kpmle2
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A previously healthy 28-year-old man is brought unconscious to the emergency department. The blood glucose level is found to be 28 mg/dL. After being resuscitated with intravenous glucose, he reports several near-syncopal episodes over the past 6 weeks, each of which was followed by a headache. He also reports a 4.5-kg (1 0-Ib) weight gain. He has no medical history of such events. He denies excessive alcohol intake. His brother-in-law has type 2 diabetes and has begun insulin therapy after oral antihyperglycemic therapy failed.
Laboratory studies:
Serum insulin 42 mU/L
Serum C-peptide 7.2 ng/mL (normal, 0.9 to 4.0 ng/mL)
Serum proinsulin 74 pmol/L (normal, 2.0 to 2.6 pmol/L)
Serum cortisol 30 μg/dL
What diagnostic study is most likely to identify the cause of this patients hypoglycemia?
A. Measurement of serum insulin and proinsulin during a 72-hour fast
B. Measurement of insulin antibodies
C. Urine screening for sulfonylureas
D. Measurement of serum metformin
E. Computed tomography of the abdomen
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| hero
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c
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| Korotkoff
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A
I think the patient has insulinoma.
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| tamerbashir
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insulinoma.
so iam with E
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| jasmin
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a
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| Justice
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Guys, the 72-hour fast will KILL this hypoglycemic person. In addition, the values for these two labs are given.
I go with E. Computed tomography of the abdomen
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| mildus
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e
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| neurom
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Insulinoma. A. 72 h fasting is the most reliable test, CT indicated only after biochemical confirmation of the diagnosis.
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| Ivonne
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Imaging studies only after biochemical diagnosis has been confirmed because 80% of the insulinomas are < 2cm and may not be visible with CT scan.
Will go with A
Edited by Ivonne on 01/13/08 - 09:44 AM
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| drduck
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-- PROTOCOL FOR 72-HOUR FAST
1. Date the onset of the fast as of the last ingestion of calories; discontinue all nonessential medications.
2. The patient may drink calorie-free and caffeine-free beverages.
3. The patient must be active during waking hours.
4. Measure plasma glucose, insulin, C-peptide, and β-hydroxybutyrate (on the same venipuncture specimen) every 6 hours until plasma glucose reaches ≤60 mg/dL (3.3 mM), when frequency should be every 1 to 2 hours.
5. End the fast when the plasma glucose is ≤45 mg/dL (2.5 mM) and the patient has symptoms or signs of hypoglycemia, or plasma glucose is ≤55 mg/dL if Whipple's triad had been demonstrated previously.
6. At the end of the fast, measure plasma glucose, insulin, C-peptide, β-hydroxybutyrate, and sulfonylurea (on the same venipuncture specimen); then inject glucagon, 1 mg intravenously, and measure plasma glucose every 10 minutes three times. After this, feed the patient.
whipples triad.
1-Symptoms known or likely to be caused by hypoglycemia
2-A low glucose measured at the time of the symptoms
3-Relief of symptoms when the glucose is raised to normal
hope this might help..
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| hero
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it will not kill you to check sulfonureas in urine.
Why you are given info abt brother-in-low? some kind of common genes?
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| Ivonne
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hero wrote:
it will not kill you to check sulfonureas in urine.
i think sulfonylureas don't increase pro-insulin because they basically release pre-made insulin. Anyone correct me if i am wrong.
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"The question isn't who is going to let me; it's who is going to stop me. " ~ Ayn Rand
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| doc179
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they do increase proinsulin as c-peptide is the product of cleavage of proinsulin to insulin.
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| Ivonne
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That's right, thanks. It increases both pro-insulin and c peptide. Thanks.
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"The question isn't who is going to let me; it's who is going to stop me. " ~ Ayn Rand
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| multifactorial
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A.72-hour fast
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| kpmle2
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The correct answer is C
Identify appropriate diagnostic tests for evaluation of hypoglycemia.
This patient has inappropriately high insulin, proinsulin, and C-peptide levels in the presence of hypoglycemia. The most important cause of hypoglycemia in the presence of high insulin and C-peptide levels is insulinoma, but factitious causes of hypoglycemia must be ruled out before surgical or medical intervention. Factitious hypoglycemia results from insulin or secretagogues, such as sulfonylurea or meglitinides. A 72-hour fast is not indicated at this time. The critical values for evaluation of hypoglycemia were already obtained by the emergency department physician and showed high insulin and C-peptide levels during an episode of hypoglycemia. Because the elevated C-peptide level rules out factitious insulin use, measurement of insulin antibodies is not likely to have clinical value. Metformin alone does not stimulate insulin secretion and is unlikely to cause recurrent hypoglycemia.
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| drduck
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Q asks which test will be most helpful,
looking at that i feel by going for a 72 hr test one can easily know what exactly is the cause for hypoglycemia, rather than doing all test one by one.
also there is no positive h/o of any factitious disorder....i mean the patient is not a health care professional nor he is having any type of gains.
i feel there is big possibility for a insulinoma.
plz correct me if i m wrong.
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| sherry39
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i wud like to go for aaaa...where is dr clotaire
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| guangyu
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C is a reasonable answer, and i do not think A is the right one because pt already have hign value in hypoglycemia, so if it is not c, the answer should be E
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