Chempath 14: Diabetes Cases Flashcards
What is the formula for working out osmolarity ?
Osmolarity= 2(Na + k) + urea + glucose
How do you calculate anion gap ?
Anion gap = (Na + K) - (Cl + HC03)
Anion gap calculates how many ‘other” anions there are. E.g PO4
Normally in the body there are some because we are not electrically charged so all anions + all cations should balance.
Which metabolic disturbance is caused by metformin overdose ?
Lactic acidosis
Metformin inhibits gluconeogenesis in the liver by blocking a step in the Cori cycle where lactate is converted back to glucose. This causes excess lactate
Name 2 tests that can be used to diagnose Diabetes or Impaired glucose tolerance ?
Fasting plasma glucose: >7mM = Diabeted
Oral glucose tolerance test: >11.1mM at 2 hours = diabetes
oral glucose tolerance test 7.8-11.1mM at 2 hours = Impaired glucose tolerance
What result defines impaired glucose tolerance ?
Oral glucose tolerance test >7.8 but < 11.1 mM at 2 hours
What result defines impaired fasting glucose ?
Fasting glucose >6.1 but <7.1
What is HHS ?
- Hyperosmolar hyperglycaemic state
- More common in Type 2 DM
- No ketones (because still have insulin)
- very high plasma glucose >30mM
- High osmolarity >320mOsm
- Develops over days
What is DKA?
- Diabetic ketoacidosis
- Ketones in the blood and urine
- more common in type 1 DM
- caused by very low insulin levels
- Hyperglycaemic >11 mM