Abnormal OGTT Results - The many causes
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As often happens, when looking for something a bit more specific, I came across this image at right, which led me to this webpage: Laboratory Testing for Diabetes Mellitus.
Curve 1 is a normal OGTT, Curve 6 is a diabetic. The other causes are listed:
- Hypercorticism - curve 5.
- Acromegaly - between curves 4 and 5
- Hyperthyroidism - curve 4.
- Pheochromacytoma (or "emotional hyperglycemia") - between curves 4 and 5
Pathologic conditions causing flat or depressed glucose tolerance results:
- Insulinoma - Curve 2 or even more depressed
- Intestinal malabsorption - curve 2 or even less of an increase
- Low renal Tm for glucose reabsorption - may be normal curve 1 or may be depressed as in curve 3
- Hypothyroidism - curve 2.
The cite contains a descriptive of each condition. I'm mostly presenting this as an FYI. One thing I was surprised by was the hypothyroid which delays the glucose absorption for a later peak with albeit suppressed glucose levels. Couple hypothyroid with impaired pancreatic function and what do you get? I don't know the answer to this, but can envision that there are a number of people in the community who might have "glucose intolerance" due to a mismatch between absorption, signaling and secretion.