Subacute thyroiditis

• Classic Subacute thyroiditis presents as preceding viral
• 2 main subgroups
  • Subacute granulomatous thyroiditis--preceding viral illness (De Quervain's)
  • Subacute lymphocytic thyroiditis--painless, likely autoimmune or postpartum
• 3 phase clinical course
  • Transient hyperthyroid
  • Hypothyroid
  • Spontaneous normalization to euthyroid
• Grave's with rapid turnover
  • High normal percent uptake
  • May need to repeat the scan/uptake at 4 hours after I-123 dose
• Hashimoto's
  • Rarely present with thyrotoxicosis (<5%)
• Factitious thyroiditis
  • Uptake usually low
  
  source:mypacs.com