Frequency of non-thyroidal illness syndrome in pediatric patients with sepsis and septic shock

Abstract

Abstract Background Non-thyroidal illness syndrome (NTIS) is considered when patients demonstrate altered thyroid hormones and is frequently seen in patients with sepsis and septic shock. Levels keep affected with disease progression and usually get normalized after the sickness is cured. NTIS is not studied well in pediatric population. Aim of the work Our primary outcome was to assess the frequency of hormonal changes of NTIS in sepsis and septic shock patients. The secondary outcome was to follow-up the severity of NTIS and its effect on the prognosis of the primary illness. Patients and methods This study (1st phase: cross-sectional, 2nd phase: prospective) included 40 critically ill children categorized into two groups: (i) sepsis group: defined according to standard international criteria using pediatric Sequential Organ Failure Assessment (p SOFA) score and sepsis was considered when p SOFA score > 2; (ii) septic shock group: defined by a vasopressor requirement to maintain a mean arterial pressure ≥ 65 mmHg and having a serum lactate level > 2 mmol/L despite adequate fluid resuscitation, with 20 patients in each group. Patients were admitted to the pediatric intensive care unit (PICU). Thyroid hormone levels were assessed and compared in day 1 and day 5 in all patients and subgroups. All patients were followed up until discharge or death. Results NTIS was found in 47.5% of patients. NTIS was higher among septic shock group than sepsis 65.5% versus 30% (p = 0.027). NTIS was associated with each of ventilation, catecholamines infusion and SOFA score (p = 0.044, 0.027, and 0.033) respectively. FT3 (free triiodothyronine) levels were lower and rT3 (reverse T3) levels were higher in day 5 of sickness than day 1 (p = 0.041 and 0.000) respectively. Furthermore, FT3 levels in day 5 were lower, and rT3 levels in day 1 and day 5 were higher in non-survivors than survivors (p = 0.002, 0.015, and 0.003) respectively. ROC curve was done to assess predictors of mortality and revealed that FT3 levels in day 5 was the best in predicting PICU mortality, followed by SOFA score day 5. Conclusion NTIS is common among critically ill children and higher among septic shock group than sepsis. Also, beside the SOFA score, FT3 measured in day 5 of sickness were the best predictors of PICU mortality.