Serum thyroid hormone profile in critically Ill children.

Area of Science:

• Pediatric critical care medicine
• Endocrinology
• Clinical biochemistry

Background:

• Critically ill children often exhibit altered thyroid hormone levels, known as non-thyroidal illness syndrome.
• Understanding these changes is crucial for assessing disease severity and predicting outcomes in pediatric intensive care units (PICUs).

Purpose of the Study:

• To investigate the thyroid hormone profile (T3, T4, TSH) in critically ill children.
• To correlate these hormone levels with disease severity and clinical outcomes, including mortality.
• To identify potential predictive markers for survival in this population.

Main Methods:

• Serum levels of total triiodothyronine (T3), thyroxine (T4), and thyroid-stimulating hormone (TSH) were measured in critically ill children upon admission and before discharge or death.
• Patients were categorized into groups based on survival status and compared to controls.
• Disease severity was assessed using the Pediatric Risk of Mortality (PRISM) score.

Main Results:

• Mean T3 levels were significantly lower in critically ill children compared to controls and in those who expired.
• Mean T4 levels were also lower in cases and particularly before death.
• A combined low T3 and T4 was associated with a 30-fold increase in mortality risk. T4 levels at the second measurement and PRISM score were significant predictors of survival.
• Thyroid hormone levels improved in survivors but not in non-survivors.

Conclusions:

• Serum T3 levels serve as an indicator of the patient's current clinical status in critically ill children.
• Serum T4 levels, especially when measured later in the illness course, can predict survival outcomes in this patient group.