Thyroid function related symptoms during levothyroxine monotherapy in athyreotic patients

Area of Science:

• Endocrinology
• Thyroidology
• Oncology

Background:

• Levothyroxine (LT4) therapy is standard for athyreotic patients post-thyroidectomy.
• Previous studies noted varying free triiodothyronine (FT3) levels relative to thyroid-stimulating hormone (TSH) in LT4-treated patients.

Purpose of the Study:

• To determine which TSH level group (normal, mildly suppressed, or strongly suppressed) best reflects a preoperative euthyroid state based on subjective symptoms.
• To provide insights into optimal LT4 management following total thyroidectomy.

Main Methods:

• Prospective study of 148 euthyroid papillary thyroid carcinoma patients post-total thyroidectomy.
• Comparison of preoperative and 12-month postoperative subjective symptoms related to thyroid function.
• Categorization of patients based on serum TSH levels: normal, mildly suppressed, and strongly suppressed.

Main Results:

• Patients with strongly suppressed TSH (n=65) reported thyrotoxicosis-like symptoms (heat/cold intolerance, bowel changes, tremors).
• Patients with normal TSH (n=33) reported hypothyroidism-like symptoms (heat/cold intolerance, reduced activity).
• Patients with mildly suppressed TSH (n=50) reported symptoms equivalent to their preoperative euthyroid state.

Conclusions:

• Mildly suppressed TSH levels in LT4-treated patients after total thyroidectomy appear to best approximate preoperative euthyroid status.
• These findings offer valuable guidance for managing thyroid hormone replacement therapy in post-thyroidectomy patients.