I had impaired glucose tolerance due to hyperthyroidism. From the list below - thyrotoxicosis aka too much thyroid hormone.
Excerpt from Dr Kaslow's article General lab values..
"GLUCOSE Optimal Range: 85-100 mg/DL
Causes of Increased
* Diabetes mellitus and insulin resistance syndromes
* Thiamine (B1) insufficiency
* Ataxia telangiectasia
* Endocrine hyperfunction (adrenal cortex, pheochromocytoma, acromegaly/ACTH, hypothalamic lesions, Carcinoid, glucagonoma, somatostatinoma, thyrotoxicosis)
* Acute and chronic pancreatitis
* Drugs (anabolic and glucocorticoids, epinephrine, norepinephrine, thiazide diuretics, phenytoin)
Excerpt from Diabetes Wellness article Illness and Diabetes...
"Infection causes a stress response in the body by increasing the amount of certain hormones such as cortisol and adrenaline. These hormones work against the action of insulin and, as a result, the body's production of glucose increases, which results in high blood sugar levels."