What are the management options for hyperthyroidism?

Management of Hyperthyroidism

For hyperthyroidism, treatment depends on the underlying cause: use antithyroid drugs (methimazole preferred, propylthiouracil in first trimester pregnancy), radioactive iodine ablation, or thyroidectomy, with beta-blockers for immediate symptom control regardless of definitive therapy chosen. 1, 2

Initial Symptomatic Management

• Beta-blockers (atenolol or propranolol) should be started immediately for symptomatic relief in all patients with hyperthyroidism, particularly those with cardiovascular manifestations like tachycardia and hypertension 1
• In hyperthyroidism associated with thyrotoxicosis, beta-blockers are essential even before definitive treatment is initiated 1, 3
• Non-dihydropyridine calcium channel antagonists (diltiazem or verapamil) are alternatives when beta-blockers are contraindicated 1

Definitive Treatment Based on Etiology

Graves' Disease (70% of cases)

Three treatment options exist, with radioactive iodine being most widely used in the United States: 4, 5, 2

Antithyroid Drugs

• Methimazole is the preferred antithyroid drug for most patients with Graves' disease 2
• Propylthiouracil should be used only in first trimester pregnancy due to risk of severe hepatotoxicity, including hepatic failure requiring transplantation or resulting in death 6
• Standard course is 12-18 months, but recurrence occurs in approximately 50% of patients 5
• Long-term treatment (5-10 years) reduces recurrence to 15% compared to short-term treatment 5
• Higher recurrence risk occurs in patients younger than 40 years, FT4 ≥40 pmol/L, TSH-binding inhibitory immunoglobulins >6 U/L, or goiter size ≥WHO grade 2 5

Radioactive Iodine (131I)

• Most widely used definitive treatment in the United States 2, 7
• Well tolerated with primary long-term sequela being hypothyroidism 4
• Contraindicated in pregnancy, lactation, and Graves' ophthalmopathy (may cause deterioration of eye disease) 4, 5
• Pregnancy must be avoided for 4 months following administration 4
• Corticosteroid cover may reduce risk of ophthalmopathy worsening 4

Surgery (Total or Near-Total Thyroidectomy)

• Reserved for specific indications: large goitre causing compressive symptoms, concurrent thyroid cancer, pregnancy when antithyroid drugs fail, or Graves' ophthalmopathy 4, 3
• Patients must be rendered euthyroid with antithyroid drugs before surgery 4, 3
• Cost-effective with high-volume surgeons 3

Toxic Nodular Goiter (16% of cases)

• Radioactive iodine is the treatment of choice for toxic multinodular goiter 4, 5
• Thyroidectomy is an alternative for those with compressive symptoms or who refuse radioiodine 4
• Antithyroid drugs will not cure toxic nodular goiter and should only be used for temporary control 4
• Radiofrequency ablation is rarely used 5

Toxic Adenoma

• Radioactive iodine or thyroid lobectomy are definitive treatments 3
• Antithyroid drugs provide only temporary control 4

Destructive Thyroiditis (Subacute, Silent, Postpartum)

• Usually mild and self-limited, resolving within weeks with supportive care alone 1, 5
• Beta-blockers for symptomatic relief 1
• Steroids reserved only for severe cases 5
• Most commonly transitions to hypothyroidism, requiring monitoring every 2-3 weeks 1
• Antithyroid drugs are ineffective as this is not due to hormone overproduction 1

Special Populations

Hyperthyroidism in Pregnancy

• Propylthiouracil is preferred in first trimester due to potential fetal abnormalities with methimazole 6
• Consider switching to methimazole in second and third trimesters to avoid maternal hepatotoxicity risk from propylthiouracil 6
• Radioiodine and surgery are contraindicated during pregnancy 4

Hyperthyroidism with Atrial Fibrillation

• Beta-blockers are essential for rate control 1
• Anticoagulation decisions should be guided by CHA2DS2-VASc score, not hyperthyroidism alone 1
• Restoration of euthyroid state often leads to spontaneous conversion to sinus rhythm 1
• Cardioversion and antiarrhythmic drugs generally fail while thyrotoxicosis persists 1

Monitoring During Treatment

For Antithyroid Drug Therapy

• Patients must immediately report sore throat, fever, rash, or signs of hepatic dysfunction (anorexia, pruritus, jaundice, right upper quadrant pain) 6
• White blood cell count with differential if signs of agranulocytosis develop 6
• Liver function tests (bilirubin, alkaline phosphatase, ALT/AST) particularly in first 6 months 6
• Prothrombin time monitoring before surgical procedures due to potential hypoprothrombinemia 6
• Thyroid function tests periodically; elevated TSH indicates need for dose reduction 6

For Thyroiditis

• Monitor thyroid function every 2-3 weeks to detect transition to hypothyroidism 1
• Persistent thyrotoxicosis beyond 6 weeks requires endocrine consultation 1

Severe/Life-Threatening Hyperthyroidism (Grade 3-4)

• Hospitalization for severe cases 1
• Beta-blockers, hydration, and supportive care 1
• Endocrine consultation mandatory 1
• Consider additional therapies including steroids, SSKI, or thionamides (methimazole or propylthiouracil) 1
• Surgery may be necessary in refractory cases 1

Common Pitfalls

• Never use propylthiouracil outside first trimester pregnancy due to severe hepatotoxicity risk, especially in pediatric patients 6
• Do not attempt cardioversion or use antiarrhythmic drugs while patient remains thyrotoxic—restore euthyroid state first 1
• Avoid radioiodine in Graves' ophthalmopathy as it may worsen eye disease 4, 5
• Do not overlook cardiovascular manifestations—beta-blockers should be started immediately to prevent significant cardiovascular events 3
• Recognize that destructive thyroiditis does not respond to antithyroid drugs since it involves hormone release, not overproduction 1, 5