Figure 5b-2: Patients with severe NTIS were randomized and left untreated or given T4 iv over two weeks. Serum T3, T4, and TSH concentrations are shown for the survivors of the control ( , 1 – 3), and T4-treated ( o, 4 – 6), groups during the study period and at the time of follow-up. The shaded area designates the normal range. Note the prompt recovery of T4 values to the normal range immediately following i.v. treatment with T4. Also note the elevated TSH levels in some patients. T3 levels did not return to normal following T4 treatment for up to two weeks. (Reference 40). Back