What is the management of hypothyroidism?

Management of Hypothyroidism

Levothyroxine therapy is the first-line treatment for hypothyroidism, with dosing tailored to patient-specific factors and TSH monitoring to achieve optimal levels. 1, 2

Diagnosis and Initial Evaluation

• Serum TSH is the primary screening test for thyroid dysfunction; multiple tests should be done over a 3-6 month interval to confirm abnormal findings 1
• Follow-up testing of serum T4 levels in persons with persistently abnormal TSH levels can differentiate between subclinical (normal T4 levels) and overt (abnormal T4 levels) thyroid dysfunction 1, 2
• High TSH with low free T4 indicates overt primary hypothyroidism, while high TSH with normal free T4 indicates subclinical hypothyroidism 2, 3

Treatment Algorithm

Overt Hypothyroidism

• All patients with overt hypothyroidism should receive levothyroxine therapy 1, 3
• Initial dosing considerations:
  • Young, otherwise healthy patients can start with full calculated dose 3
  • Elderly patients, those with coronary artery disease, or long-standing severe hypothyroidism should start at lower doses (typically 25-50 mcg daily) 4, 3
  • Dosage should be increased gradually, typically by 12.5-25 mcg every 4-6 weeks based on TSH response 4, 3

Subclinical Hypothyroidism

• Treat subclinical hypothyroidism when TSH >10 mIU/L 1, 3
• For TSH between 4.5-10 mIU/L, treatment decisions should consider:
  • Presence of symptoms attributable to hypothyroidism 1
  • Positive anti-thyroid antibodies 3
  • Presence of goiter 3
  • Consider avoiding treatment in adults >85 years with mild TSH elevation 3

Special Populations

• Pregnant women or those planning pregnancy should receive levothyroxine therapy even for subclinical hypothyroidism 1, 4
• TSH should be monitored and levothyroxine dosage adjusted during pregnancy 4
• Postpartum, levothyroxine dosage should return to pre-pregnancy levels 4

Monitoring and Dose Adjustment

• Monitor TSH 6-8 weeks after initiating treatment or changing dose 2
• Target TSH range is typically 0.5-2.0 mIU/L for primary hypothyroidism 3
• Once stable, annual TSH monitoring is recommended 2
• For central (secondary/tertiary) hypothyroidism, maintain free T4 levels in the upper half of the normal range 3

Common Pitfalls and Caveats

• Overdiagnosis is common - many persons labeled with hypothyroidism spontaneously revert to euthyroid state over time 1
• Overtreatment can lead to iatrogenic hyperthyroidism with risks of osteoporosis, fractures, and cardiac complications 1, 3
• For persistent TSH elevation despite adequate levothyroxine dosing, consider:
  • Poor medication compliance 3
  • Malabsorption issues 3
  • Drug interactions affecting levothyroxine absorption 3
• In severe and prolonged hypothyroidism, adrenocortical insufficiency may develop; supplemental adrenocortical steroids may be necessary in these cases 5
• Even with subclinical hypothyroidism, hormone replacement should be considered if fatigue or other hypothyroid symptoms are present 6

Alternative Treatment Considerations

• Levothyroxine monotherapy remains the standard of care 3
• Combination therapy with levothyroxine and liothyronine (T3) has been studied but current evidence does not support routine use 7
• Liothyronine should be used with great caution, particularly in elderly patients or those with cardiovascular disease 5