Thyroid Function in Acute Illness

Relationship with Cortisol Levels and Adrenal Gland Size

The American College of Physicians, as reported in the Annals of Internal Medicine, indicates that sick euthyroid syndrome does not cause adrenal gland enlargement, with no evidence of a relationship between the syndrome and adrenal hypertrophy 1, 2, 3
The Endocrine Society, as referenced in the Annals of Internal Medicine, notes that TSH secretion is highly sensitive to factors other than thyroid disorders, including acute illness, which can affect thyroid function test results 1, 2

The American Association of Clinical Endocrinologists, as reported in the Annals of Internal Medicine, recommends that serial TSH measurements are essential to establish that a thyroid disorder is real and persistent, and that morning testing is preferred for more accurate results, especially when assessing adrenal function simultaneously 1, 2
The American College of Physicians, as referenced in Praxis Medical Insights, advises against misinterpreting thyroid function tests during acute illness as primary thyroid dysfunction, and recommends repeating thyroid function tests after resolution of the acute illness 4