2025 – PAGE 89 – ENDOCRINOLOGY

PREDIABETES

Patients with prediabetes have elevated glucose levels that put them at increased risk of developing diabetes. Prediabetes is diagnosed if testing shows any of the following: an HbA1C 5.7-6.4, impaired fasting glucose (100-125), or impaired glucose tolerance (2-hour OGTT 140-199).

(DOUBLE TAKE) PSEUDOHYPONATREMIA

The short story: PSEUDOHYPONATREMIA results when glucose levels exceed the upper limit of normal by 100. This results in a decrease in sodium by 1.6 for every increase in glucose by 100.

The long story: PSEUDOHYPONATREMIA is a phenomenon that typically refers to the hyperosmolar state caused by hyperglycemia in which the increased oncotic pressure in the extracellular space pulls water from the intracellular space. This dilutes the sodium in the extracellular fluid, resulting in a decreased sodium concentration but possibly normal total body sodium. Pseudohyponatremia can ALSO refer to a situation in which elevated triglycerides or proteins (both are big) cause the measured sodium per overall volume (not sodium per volume of water) to be low. This is likely a low-yield fact, but it could be seen in a nephrotic case with hyperlipidemia.

ACANTHOSIS NIGRICANS

Acanthosis Nigricans represents insulin resistance and is associated with a low HDL and high TGs. Hyperglycemia is less often seen because as insulin sensitivity decreases, insulin production increases to match the need. Hyperglycemia is seen if a patient finally has enough insulin resistance to become diabetic.

METABOLIC SYNDROME

“METABOLIC SYNDROME” = Truncal obesity, low HDL, high TG, high BP ± FBG > 100. Acanthosis nigricans is NOT part of the definition.