Management of Hyperthyroidism

1. Diagnosis Overview

2. Initial Symptomatic Control (All Causes)

• β-adrenergic blockers (e.g., propranolol 10–40 mg every 6–8 h, or atenolol) — control tachycardia, hypertension, tremor, anxiety. These are temporizing, not curative.

3. Definitive Treatment by Cause

A. Graves Disease

Option 1: Antithyroid Drugs (ATDs)

• Methimazole starting dose: 15–40 mg/day
• PTU starting dose: 100 mg every 8 h (up to 300–600 mg/day in severe cases)
• Thyrotoxic state improves within 3–6 weeks; euthyroidism usually achieved within 12 weeks
• After euthyroidism, dose is reduced (not stopped) and continued for 12–18 months
• Remission rate ~50% with medical therapy; ~50% relapse on stopping
• Caution: PTU carries rare but serious risk of hepatic failure; MMI can cause agranulocytosis (both drugs). Obtain baseline CBC and LFTs before starting.

Option 2: Radioactive Iodine (¹³¹I)

• Most commonly elected definitive therapy
• Cure rate: 75–90% after a single dose (results in euthyroid or hypothyroid state)
• Risk of hypothyroidism: up to 80% at 1 year — patient will require lifelong levothyroxine
• Contraindicated in: pregnancy, breastfeeding, active/severe Graves ophthalmopathy, inability to comply with radiation precautions
• If ATDs were used prior, they should be stopped 3–5 days before ¹³¹I (iodine interferes with uptake)

Option 3: Total Thyroidectomy

• Definitive cure — universal hypothyroidism post-op (patient needs lifelong LT4)
• Indicated for: large goiter with compressive symptoms, suspected malignancy, patient preference, pregnancy (2nd trimester), failure of ATDs/RAI
• Pre-operative preparation: Render euthyroid with ATDs first; add Lugol's iodine (potassium iodide) 10 days pre-op to reduce vascularity and risk of thyroid storm

B. Toxic Multinodular Goiter (TMNG) / Autonomous Nodule

• TRAb negative; ¹²³I scan shows focal uptake
• Surgical resection after thyroid suppression is preferred (rarely malignant; excellent long-term results)
• For patients unable to tolerate surgery: ¹³¹I ablation is an option
• ATDs used as a bridge to surgery/RAI, not for long-term remission

C. Thyroiditis (Subacute, Postpartum, etc.)

• Due to release of preformed hormone, not synthesis — so ATDs and RAI are not indicated
• Focus on β-blockers for symptom control
• NSAIDs or corticosteroids for painful subacute thyroiditis
• Usually self-limiting; monitor for subsequent hypothyroid phase

4. Special Situations

Pregnancy

• ATDs are the only safe option (RAI is absolutely contraindicated)
• PTU preferred in 1st trimester (methimazole associated with aplasia cutis)
• Switch to methimazole in 2nd/3rd trimester (PTU hepatotoxicity risk)
• Use the lowest effective dose to keep maternal FT4 at or slightly above the upper limit of normal (avoid fetal hypothyroidism)

Thyroid Storm

1. PTU (preferred over MMI in storm — also blocks T4→T3 conversion) high-dose
2. Iodine (Lugol's solution or SSKI) — given only after ATDs to block hormone release
3. β-blockers (IV propranolol or esmolol)
4. Corticosteroids (hydrocortisone — blocks T4→T3 conversion, may address relative adrenal insufficiency)
5. Antipyretics (paracetamol; avoid aspirin — displaces T4 from binding proteins)
6. Aggressive IV fluid resuscitation
7. Treat precipitating cause (infection, surgery, trauma)
8. ICU admission + endocrinology consult

For refractory cases: lithium (antithyroid effect) or sodium ipodate (500 mg/day) may be used.

5. Monitoring After Treatment

• Check TSH + free T4 every 4–6 weeks during ATD initiation
• After RAI: monitor every 4–6 weeks for first 6 months, then every 3–12 months
• Post-thyroidectomy: start levothyroxine immediately; check TSH at 6–8 weeks

6. Summary Table

Recent literature note: A 2024 Lancet review (Chaker et al., PMID 38278171) and a 2024 Nature Reviews Endocrinology update on Graves disease (Lanzolla et al., PMID 39039206) are consistent with the above approach; no major paradigm shifts from guidelines.