Is Graves' disease hyperthyroidism or hypothyroidism?

Graves' Disease is a Form of Hyperthyroidism

Graves' disease is definitively a form of hyperthyroidism, characterized by overactivity of the thyroid gland resulting in overproduction of thyroid hormone and increased metabolic rate. 1

Pathophysiology and Diagnosis

Graves' disease is an autoimmune disorder and the most common cause of hyperthyroidism in iodine-sufficient areas, accounting for approximately 95% of hyperthyroidism cases in pregnancy 1. The condition is characterized by:

• Presence of autoantibodies (TRAb) directed against the thyroid stimulating hormone (TSH) receptor that cause overproduction and release of thyroid hormones 2
• Laboratory findings typically show:
  • Low or suppressed TSH
  • Elevated free T4 (FT4) and/or free T3 (FT3) levels 3
  • Positive TSH receptor antibodies (TRAb) 4

Clinical Presentation

The clinical manifestations of Graves' disease reflect the hyperthyroid state and include:

• Tremors and nervousness
• Insomnia and excessive sweating
• Heat intolerance
• Tachycardia and hypertension
• Goiter (enlarged thyroid gland) 1

Distinctive Features of Graves' Disease

Graves' disease has unique features that distinguish it from other causes of hyperthyroidism:

• Ophthalmopathy (occurs in ~50% of patients) with eyelid lag or retraction 1, 4
• Dermal manifestations including localized and pretibial myxedema 1
• Diffuse goiter rather than nodular enlargement 4

Treatment Options

Management of Graves' disease includes three main approaches:

1. Antithyroid Drugs (ATDs):

   • Methimazole is the preferred first-line pharmacological therapy for most patients 3
   • Methimazole is specifically indicated for patients with Graves' disease with hyperthyroidism 5
   • Beta-blockers such as propranolol can be added for symptom control 3

2. Radioactive Iodine Ablation (RAIU):

   • Effective for definitive treatment but results in permanent hypothyroidism 6
   • Contraindicated during pregnancy and breastfeeding 7

3. Surgery (Total or Partial Thyroidectomy):

   • Indicated for patients with intolerance or ineffectiveness of ATDs, large goiters, suspected malignancy, or moderate-to-severe Graves' ophthalmopathy 2
   • Requires preoperative management with ATDs to achieve euthyroid state 2

Special Considerations

Pregnancy

• Methimazole is pregnancy category D
• Propylthiouracil may be preferred in the first trimester due to lower risk of congenital malformations 3
• Close monitoring of thyroid function throughout pregnancy is essential 3

Complications

• Untreated hyperthyroidism can lead to thyroid storm (rare but life-threatening emergency) 1
• Increased risk of severe preeclampsia, preterm delivery, heart failure, and possibly miscarriage if not adequately treated during pregnancy 1

Common Pitfalls

• Misdiagnosing Graves' disease as anxiety or other conditions due to overlapping symptoms
• Inadequate follow-up after initiating treatment
• Failure to recognize extrathyroidal manifestations (ophthalmopathy, dermopathy)
• Not screening for other autoimmune disorders that may coexist with Graves' disease 3

In conclusion, Graves' disease is a specific form of hyperthyroidism with distinctive autoimmune features and requires careful management to prevent complications and improve outcomes.