Management of Hashimoto’s Thyroiditis – Evidence‑Based Recommendations

Diagnostic Confirmation

Measure serum TSH and free T4 to determine thyroid functional status before initiating therapy. [@1][@2]
Repeat TSH and free T4 testing after 3–6 months to verify persistent abnormalities and exclude transient thyroiditis. [@1][@2]

Initiate levothyroxine replacement immediately in patients with overt hypothyroidism. [@1]
Initial dosing for adults < 70 years without cardiac disease or major comorbidities: start full replacement at ≈ 1.6 µg/kg/day (based on ideal body weight). [@3][@4]
Initial dosing for adults ≥ 70 years or those with cardiac disease/multiple comorbidities: begin with 25–50 µg daily and titrate upward as tolerated. [@3][@4][@5]
Monitor TSH every 6–8 weeks while adjusting dose to achieve a TSH within the laboratory reference range. [@4][@5]
After achieving a stable dose, re‑check TSH every 6–12 months or sooner if symptoms change. [@4][@5]

TSH 4.5–10 mIU/L: do not treat routinely; observe with periodic TSH monitoring. [@1]
Monitor TSH every 6–12 months for progression to overt disease. [@1]
Consider a therapeutic trial of levothyroxine only when the patient has clear hypothyroid symptoms, and continue therapy only if a documented symptomatic benefit is observed. [@1]
The probability of meaningful symptomatic improvement in this TSH range is low; benefits must be weighed against inconvenience, cost, and potential adverse effects. [@1]
TSH > 10 mIU/L: levothyroxine is reasonable because the annual progression rate to overt hypothyroidism is ≈ 5 %. [@1]
Treat symptomatic patients at any TSH elevation. [@4]
In asymptomatic patients, initiate therapy only if TSH remains >10 mIU/L on two measurements at least 4 weeks apart. [@4]

Treat elevated TSH in pregnant women or those planning pregnancy with levothyroxine. [@1]
Obtain a baseline TSH in pregnant patients who have a personal or family history of thyroid disease, goiter, type 1 diabetes, or other autoimmune disorders. [@1]

Use β‑blockers (e.g., atenolol 25–50 mg daily or propranolol) for symptomatic relief of tachycardia or tremor. [@4][@5]
Monitor thyroid function tests every 2–3 weeks to detect the transition from thyrotoxicosis to hypothyroidism. [@4][@5]
The thyrotoxic phase is self‑limited, typically resolving within a few weeks. [@4]
The majority of patients subsequently develop hypothyroidism and will require levothyroxine replacement. [@4]

Initial treatment phase: check TSH and free T4 every 6–8 weeks until the levothyroxine dose is stable. [@4][@5]
Maintenance phase: measure TSH every 6–12 months once the patient is adequately treated. [@4][@5]
Watch for overtreatment: a suppressed TSH may indicate excessive dosing or recovery of thyroid function; reduce or discontinue levothyroxine with close follow‑up. [@3][@4]

Avoid excessive iodine supplementation (e.g., kelp, seaweed) because it can precipitate iodide‑myxedema and worsen hypothyroidism. [@6]
Do not use desiccated thyroid or T3‑containing preparations as first‑line therapy; levothyroxine monotherapy remains the standard, with insufficient evidence to support routine combination therapy except in highly selected cases. [@6]
Recognize that many nonspecific symptoms attributed to hypothyroidism are equally prevalent in euthyroid individuals; distinguish true therapeutic benefit from placebo effect when treating subclinical disease. [@1][@6]