ABIM Exam Review Practice Question of the Week: Excessive urination, thirst and elevated blood glucose
19-year-old thin female presents to your office for excessive urination and thirst she has been experiencing for the past couple of months. You check a fasting blood sugar in the office and find it is 235mg/dL. You are concerned that she may have type 1 diabetes mellitus. Which antibody is most specifically associated with type 1 diabetes mellitus?
A. Anti-endomysial
B. Anti-tissue tranglutaminase
C. Anti-gliadin
D. Anti-glutamic acid decarboxylase
E. Anti-thyroid peroxidase
Explanation
Type 1 diabetes mellitus (DM)—which may present with thin weight, polydipsia and polyuria, as this patient is experiencing—can be associated with other autoimmune diseases such as celiac sprue, myasthenia gravis, thyroid disorders, vitiligo and adrenal disorders. However, for this question, we want the specific antibody that is clinically associated with type 1 DM.
Let’s go through the answer choices.
- Choice A (Anti-endomysial), Choice B (Anti-tissue transglutaminase) and Choice C (Anti-gliadin) are all antibodies that are seen in celiac disease. The most specific of these for gluten hypersensitivity disorder is anti-tissue transglutaminase.
- Choice D (Anti-glutamic acid decarboxylase) is the correct answer as it is most clinically specific for type 1 DM.
- Choice E (Anti-thyroid peroxidase) is seen in Hashimoto’s thyroiditis.
You can see all the previous ABIM Exam Review Questions of the Week at the Knowmedge Blog. You can find also additional topics and questions directly from the Knowmedge Internal Medicine ABIM Board Exam Review Questions QVault.
May 13, 2013
Some other high yield DM topics to know for the boards:
1. Proinsulin is cleaved to make C-Peptide and insulin; In surreptitious insulin use C-Peptide will be low; if Sulfonylurea abuse C-Peptide will be high; If Sulfonylurea level is low or negative consider CT abd/pelvis to look for insulinoma
2. Meds in DM that do NOT cause hypoglycemia: Biguanides (metformin aka glucophage), Alpha glucosidase inhibitors (acarbose), Thiazolidinediones (Rosiglitazone, pioglitazone), Incretin mimetics (exenatide), amylin analogue (pramlintide)
3. Meds in DM that DO cause hypoglycemia: sulfonylureas (glipizide, glyburide, glimepiride), Meglitinides (repaglinide)
4. Diabetes Meds that do not cause weight gain: Metformin, amylin analogue, and incretin drugs
5. If post prandial Accucheck is elevated increase your short acting insulin before meals; If pre prandial Accucheck is elevated increase your long acting insulin