COMPENDIUM ON FUNCTIONAL MEDICINE - Flipbook - Page 165
Non-Thyroidal Illness Syndrome (NTIS)
Also known as "euthyroid sick syndrome," NTIS reflects alterations in
thyroid function tests due to acute or chronic illness rather than
intrinsic thyroid pathology. Common patterns include:
● Low T3 with normal or low T4 and variable TSH
● Elevated reverse T3
● Recovery phase may show transient TSH elevation
The Rockwell approach emphasizes distinguishing NTIS from true
thyroid dysfunction to avoid inappropriate treatment [14].
Resistance Syndromes
Thyroid hormone resistance syndromes involve genetic mutations
affecting thyroid hormone receptors or transporters, resulting in
variable patterns of thyroid function tests. While rare, these
conditions should be considered in cases with persistently
inconsistent laboratory findings.
Factors Influencing Thyroid Function Test Results
Multiple non-thyroidal factors can significantly impact thyroid
function test results. The Rockwell practitioner should carefully
evaluate for:
Physiological Influences
● Pregnancy: Increases TBG, alters reference ranges for all
thyroid tests
● Aging: May reduce conversion of T4 to T3
● Circadian Rhythms: TSH exhibits diurnal variation with peak
levels at night
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