Hashimoto's Thyroiditis Management in Young Woman with Improved Clinical Response

Case at a Glance

A 21-year-old Caucasian female with Hashimoto's thyroiditis showing excellent clinical and laboratory response to levothyroxine therapy, with significant improvement in symptoms and normalization of TSH levels.

Patient's Story

The patient is a 21-year-old white female (5'3", 115 lbs) with a history of Hashimoto's thyroiditis diagnosed in 2023. She also has endometriosis managed with oral contraceptives. She has no history of smoking, vaping, or alcohol use. Initially, she experienced classic hypothyroid symptoms including fatigue, sluggishness, and brain fog. After starting levothyroxine therapy, she reports dramatic improvement in energy levels and resolution of cognitive symptoms. She expresses concern about potential dose adjustments as she feels significantly better on her current regimen.

Initial Assessment

Patient presented with elevated TSH of 3.52 mIU/L (reference range 0.27-4.20) in 2024, along with T3 of 119 ng/dL (80-200) and T4 of 1.7 ng/dL (0.8-1.7). Clinical symptoms were consistent with hypothyroidism despite TSH being within normal range.

The Diagnostic Journey

Hashimoto's thyroiditis was diagnosed in 2023, likely based on clinical presentation, elevated TSH, and positive thyroid antibodies (though not specified in current labs). Patient was initially managed by an endocrinologist but transitioned to primary care due to insurance changes.

Final Diagnosis

Hashimoto's thyroiditis (autoimmune hypothyroidism) with good therapeutic response to levothyroxine replacement therapy.

Treatment Plan

Current levothyroxine regimen: 25 mcg daily with additional 25 mcg (total 50 mcg) on Monday, Wednesday, and Friday. Patient also continues oral contraceptive therapy for endometriosis management. Primary care physician is reviewing current labs to determine if dose adjustment is needed.

Outcome and Follow-up

Excellent clinical response with TSH improvement from 3.52 to 1.140 mIU/L (reference range 0.450-4.500) in 2025. Patient reports resolution of fatigue, sluggishness, and brain fog. Current TSH level is well within therapeutic range. Recommendation for continued monitoring with TSH every 3 months. Patient expresses satisfaction with current dose and symptom resolution. Future monitoring should include periodic T3/T4 levels in addition to TSH for comprehensive thyroid function assessment.