What is the treatment for a patient with hypothyroidism, as indicated by elevated TSH and low free T4 levels?

Treatment for Overt Hypothyroidism

Start levothyroxine immediately at 1.6 mcg/kg/day (or 25-50 mcg/day if >70 years or cardiac disease present) to normalize thyroid function and prevent cardiovascular complications. 1

Understanding Your Laboratory Results

Your TSH of 8.61 mIU/L with free T4 of 1.0 (assuming this is in ng/dL, which is low-normal to low) and T3 of 123 (assuming pg/dL, which is low) indicates overt primary hypothyroidism requiring immediate treatment. 1

• TSH >10 mIU/L mandates levothyroxine therapy regardless of symptoms, and your TSH of 8.61 is approaching this threshold with concerning thyroid hormone levels. 1
• The combination of elevated TSH with low-normal to low free T4 confirms inadequate thyroid hormone production. 1, 2
• This carries approximately 5% annual risk of progression to more severe hypothyroidism if untreated. 1

Initial Treatment Protocol

Dosing Strategy

For patients <70 years without cardiac disease:

• Start levothyroxine at full replacement dose of 1.6 mcg/kg/day. 1, 3
• This rapidly normalizes thyroid function and prevents complications. 1

For patients >70 years OR with cardiac disease/multiple comorbidities:

• Start at lower dose of 25-50 mcg/day. 1, 3
• Titrate gradually by 12.5-25 mcg every 6-8 weeks to avoid unmasking cardiac ischemia. 1

Critical Safety Consideration

Before starting levothyroxine, rule out concurrent adrenal insufficiency - starting thyroid hormone before corticosteroids can precipitate life-threatening adrenal crisis. 1, 4, 3

• This is especially important if you have suspected central hypothyroidism, hypophysitis, or autoimmune conditions. 1
• If adrenal insufficiency is present, start physiologic dose steroids 1 week prior to thyroid hormone replacement. 1

Monitoring and Dose Adjustment

Initial Monitoring Phase

• Recheck TSH and free T4 in 6-8 weeks after starting treatment. 1, 3
• Target TSH within reference range of 0.5-4.5 mIU/L with normal free T4 levels. 1
• Adjust dose by 12.5-25 mcg increments based on results. 1

Long-term Monitoring

• Once TSH stabilizes in target range, monitor every 6-12 months. 1, 3
• Recheck sooner if symptoms change or clinical status changes. 1

Expected Outcomes and Benefits

Cardiovascular improvements:

• Treatment prevents progression of cardiac dysfunction, including delayed relaxation and abnormal cardiac output. 1
• Reduces LDL cholesterol and decreases cardiovascular event risk. 1

Quality of life improvements:

• Resolves hypothyroid symptoms including fatigue, cold intolerance, weight gain, constipation, and cognitive impairment. 1, 4
• Symptoms typically improve within 6-8 weeks of adequate replacement. 1

Common Pitfalls to Avoid

Do not delay treatment waiting for TSH to reach 10 mIU/L - your combination of elevated TSH with low thyroid hormones already indicates overt hypothyroidism requiring treatment. 1

Avoid overtreatment - approximately 25% of patients are unintentionally maintained on excessive doses, increasing risk for atrial fibrillation, osteoporosis, and cardiac complications. 1

Do not adjust doses too frequently - wait full 6-8 weeks between adjustments to reach steady state. 1

Take levothyroxine properly:

• On empty stomach, 30-60 minutes before breakfast. 1
• At least 4 hours apart from iron, calcium supplements, or antacids. 1

Special Considerations

If planning pregnancy:

• Optimize thyroid function immediately, targeting TSH <2.5 mIU/L before conception. 1, 3
• Levothyroxine requirements increase 25-50% during pregnancy. 1, 3

If positive anti-TPO antibodies:

• This confirms autoimmune etiology (Hashimoto's thyroiditis) and predicts 4.3% annual progression risk versus 2.6% in antibody-negative individuals. 1
• Treatment is particularly important to prevent progression. 1