Week 4: Diabetes Flashcards
What random plasma glucose level defines diabetes
> 11.1 mmol/L
What fasting plasma glucose level defines diabetes
> 7 mmol/L
What 2h (after oral glucose tolerance test) plasma glucose level defines diabetes
> 11.1 mmol/L
What HbA1c level defines diabetes
> 48 mmol/mol
should repeat and get similar result within 2 weeks
What type of inheritance is MODY
Autosomal dominant
Explain the pathophysiology of MODY
Single gene mutation in gene that creates glucose channels for beta cells
- > more glucose has to enter cell before insulin is secreted
- > insulin secretion remains regulated
Clinical features and complications of MODY
- May be asymptomatic or present like T2DM (hyperglycaemia, polyuria, polydipsia)
- No microvascular complications
What treatment is used for glucokinase MODY
No need treatment for glucokinase MODY
What treatment is used for transcription factor MODY
Sulfonylureas for HNF-1a and HNF-4a MODY
Insulin for HNF-1b MODY
At what age can T1DM be diagnosed
Any age above 6 months old
possible to be diagnosed even after 50yo
What gene is associated with familial risk of developing T1DM
HLA on chromosome 6
What 2 blood markers are used in T1DM? What are they markers for?
C peptide (marker of insulin levels. Cleaved with insulin from proinsulin)
Islet antibodies (marker of B cell response)
Risk factors for developing T2DM
- Family history, obesity, race
- Fat accumulation in liver & pancreas
- Number of hours of being sedentary a day (in spite of activity at other times)
- Previous gestational diabetes
- PCOS
- Socio-economic factors: higher risk in urban areas
Plasma glucose criteria for diagnosis of gestational diabetes
o Fasting glucose 5.6mmol/L OR
o 2h plasma glucose 7.8mmol/L
Who should be screened for gestational diabetes
- BMI >30
- Previous macrosomic baby >4.5kg
- Previous gestational diabetes
- Family history of diabetes
- High risk ethnicities
Clinical features/ complications of neonatal diabetes
- High glucose levels/ DKA
- Low birth weight
- Very low C peptide (low insulin release)
- May lead to transient or permanent diabetes
Pathophysiology of neonatal diabetes
Mutated K-ATPase channel in B cell
B cell cannot depolarised, insulin not released
How might Cushing’s syndrome lead to diabetes
- Cortisol blocks effects of insulin
- Reduced insulin sensitivity in liver and muscle
- Stimulates gluconeogenesis
How might hyperthyroidism lead to diabetes
-T3/T4 stimulates gluconeogenesis and glycolysis
How might acromegaly lead to diabetes
- Growth hormone blocks effects of insulin
- Reduced insulin sensitivity in liver and muscle
- Growth hormone stimulates gluconeogenesis
How might phaeochromocytoma lead to diabetes
- Catecholamines inhibit insulin secretion
- Catecholamines stimulate gluconeogenesis
How might glucagonoma (tumour resulting in overproduction of glucagon) lead to diabetes
-Glucagon stimulates gluconeogenesis
What drugs are commonly associated with higher risk of developing diabetes
- HIV drugs (protease inhibitors and NRTIs)
- steroids
- antipsychotics
Why do HIV drugs (protease inhibitors and NRTIs) cause increased blood sugar
Block uptake of glucose,
Stimulate gluconeogenesis
