes?
Identical twin 90-100% risk One parent 15% Both parents 75% Sibling 10% Non-identical twin 10%
symptoms of type 2 diabetes?
May have no symptoms Thirst Tiredness Polyuria / nocturia Sometimes weight loss Blurred vision Symptoms of complications e.g. CVD
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
risk factors for diabetes?
Overweight
• Family history
• Over age 30 years if Maori ⁄ Asian (Indian subcontinent)
⁄ Pacific Island descent
• Over age 40 years if European
• Previous history of diabetes in pregnancy (Gestational Diabetes)
Had a big baby (more than 4 kg)—not in immediate post-natal period
• Inactive lifestyle, lack of exercise
• Previous high blood glucose ⁄ impaired glucose tolerance
what are the other types of diabetes?
Recognised genetic syndromes : MODY
Gestational diabetes
Secondary diabetes
what is maturity onset diabetes in the young?
Autosomal dominant
? 5% of people with diabetes
Impaired beta-cell function
Single gene defect
what are characteristics of glucokinase mutation diabetes?
Onset at birth
Stable hyperglycaemia
Diet treatment
Complications rare
what are characteristics of transcription factor mutation diabetes?
Adolescence/young adult onset
Progressive hyperglycaemia
1/3 diet, 1/3 OHA, 1/3 Insulin
Complications frequent
what is secondary diabetes mellitus?
Drug therapy e.g corticosteroids Pancreatic destruction Haemochromatosis- excess iron deposition Cystic fibrosis Chronic pancreatitis pacreatectomy Recognised genetic syndromes-DIDMOAD Rare endocrine disorders e.g. Cushings syndrome, Acromegaly, Pheochromocytoma
what happens to hyperglycaemia in 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
