How do you treat elevated Thyroid-Stimulating Hormone (TSH) levels, specifically severe hyperthyrotropinemia?

From the Guidelines

A TSH level of 98 mIU/L indicates severe hypothyroidism and requires immediate treatment with levothyroxine (synthetic T4) at a dose of approximately 1.6 mcg/kg/d, as estimated using ideal body weight, according to the most recent guidelines 1. The treatment approach should consider the patient's age, frailty, and presence of comorbidities, such as cardiac disease.

• For patients without risk factors (i.e., younger than 70 years old, not frail, and without cardiac disease or multiple comorbidities), full replacement can be estimated using ideal body weight for a dose of approximately 1.6 mcg/kg/d, as suggested by the guidelines 1.
• For those older than age 70 years and/or frail patients with multiple comorbidities (including cardiac disease), consider titrating up from a lower starting dose of 25-50 mcg, as recommended by the guidelines 1. It is essential to monitor the patient's response to treatment and adjust the dose as needed to prevent overtreatment or undertreatment.
• Elevated TSH can be seen in the recovery phase of thyroiditis, and in asymptomatic patients with FT4 that remains in the reference range, it is an option to monitor before treating to determine whether there is recovery to normal within 3-4 weeks, as stated in the guidelines 1.
• Development of a low TSH on therapy suggests overtreatment or recovery of thyroid function, and dose should be reduced or discontinued with close follow-up, according to the guidelines 1. The patient should be educated on the importance of taking levothyroxine on an empty stomach, 30-60 minutes before breakfast or 3-4 hours after the last meal of the day, avoiding calcium, iron supplements, and certain foods which can interfere with absorption. Follow-up blood tests should be done 6-8 weeks after starting treatment to check TSH and T4 levels, with dose adjustments as needed. The extremely high TSH indicates that the thyroid gland is being strongly stimulated to produce more hormone because circulating thyroid hormone levels are very low, which can cause fatigue, weight gain, cold intolerance, constipation, dry skin, and other symptoms, making prompt treatment essential to prevent complications like myxedema coma, which is a life-threatening condition.

From the FDA Drug Label

The general aim of therapy is to normalize the serum TSH level TSH may not normalize in some patients due to in utero hypothyroidism causing a resetting of pituitary-thyroid feedback. Failure of the serum T4 to increase into the upper half of the normal range within 2 weeks of initiation of levothyroxine sodium therapy and/or of the serum TSH to decrease below 20 IU per litre within 4 weeks may indicate the patient is not receiving adequate therapy In adult patients with primary hypothyroidism, monitor serum TSH levels after an interval of 6 to 8 weeks after any change in dosage. In patients on a stable and appropriate replacement dosage, evaluate clinical and biochemical response every 6 to 12 months and whenever there is a change in the patient’s clinical status New onset hypothyroidism (TSH ≥10 IU per liter) 1. 6 mcg/kg/day New onset hypothyroidism (TSH < 10 IU per liter) 1. 0 mcg/kg/day

To treat a TSH of 98, the levothyroxine sodium dosage should be adjusted to normalize the serum TSH level.

• The initial dosage for new onset hypothyroidism with a TSH ≥ 10 IU per liter is 1.6 mcg/kg/day.
• The dosage should be adjusted every 4 weeks until the TSH is within the normal range.
• It is also important to monitor serum T4 levels and adjust the dosage accordingly.
• The patient should be evaluated clinically and biochemically every 6 to 12 months and whenever there is a change in the patient’s clinical status 2

From the Research

Treatment of High TSH Levels

• A TSH level of 98 is significantly elevated, indicating hypothyroidism [(3,4,5,6,7)].
• The primary treatment for hypothyroidism is levothyroxine (LT4) therapy, which aims to normalize serum TSH levels [(3,4,5,6,7)].
• However, some patients may not respond adequately to LT4 monotherapy and may require combination therapy with liothyronine (LT3) [(3,5,6)].
• The decision to treat with combination therapy should be made on a case-by-case basis, considering the patient's symptoms, medical history, and laboratory results [(3,5,6)].

Adjusting Levothyroxine Dosage

• The goal of LT4 therapy is to achieve a normal serum TSH level, which may vary depending on the patient's age and other factors [(4,6,7)].
• For patients under 40 years old, the upper limit of normal for TSH is 3.6 mIU/L, while for patients over 80 years old, it is 7.5 mIU/L 6.
• Adjusting the LT4 dosage to achieve a lower normal TSH level (e.g., 0.1 to 3.0 microU/ml) may help minimize the risk of overmedication and ensure optimal treatment 7.

Alternative Therapies

• Desiccated thyroid extract (DTE) is another form of combination therapy that contains both T4 and T3, but its use is not formally regulated by the FDA 3.
• Some patients may prefer DTE or combination therapy with LT4 and LT3, but these alternatives should be discussed with a healthcare provider to determine the best course of treatment [(3,5,6)].