How do I manage hyperthyroidism?

Management of Hyperthyroidism

The management of hyperthyroidism should follow a stepwise approach based on severity, with beta-blockers for symptom control, methimazole as first-line antithyroid medication, and consideration of definitive therapy for persistent cases. 1

Initial Evaluation

• Check TSH and Free T4 levels for diagnosis confirmation; T3 can be helpful in highly symptomatic patients with minimal FT4 elevations 1
• Consider TSH receptor antibody testing if clinical features suggest Graves' disease (e.g., ophthalmopathy, T3 toxicosis) 1
• Distinguish between common causes: Graves' disease (70%), toxic nodular goiter (16%), thyroiditis (3%), and drug-induced (9%) 2

Treatment Algorithm Based on Severity

Grade 1 (Asymptomatic or Mild Symptoms)

• Continue immunotherapy if applicable 1
• Initiate beta-blocker (e.g., atenolol 25-50 mg daily or propranolol) for symptomatic relief 1
• Monitor thyroid function every 2-3 weeks to detect transition to hypothyroidism 1
• For persistent thyrotoxicosis (>6 weeks), consider endocrine consultation 1

Grade 2 (Moderate Symptoms)

• Consider holding immunotherapy until symptoms return to baseline 1
• Consider endocrine consultation 1
• Continue beta-blocker therapy 1
• Provide hydration and supportive care 1
• For persistent thyrotoxicosis (>6 weeks), refer to endocrinology for additional workup and possible medical thyroid suppression 1

Grade 3-4 (Severe Symptoms)

• Hold immunotherapy until symptoms resolve 1
• Mandatory endocrine consultation 1
• Continue beta-blocker therapy 1
• Consider hospitalization in severe cases 1
• Inpatient endocrine consultation can guide additional medical therapies including steroids, SSKI, or thionamide (methimazole or propylthiouracil) 1

Medication Selection

Antithyroid Drugs

• Methimazole is the drug of choice for most cases of hyperthyroidism 3, 4, 5

  • Initial dose: 10-30 mg daily as a single dose 4
  • Do not exceed 15-20 mg/day initially to minimize risk of agranulocytosis 3

• Propylthiouracil should be reserved for:

  • First trimester of pregnancy 6, 7, 4
  • Patients with adverse reactions to methimazole 3
  • CAUTION: Propylthiouracil can cause severe liver failure leading to liver transplantation or death 3

Duration of Treatment

• For Graves' disease: 12-18 months of antithyroid drugs with goal of inducing remission 8, 2
• Long-term treatment (5-10 years) is associated with fewer recurrences (15%) compared to short-term treatment (12-18 months) 2
• Remission is unlikely if TSH-receptor antibodies remain above 10 mU/L after 6 months of treatment 3

Definitive Therapy Options

Radioiodine

• Growing use as first-line therapy for hyperthyroidism 8
• Treatment of choice for toxic nodular goiter 8
• Stop antithyroid drugs at least one week prior to radioiodine to reduce risk of treatment failure 3
• Well-tolerated with main long-term risk being radioiodine-induced hypothyroidism 8
• Contraindicated in pregnancy, during lactation, and in children 8
• May worsen Graves' ophthalmopathy (corticosteroid cover may reduce this risk) 8

Surgery (Thyroidectomy)

• Limited but specific role in hyperthyroidism management 8
• Consider for:
  • Large goiter causing compressive symptoms 8
  • Patients who refuse radioiodine 8
• Should be performed as (near) total thyroidectomy 3

Special Considerations

Thyroiditis

• Self-limited condition where initial hyperthyroidism generally resolves in weeks 1
• Often transitions to hypothyroidism or returns to normal 1
• Monitor closely with regular symptom evaluation and free T4 testing every 2 weeks 1
• Introduce thyroid hormone replacement if the patient becomes hypothyroid 1

Pregnancy

• Propylthiouracil is preferred during first trimester due to potential risk of methimazole-associated congenital anomalies 6, 7
• Consider switching from propylthiouracil to methimazole for second and third trimesters due to risk of maternal hepatotoxicity 6, 7

Monitoring

• Monitor thyroid function every 4-6 weeks during routine clinical follow-up 1
• After identification of appropriate maintenance dose, further evaluation required yearly or sooner if patient's status changes 1
• Monitor for side effects of antithyroid drugs, particularly agranulocytosis (sore throat, fever, etc.) and hepatotoxicity 6, 7

Common Pitfalls

• Failure to recognize thyroiditis as a self-limiting condition that typically resolves without specific antithyroid treatment 1
• Overtreatment leading to iatrogenic hypothyroidism 1
• Not adjusting thyroid hormone replacement when TSH is above reference range 1
• Missing the transition from hyperthyroidism to hypothyroidism in thyroiditis 1