Low T3 vs low T3T4 euthyroid sick syndrome in septic shock patients:A prospective observational cohort study

BACKGROUND Both phases of euthyroid sick syndrome(ESS)are associated with worse prognosis in septic shock patients.Although there are still no indications for supplementation therapy,there is no evidence that both phases(initial and prolonged)are adaptive or that only prolonged is maladaptive and requires supplementation.AIM To analyze clinical,hemodynamic and laboratory differences in two groups of septic shock patients with ESS.METHODS A total of 47 septic shock patients with ESS were divided according to values of their thyroid hormones into low T3 and low T3T4 groups.The analysis included demographic data,mortality scores,intensive care unit stay,mechanical ventilation length and 28-day survival and laboratory with hemodynamics.RESULTS The Simplified Acute Physiology Score II score(P=0.029),dobutamine(P=0.003)and epinephrine requirement(P=0.000)and the incidence of renal failure and multiple organ failure(MOF)(P=0.000)were significantly higher for the low T3T4.Hypoalbuminemia(P=0.047),neutrophilia(P=0.038),lymphopenia(P=0.013)and lactatemia(P=0.013)were more pronounced on T2 for the low T3T4 group compared to the low T3 group.Diastolic blood pressure at T0(P=0.017)and T1(P=0.007),as well as mean arterial pressure at T0(P=0.037)and T2(P=0.033)was higher for the low T3 group.CONCLUSION The low T3T4 population is associated with higher frequency of renal insufficiency and MOF,with worse laboratory and hemodynamic parameters.These findings suggest potentially maladaptive changes in the chronic phase of septic shock.

Low Reverse T3: A Reliable, Sensitive and Specific in Diagnosis of Central Hypothyroidism*

Background: Low free T4 and normal/low TSH concentrations are often noted in clinical practice and denote presence of “Euthyroid Sick Syndrome” or Central Hypothyroidism. However, accurate diagnosis is difficult even with determination of free T3 being low/normal in both. Repeated determination of these tests may help differentiate between these disorders. Objective: Evaluation of reverse T3 to differentiate between “Euthyroid Sick Syndrome” and Central Hypothyroidism. Subjects and Methods: Free T3 and Reverse T3 were determined as “add on” tests using previously drawn blood samples of 78 consecutive adults showing low free T4, 0.80 ± 0.02 and low/normal TSH, 1.29 ± 0.40 [normal ranges, 0.89 - 1.70 mcg/dl;0.45 - 4.67 uU/ml]. Free T4, free T3, TSH and reverse T3 levels were also determined in age-matched 35 healthy volunteers and reassessed in study group. Statistical analyses for comparisons were conducted between groups. All data are reported as Mean ± SEM. Results: Reverse T3 established two distinct groups: 1) subnormal concentrations, 8.31 ± 0.52 [range, 11 - 14 ng/dl];2) supernormal levels;32 ± 4 [normal Range 12 - 26]. Free T3 concentrations were subnormal or normal, 1.6 - 2.9 [normal range, 2.3 - 4.2 ng/ml] in individuals amongst both groups. On reassessment after 3 - 6 weeks, free T4, free T3, TSH and reverse T3 normalized in group with normal or elevated reverse T3 indicating recovery from “Euthyroid Sick Syndrome” whereas free T4 and reverse T3 remained subnormal in the other group suggesting presence of Central Hypothyroidism. Conclusion: Reverse T3 is a reliable laboratory test differentiating between Central Hypothyroidism and “Euthyroid Sick Syndrome” in subjects with low free T4 and low/normal TSH levels.