What is the management of hyperthyroidism?

Management of Hyperthyroidism

The management of hyperthyroidism depends on the underlying etiology: for Graves' disease and toxic nodular goiter, use antithyroid drugs (methimazole preferred), radioactive iodine ablation, or thyroidectomy; for thyroiditis-induced thyrotoxicosis, provide supportive care with beta-blockers as symptoms typically resolve spontaneously.

Initial Diagnostic Workup

Before initiating treatment, confirm the etiology of hyperthyroidism:

• Measure TSH, free T4, and free T3 to confirm biochemical hyperthyroidism (suppressed TSH with elevated thyroid hormones) 1, 2
• Check TSH receptor antibodies if Graves' disease is suspected (especially with ophthalmopathy or diffuse goiter) 3
• Obtain thyroid scintigraphy if thyroid nodules are present or the etiology remains unclear 1
• Perform thyroid ultrasonography to evaluate for nodular disease 2

Treatment by Etiology

Graves' Disease and Toxic Nodular Goiter

Antithyroid Drug Therapy (First-Line for Graves' Disease)

• Methimazole is the preferred antithyroid drug due to longer half-life, once-daily dosing, and fewer severe side effects compared to propylthiouracil 4, 5, 6
• Standard course: 12-18 months for Graves' disease 7, 2
• Long-term therapy (5-10 years) reduces recurrence rates to 15% compared to 50% with short-term treatment 2
• Monitor thyroid function every 2-3 weeks initially, then adjust to longer intervals once stable 3
• Check complete blood count and liver function before starting therapy and if symptoms of agranulocytosis develop (sore throat, fever) 4

Propylthiouracil may be used in:

• First trimester of pregnancy (switch to methimazole in second/third trimesters due to hepatotoxicity risk) 4
• Thyroid storm 3
• Patients intolerant to methimazole 5

Radioactive Iodine Ablation

• Most widely used definitive treatment in the United States 5
• Treatment of choice for toxic nodular goiter 7, 2
• Avoid in pregnancy, lactation, and children 7
• Avoid pregnancy for 4 months post-treatment 7
• May worsen Graves' ophthalmopathy—consider corticosteroid prophylaxis in patients with active eye disease 7
• Main long-term consequence: hypothyroidism requiring lifelong levothyroxine replacement 7

Surgical Thyroidectomy

• Reserved for specific indications: large compressive goiter, refusal of radioiodine, or severe ophthalmopathy 7, 5
• Render patient euthyroid with antithyroid drugs before surgery to prevent thyroid storm 7, 5
• Subtotal or near-total thyroidectomy depending on pathology 7

Thyroiditis-Induced Thyrotoxicosis

Supportive Management (Self-Limited Condition)

• Beta-blockers for symptomatic relief (atenolol 25-50 mg daily or propranolol, titrate for heart rate <90 bpm) 3
• Monitor thyroid function every 2 weeks to detect transition to hypothyroidism 3
• Hyperthyroid phase typically resolves within weeks, most commonly progressing to hypothyroidism 3
• High-dose corticosteroids NOT routinely required 3
• Initiate levothyroxine replacement when patient becomes hypothyroid (elevated TSH, low free T4) 3

Symptomatic Management

Beta-Blocker Therapy for All Symptomatic Patients

• Atenolol or propranolol for control of tachycardia, tremor, anxiety, and heat intolerance 3
• Goal: normalize heart rate to reduce tachycardia-mediated cardiac dysfunction 3
• Particularly important in elderly patients and those with cardiovascular disease 3

Severity-Based Approach

Mild Symptoms (Grade 1-2)

• Continue evaluation and treatment as outpatient 3
• Beta-blockers for symptom control 3
• Close monitoring of thyroid function 3

Severe Symptoms (Grade 3-4)

• Hospitalize for severe cases 3
• Endocrine consultation mandatory 3
• Beta-blockers, hydration, and supportive care 3
• Consider additional therapies: steroids, SSKI (saturated solution of potassium iodide), or thionamides under specialist guidance 3
• Surgery may be required for thyroid storm 3

Special Populations

Pregnancy

• Propylthiouracil preferred in first trimester due to lower risk of congenital malformations with methimazole 4
• Switch to methimazole in second and third trimesters to avoid propylthiouracil hepatotoxicity 4
• Use lowest effective dose to maintain maternal free T4 in upper normal range 4
• Many patients experience spontaneous improvement and may discontinue therapy weeks before delivery 4

Elderly and Cardiovascular Disease

• Beta-blockers essential to prevent atrial fibrillation and heart failure 3
• Hyperthyroidism increases cardiovascular mortality risk 3, 1
• Rapid control of hyperthyroidism improves prognosis 2

Monitoring and Follow-Up

• Thyroid function tests every 4-6 weeks during antithyroid drug therapy 3
• Prothrombin time monitoring as methimazole may potentiate anticoagulants 4
• Adjust doses of beta-blockers, digoxin, and theophylline as patients become euthyroid (clearance changes) 4
• Annual thyroid function testing once stable on maintenance therapy 3

Common Pitfalls

• Do not use antithyroid drugs for toxic nodular goiter with expectation of cure—definitive therapy (radioiodine or surgery) is required 7
• Do not overlook agranulocytosis risk—instruct patients to report fever, sore throat, or malaise immediately 4
• Do not administer radioiodine during pregnancy or lactation 7
• Do not start levothyroxine before corticosteroids in central hypothyroidism (hypophysitis)—may precipitate adrenal crisis 3