Characteristics of insulin secretion (normal and diabetic) Flashcards
Describe the secretion of insulin in a healthy patient?
A basal level of insulin will be secreted through out the day which will deal with the fasting glucose. This accounts for about 50% of the glucose secreted. Postprandial (after a meal) a top up of insulin will be released to cope with the added glucose from the meal.
How does the secretion of insulin differ with diabetics?
Type 1- insulin is not secreted at all therefore you need to mechanically recreate the insulins basal level and postprandial level.
Type 2- have resistance to insulin and therefore will need drug treatment.
What are the different types of insulin
Rapid acting analogues Short acting Intermediate acting Long acting analogue Mixed
Rapid acting insulin
Works within 2 hours. Should be administered 30 mins before food.
Examples include Humalog, Novorapid, Apidra
Short acting
This is human insulin. It takes longer than the analogues and therefore isnt used as much.
Examples include Humalin, Actrapid, Insuman rapid.
Intermediate acting insulin
Supposedly work for 12 hours- however unlikely that they actually do.
Examples include- Insulatard, Humalin I, Insuman Basal
Long acting analogue
Work for up to 24 hours.
Examples include- lantus, levemir.
Mixed insulin
You can get rapid acting analogue and intermediate mixture. The rapid acting analogue covers the meal times and the intermediate covers the basal.
You can also get short acting, intermediate mix. However this doesn’t have the same efficient short action as the analogue.
Fallbacks of mixed insulin
The mixed insulin actually reacts with each other therefore it is not as effective. The seperate injections work better but arent tolerated as well by patients.
Fallbacks of twice daily insulin
People have to eat regularly- this is ok if the patient is old and has a fixed lifestyle but it isn’t good for younger people.
Fallbacks of insulin pumps
Patients have to calculate their carb intake and then calculate how much insulin to administer.
How to work out how much insulin to give on a newly diagnosed patient.
Weight in kg. Give 0.3 units per kg.
Half of this should be prandial and half should be basal. The prandial can then be subdivided by three to give the three meals a day.
Fasting blood glucose target for diabetics
5-7mmol
Premeal blood glucose
4-7mmol
Post meal (1-2 hours) blood glucose
Less than 10mmol.
Prandial insulins
Rapid insulin analogues:
Onset of action (ideally) 10-15 minutes.
Peak action at 50-90 mins.
Soluble insulin
Onset is 30-60mins.
Peak action at 2-4 hours.
Basal insulins
Intermediate or long acting insulins
Peak activity 4-6 hours after administering
Intermediate analogues
Longer duration of action and less peak activity (smoother curve). Should be given once or twice daily.
When is carbohydrate counting suitable?
For those on mechanical pumps or multiple daily injections (MDI).
How are carbohydrates counted?
1 unit of insulin to every 10g of carbohydrate.
Insulin pumps
Continuous administration of short acting insulin. Deliver basal rate of insulin aswell which can be adjusted to time of day etc. Boost insulin at meal times.
How is diabetes monitored on a daily basis?
Fingerprick testing.
Target HbAC1 level
Less than 48mmol.
However this is quite hard in someone who has had diabetes for a long time therefore try 53mmol or 58mmol
Factors that affect insulin action
Temperature
Injection site
Injection depth
Exercise.
What is lipohypertrophy?
When you inject too much into the same site you get big lumps of fat forming. You can’t then use this as an injections site any longer.
