Euthyroid Sick Syndrome

Euthyroid Sick Syndrome:
Characterised by abnormal thyroid function tests in clinically euthyroid patients who have a nonthyroidal systemic illness. Any acute illness can cause abnormalities in levels of circulating thyroid hormones, especially if severe  testing may result in erroneous diagnosis of thyroid disorder. Thyroid hormone levels return to normal after illness is over.