How should I approach the management of a patient with subclinical hypothyroidism and elevated TSH levels?

When approaching the management of an adult patient with subclinical hypothyroidism and elevated thyroid-stimulating hormone (TSH) levels, the following steps should be considered:

• Initial Assessment:
  • Consider measuring Thyroid Peroxidase Antibodies (TPOAbs) for adults with TSH levels above the reference range, but do not repeat TPOAbs testing ¹.
  • When discussing whether to start treatment, take into account features that might suggest underlying thyroid disease, such as symptoms of hypothyroidism, previous radioactive iodine treatment or thyroid surgery, or raised levels of thyroid autoantibodies ¹.
• Treatment Considerations (Adults):
  • For TSH of 10 mIU/litre or higher: Consider levothyroxine for adults with subclinical hypothyroidism who have a TSH of 10 mIU/litre or higher on two separate occasions three months apart ¹.
  • For TSH above the reference range but lower than 10 mIU/litre: Consider a six-month trial of levothyroxine for adults under 65 with subclinical hypothyroidism who have a TSH above the reference range but lower than 10 mIU/litre on two separate occasions three months apart, and symptoms of hypothyroidism ¹.
  • If symptoms do not improve after starting levothyroxine, re-measure TSH and adjust the dose if the level remains raised ¹. If symptoms persist when serum TSH is within the reference range, consider stopping levothyroxine ¹.
• Monitoring Untreated Subclinical Hypothyroidism or After Stopping Treatment (Adults):
  • Consider measuring TSH and FT4 once a year if the patient has features suggesting underlying thyroid disease, such as previous thyroid surgery or raised levels of thyroid autoantibodies ¹.
  • Consider measuring TSH and FT4 once every two to three years if the patient has no features suggesting underlying thyroid disease ¹.