What is Diabetes Mellitus? Flashcards
What are some symptoms of hyperglycaemia?
- Polydipsia (excessive thirst)
- Polyuria (abnormally large urine production)
- Blurred vision
- Weight Loss
- Infections
Long term microvascular complications of hyperglycaemia?
- Retinopathy
- Neuropathy
- Nephropathy
Long term macrovascular complications of hyperglycaemia?
- Stroke
- MI
- Peripheral vascular disease
What are the normal fasting, random and 2 hour post oral glucose tolerance test blood glucose values?
Normal fasting: < 7 mM
Normal Random: < 11 mM
Normal 2 hour OGTT: < 11 (normal: < 7, Intermediate: 7.8-11)
When diagnosing diabetes based on symptoms and tests, how many rounds of glucose tests are needed to diagnose?
- Typical symptoms + 1 diagnostic test
OR - 2 diagnostic tests (or 1 plus HbA1c)
Diagnostic tests for diabetes?
- Finger prick for hyperglycaemia (not necessarily diabetes)
- Oral glucose tolerance test (OGTT)
- HbA1c
What HbA1c value suggests diabetes?
> 48 mmol/mol
Fasting and 2 hour post OGTT glucose levels that suggest intermediate hyperglycaemia? HbA1c levels?
- Fasting: 6.1 - 7 mmol/L
- 2hr post OGTT: 7.8 - 11 mmol/L
- HbA1c 42 - 47 mmol/mol
What does identification of intermediate hyperglycaemia mean for the patient?
- Increased chance of future diabetes
- Increased chance of CVS disorders
What is HbA1c? What leads to elevated HbA1c levels?
- It is glycosylated haemoglobin, glucose in the blood binds haemoglobin at a specific site forming HbA1c
- Hyperglycaemia, the more glucose in the blood the more HbA1c
How long does HbA1c circulate for? Why is this useful clinically?
- For the lifespan of the RBC
- Means raised HbA1c “reflects the prevailing blood glucose levels from the preceding 2-3 months”
- Glycosylation of RBC’s only occurs when blood glucose is raised consistently for a while, reflects the climate not the weather
When can HbA1c values be misleading for diabetes diagnosis?
- Renal failure
- Hemoglobinopathies
- Anaemia
When can HbA1c not be used to diagnose diabetes?
- Children and young people
- Pregnancy (current or within 2 months)
- Acutely ill patients at risk of diabetes
- Patients taking medication that may cause rapid glucose rise (corticosteroids / antipsychotic drugs)
- Patients with acute pancreatic damage
- Patients with renal failure
- Patients with HIV
Out of the diabetic community, how common are type 1 & 2 diabetes? (what percentage of diabetics has each type)
- 88% Type 2
- 11% Type 1
- 1% Other types of diabetes
How do type 1 and type 2 diabetes vary across age groups?
- Type 1: Evenly spread across age groups, more young people with the condition
- Type 2: Much more common in older individuals
If your father has type 1 diabetes how likely are you to get the condition? Mother? Sibling? Twin?
Father - 6% chance you inherit diabetes
Mother - 1%
Sibling - 8%
Twin - 30-50%
Are you born with type 1 diabetes or is it something you develop?
- Genetic predisposition + Trigger (viral infection?)
- Not 100% sure about this. One website said peak diagnosis age of type 1 in the USA is 14 years old
Symptoms of type 1 diabetes mellitus?
- Thirst
- Tiredness
- Polyuria / nocturia
- Weight loss
- Blurred vision
- Abdominal pain
Signs on clinical examination of type 1 diabetes mellitus?
- Ketones on breath
- Dehydration
- Increased RR, HR & hypotension
- Low grade infections (thrush / balanitis)
How was diabetes tested for prior to blood testing?
- Urine testing
- Two test tubes, one with urine the other with blue Fehling’s solution. Heat them both and combine, if it stays blue no sugar, yellow is some sugar, orange is lots of sugar
Describe the amino acid structure of insulin
- An Alpha chain of 21 AA’s, a beta chain of 30 AA’s and disulphide bonds linking the two together
If one of your parents has type 2 diabetes how likely are you to get the condition? Both parents? Identical twin? Sibling?
- One parent: 15%
- Both parents: 75%
- Identical twin: 90-100%
- Sibling: 10%
Signs of type 2 diabetes?
- Many have no symptoms
- Thirst, tiredness, polyuria, blurred vision, sometimes weight loss
- Often overweight
- Micro / macro - vascular complications
Which ethnicities are more likely to develop diabetes?
- Black Africans
- Chinese
- South Asian
- African-Caribbean
List some conditions that increase the risk of type 2 diabetes
- CVS disease
- Hypertension
- Obesity
- Stroke
- Polycystic ovarian syndrome
- History of gestational diabetes
- Mental health problems
What is MODY? Pathophysiology?
Which genes can be mutated in MODY?
- Maturity Onset Diabetes in the Young
- Single gene defect in beta-cells, autosomal dominant
- Glucokinase mutations OR Transcription Factor Mutations
What is gestational diabetes? What are the risk factors for it?
- Increased insulin resistance during pregnancy resulting in hyperglycaemia, usually disappears after childbirth
- Risk factors include being overweight / inactive & a FH of type 2 diabetes
- Leads to higher chance of type 2 diabetes later in life
What are some neonatal problems associated with gestational diabetes?
- Macrosomia (baby is large when born)
- Respiratory distress
- Neonatal hypoglycaemia
What are some causes of secondary diabetes?
- Major disease of exocrine pancreas (chronic pancreatitis / Haemochromatosis / CF)
- Endocrinopathies (acromegaly / Cushing’s / Glucagonoma / phaeochromocytoma)
- Steroids
