Euthyroid sick syndrome
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief:
Synonyms and keywords: sick euthyroid syndrome; non-thyroidal illness syndrome; low T3 low T4 syndrome
Euthyroid sick syndrome | |
ICD-10 | E07.8 |
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ICD-9 | 790.94 |
MeSH | D005067 |
Overview
Euthyroid sick syndrome is a thyroid hormone disorder where the levels of T3 and/or T4 are at unusual levels, but the thyroid gland does not appear to be dysfunctional.
Historical Perspective
Classification
Pathophysiology
T3 is the biologically active form of thyroid hormone. Normally most of the T3 is produced by peripheral deiodination of circulating T4 by the enzyme 5’-monodeiodinase. In euthyroid sick syndrome there occurs inhibition of the enzyme 5΄-deiodinase and it leads to decrease conversion of T4 to T3.
Causes
Differentiating Euthyroid sick syndrome from Other Diseases
Fasting, starvation, sepsis, trauma, cardiopulmonary bypass, malignancy, heart failure, hypothermia, myocardial infarction, chronic renal failure, cirrhosis, and diabetic ketoacidosis.
Epidemiology and Demographics
Risk Factors
Screening
Natural History, Complications, and Prognosis
Natural History
Complications
Prognosis
Diagnosis
Diagnostic Criteria
History and Symptoms
Physical Examination
Laboratory Findings
Imaging Findings
Other Diagnostic Studies
Treatment
Medical Therapy
Ill patients may have normal to low TSH depending on the spectrum of illness. Total T4 and T3 levels may be altered by binding protein abnormalities, and medications. Reverse T3 are generally increased signifying inhibition of normal Type 1 enzyme or reduced clearance of reverse T3. Measurement of free T4 and/or free T3 levels will be normal.
Surgery
Prevention
External links
- McIver B, Gorman C (1997). "Euthyroid sick syndrome: an overview". Thyroid. 7 (1): 125–32. PMID 9086580.