What are the initial diagnostic labs and treatment options for Graves' disease?

Initial Diagnostic Labs and Treatment Options for Graves' Disease

The initial diagnostic workup for Graves' disease should include TSH as the primary screening test, followed by Free T4 or Free T4 Index (FTI), and thyroid-stimulating hormone receptor antibodies (TRAb) for accurate diagnosis. 1

Diagnostic Evaluation

Initial Laboratory Tests

• TSH: First-line screening test (suppressed in Graves' disease)
• Free T4 or FTI: To confirm hyperthyroidism
• TRAb: Specific for Graves' disease diagnosis
• Thyroid ultrasound: Important diagnostic test to evaluate gland size and vascularity

When test results are uncertain, radionuclide uptake helps distinguish Graves' disease from other causes of hyperthyroidism such as thyroiditis or toxic nodular goiter 2, 3.

Treatment Options

First-Line Treatment

1. Antithyroid Medications:

   • Methimazole is the preferred first-line medication for most patients with Graves' disease 1, 4
   • Initial dosing: 10-40 mg daily based on severity
   • Treatment duration: 12-18 months
   • Goal: Maintain FT4 or FTI in high-normal range using lowest possible dose
   • Monitoring: Every 2-3 weeks initially, then every 4-6 weeks until euthyroid

2. Propylthiouracil:

   • Reserved for specific situations 5:
     • First trimester of pregnancy
     • Patients intolerant to methimazole
     • Patients with severe liver injury

3. Symptomatic Management:

   • Beta-blockers (propranolol or atenolol) for symptomatic relief of tachycardia, tremor, anxiety, and heat intolerance
   • Continue until thyroid hormone levels normalize 1

Alternative Treatment Options

1. Radioactive Iodine (RAI):

   • Treatment of choice in the United States for patients without contraindications 3
   • Contraindicated in:
     • Pregnancy
     • Active/severe orbitopathy
     • Breastfeeding women (must wait four months after treatment)

2. Thyroidectomy:

   • Indicated when:
     • Other treatments fail or are contraindicated
     • Goiter causes compressive symptoms
     • Patient has severe hyperthyroidism
   • Should be performed by an experienced high-volume thyroid surgeon
   • Preparation includes methimazole and potassium iodide solution 1

Monitoring and Follow-up

• Monitor for side effects of antithyroid medications:

  • Agranulocytosis (presents with sore throat and fever)
  • Hepatotoxicity
  • Vasculitis
  • Thrombocytopenia

• Patients should immediately report:

  • Sore throat
  • Fever
  • Rash
  • Symptoms of liver dysfunction

• For pregnant women:

  • Goal is to maintain FT4 in high-normal range using lowest possible dose
  • Close monitoring as thyroid dysfunction may diminish as pregnancy proceeds
  • Physical examination for ophthalmopathy warrants early endocrine referral 6, 1

Special Considerations

Graves' Ophthalmopathy

• Present in approximately 25% of patients 7
• May require specialized treatment independent of hyperthyroidism management
• Selenium supplementation (200 μg daily) recommended for mild Thyroid Eye Disease 1

Pregnancy

• Propylthiouracil preferred in first trimester
• Switch to methimazole after first trimester
• RAI absolutely contraindicated 6

Common Pitfalls to Avoid

1. Failure to monitor for antithyroid medication side effects
2. Inappropriate use of RAI in pregnant women or patients with active orbitopathy
3. Inadequate follow-up and monitoring
4. Overlooking drug interactions
5. Not recognizing that patients with both adrenal insufficiency and hyperthyroidism should be treated for adrenal insufficiency first to avoid precipitating an adrenal crisis 1

The management approach should be guided by disease severity, patient factors, and treatment goals, with the ultimate aim of reducing morbidity and mortality while preserving quality of life.