Euthyroid Sick Syndrome (ESS)

Introduction

• Apparent alterations to thyroid hormone level with normal thyroid gland function
  • peripheral activity of outer ring deiodinase is ↓
    • normally converts T4 to T3
  • peripheral activity of inner ring deiodinase is ↑
    • normally converts T4 to reverse T3
• Likely a response to an acute/chronic illness
  • cancer
  • cardiac disease (MI, CHF)
  • CRF
• sepsis

Evaluation

• Serology 
  • ↓ total serum T4/T3
  • normal serum TSH
  • ↑ reverse T3