INSUFFICIENCY OF LEVOTHYROXINE THERAPY IN AUTOIMMUNE HYPOTHYROIDISM: EFFECT OF GLUCOCORTICOID ADMINISTRATION

Area of Science:

• Endocrinology
• Immunology

Background:

• Levothyroxine (L-T4) therapy is standard for hypothyroidism.
• Treatment effectiveness can be compromised by factors affecting hormone absorption or binding.

Purpose of the Study:

• To investigate the role of T4-antibodies in levothyroxine treatment non-response.
• To explore potential therapeutic interventions for such cases.

Main Methods:

• Assayed thyroid hormones, TSH, and relevant antibodies (TPO-Ab, TG-Ab, anti-T4 Ab).
• Conducted an L-T4 absorption test.
• Administered intravenous methylprednisolone pulses to a patient with refractory hypothyroidism.

Main Results:

• A patient with Hashimoto thyroiditis and positive anti-T4 antibodies showed clinical hypothyroidism despite medication adherence.
• Methylprednisolone treatment rapidly normalized thyroid hormone levels and reduced anti-T4 antibodies.
• Hypothyroidism recurred upon cessation of methylprednisolone, with a rise in anti-T4 antibodies.

Conclusions:

• Circulating T4-antibodies may cause insufficient levothyroxine effect in autoimmune hypothyroidism.
• Glucocorticoid administration appears effective in overcoming this by releasing FT4 from immune complexes.