Exogenous Insulin Use

[futuredoctor10]

Determing Etiology of Hypoglycemia in Non-Diabetic:

insulinoma: high insulin, elevated C-peptide, high pro-insulin
exogenous insulin use: high insulin, low C-peptide
exogenous sulfonylurea use: high insulin, high C-peptide, low [or] normal pro-insulin

So basically the reason you order pro-insulin is to "rule out" exogenous sulfonylurea use in someone with high insulin and high C-peptide?
Otherwise if you just rely on insulin and C-peptide, both return "high" in someone with insulinoma OR exogenous sulfonylurea use.

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[kaleerkalut]

Determing Etiology of Hypoglycemia in Non-Diabetic:

insulinoma: high insulin, elevated C-peptide, high pro-insulin
exogenous insulin use: high insulin, low C-peptide
exogenous sulfonylurea use: high insulin, high C-peptide, low pro-insulin

So basically the reason you order pro-insulin is to "rule out" exogenous sulfonylurea use in someone with high insulin and high C-peptide?
Otherwise if you just rely on insulin and C-peptide, both return "high" in someone with insulinoma OR exogenous sulfonylurea use.

I thought you can order a urine drug screen to look for sulfonylurea drugs?

 

[futuredoctor10]

I thought you can order a urine drug screen to look for sulfonylurea drugs?

Hmm I have not heard this, but that could very well be correct.

Hopefully someone can clarify...

 

[MrBeauregard]

Hmm I have not heard this, but that could very well be correct.

Hopefully someone can clarify...

Yes, you can test serum or urine for sulfonylureas.

 

[Transposony]

Why are pro-insulin levels low in exogenous sulfonylurea use ?
After-all the insulin is produced endogenously.

 

[MrBeauregard]

Why are pro-insulin levels low in exogenous sulfonylurea use ?
After-all the insulin is produced endogenously.

Pro-insulin levels are actually normal in exogenous sulfonylurea use.

 

[Transposony]

Pro-insulin levels are actually normal in exogenous sulfonylurea use.

I know that but why? What's the mechanism?

 

[futuredoctor10]

Yes, you can test serum or urine for sulfonylureas.

Okay cool. So basically is this correct: Sulfonylureas increase insulin release (resulting in high insulin, high C-peptide) which can look like insulinoma so you either (A) check urine/serum for sulfonylureas or (B) check a pro-insulin which is LOW or NORMAL. Versus in insulinoma, there are high pro-insulin levels.

 

[MrBeauregard]

Okay cool. So basically is this correct: Sulfonylureas increase insulin release (resulting in high insulin, high C-peptide) which can look like insulinoma or so you either (A) check urine/serum for sulfonylureas or (B) check a pro-insulin which is LOW or NORMAL. Versus in insulinoma, there are high pro-insulin levels.

Perfect.

 

[futuredoctor10]

Perfect.

Sweet. Thank you so much for all your help!