Reports:

• Serum TSH is undetectable 
• Serum T3 and T4 are at the upper end of the reference range. 

Risk:

• Atrial fibrillation 
• Osteoporosis

Treatment:

• Radioiodine therapy ( 131I ) or 
• Low dose thionamide. 
• Otherwise, annual review is essential, 

Risk: 

• The conversion rate to overt thyrotoxicosis is 5% each year.