Sick Euthyroid syndrome
Disturbance of thyroid function by
reduced extrathyroidal T3 production by inhibition of thyroxine 5' deiodinase
Ix
Low T3 +/- low T4 +/- low TSH (drops in T4/TSH related to severity)
(high T4 possible)
Rx
Nil
Thyroxine doesn't help as not converted to T3
Severity of SUS correlates with severity of illness and likely prognosis
- severe illness
- fasting
- chronic malnutrition
- some drugs
reduced extrathyroidal T3 production by inhibition of thyroxine 5' deiodinase
Ix
Low T3 +/- low T4 +/- low TSH (drops in T4/TSH related to severity)
(high T4 possible)
Rx
Nil
Thyroxine doesn't help as not converted to T3
Severity of SUS correlates with severity of illness and likely prognosis