Thyroid Hormones in Critical Illness

Crit Care Clin. 2019 Apr;35(2):375-388. doi: 10.1016/j.ccc.2018.11.012. Epub 2019 Jan 24.


Thyroid hormone is integral for normal function, yet during illness, circulating levels of the most active form (triiodothyronine [T3]) decline. Whether this is an adaptive response in critical illness or contributes to progressive disease has remained controversial. This review outlines the basis of thyroid hormone changes during critical illness and considers the evidence regarding T3 replacement.

Keywords: Critical illness; Low T3 syndrome; Non-thyroidal illness syndrom; Sick euthyroid; Thyroid hormone; Triiodothyronine.

Publication types

  • Review

MeSH terms

  • Adrenal Cortex Hormones / therapeutic use*
  • Adult
  • Aged
  • Aged, 80 and over
  • Critical Care / methods*
  • Critical Illness / therapy*
  • Euthyroid Sick Syndromes / diagnosis
  • Euthyroid Sick Syndromes / drug therapy*
  • Euthyroid Sick Syndromes / physiopathology*
  • Female
  • Humans
  • Male
  • Middle Aged
  • Triiodothyronine / therapeutic use*


  • Adrenal Cortex Hormones
  • Triiodothyronine