What is classified as Graves' disease?

Graves' Disease Classification

Graves' disease is classified as an autoimmune thyroid disorder characterized by hyperthyroidism due to circulating autoantibodies that bind to and stimulate the thyroid hormone receptor (TSHR), resulting in overproduction of thyroid hormones, goiter, and potentially extrathyroidal manifestations. 1

Diagnostic Criteria

• Low thyroid-stimulating hormone (TSH), elevated free thyroxine (FT4) and/or triiodothyronine (T3), and positive TSH receptor antibodies (TRAb) 2
• Diffuse goiter with increased vascularity and hypoechogenicity on ultrasound 1
• Clinical features of hyperthyroidism including weight loss, fatigue, heat intolerance, excessive sweating, diarrhea, tachycardia, insomnia, muscle weakness, and tremor 3

Distinctive Features

• Ophthalmopathy (Graves' eye disease): Present in approximately 50% of patients, characterized by proptosis (bulging eyes), eyelid retraction, and other ocular symptoms 1, 4
• Dermopathy: Rare manifestation presenting as localized and pretibial myxedema 3, 5
• Thyroid bruit: Characteristic physical examination finding that is diagnostic of Graves' disease 3
• Persistent hyperthyroidism: Unlike transient thyroiditis, Graves' disease causes sustained hyperthyroidism due to ongoing autoimmune stimulation of the thyroid 3

Laboratory Findings

• Positive TSH receptor antibodies (TRAb) - the hallmark of Graves' disease 2
• Suppressed TSH with elevated FT4 and/or T3 levels 2
• Some patients may initially test positive for TRAb but later convert to negative while still having active disease 6

Imaging Characteristics

• Thyroid ultrasound typically shows a hypervascular and hypoechoic thyroid gland 2
• Thyroid scintigraphy reveals diffuse and increased radioactive iodine uptake 6
• Color flow Doppler imaging demonstrates increased vascularity throughout the thyroid gland 6

Differential Diagnosis

• Thyroiditis (transient and self-limited hyperthyroidism that resolves in weeks, unlike Graves' disease which is persistent) 3
• Toxic multinodular goiter (nodular rather than diffuse enlargement) 7
• T3 toxicosis (may require specific testing for diagnosis) 3

Treatment Implications

• First-line treatment typically involves antithyroid drugs like methimazole for 12-18 months 2, 7
• Beta-blockers are used for symptomatic relief of tachycardia, tremor, and anxiety 4
• Definitive treatment options include radioactive iodine therapy or thyroidectomy for patients who relapse after completing a course of antithyroid drugs 2
• Special consideration for pregnant women who should switch from methimazole to propylthiouracil during the first trimester 4, 2

Common Pitfalls

• Failing to recognize Graves' disease in patients with atypical presentations such as "apathetic thyrotoxicosis" 5
• Missing the diagnosis when TSH receptor antibody tests are negative despite active disease 6
• Overlooking the transition from hyperthyroidism to hypothyroidism during treatment 4
• Delaying treatment of severe ophthalmopathy, which can lead to permanent vision loss 4

Remember that Graves' disease is a systemic autoimmune disorder that primarily affects the thyroid but can also involve other organs, particularly the eyes, and requires comprehensive evaluation and management to prevent complications and improve quality of life 1, 8.