What are the diagnostic criteria and treatment options for a patient with suspected Graves' disease, characterized by symptoms such as weight loss, palpitations, tremors, and exophthalmos?

Diagnosis of Graves' Disease

Diagnose Graves' disease with suppressed TSH plus elevated free T4 and/or T3, confirmed by positive TSH receptor antibodies (TRAb), with radioiodine uptake scan or thyroid ultrasound as adjuncts in ambiguous cases. 1

Diagnostic Algorithm

Initial Laboratory Testing

• Measure TSH, free T4, and T3 levels as the first-line diagnostic approach—low or suppressed TSH with elevated free T4 and/or T3 confirms biochemical hyperthyroidism 1, 2
• Obtain TSH receptor antibodies (TRAb) to confirm autoimmune etiology, as these stimulatory antibodies are the pathogenic hallmark of Graves' disease 1, 2
• Monitor thyroid function every 2-3 weeks after initial diagnosis to track disease progression and guide treatment adjustments 1

Confirmatory Testing When Diagnosis is Ambiguous

• Radioiodine uptake and scan shows diffuse increased uptake throughout the thyroid gland in Graves' disease, distinguishing it from other causes of thyrotoxicosis 1
• Thyroid ultrasound with Doppler demonstrates a diffusely enlarged, heterogeneous, hypervascular gland with increased blood flow, differentiating Graves' from destructive thyroiditis 1, 3
• Additional thyroid antibodies (thyroid peroxidase antibody) may be measured but are less specific than TRAb 4

Clinical Examination Findings

• Look for ophthalmopathy (exophthalmos, lid lag, periorbital edema) or thyroid bruit on auscultation—these physical findings are diagnostic of Graves' disease when present 1
• Assess for thyroid dermopathy (pretibial myxedema), though this occurs rarely 5
• Evaluate cardiovascular manifestations including tachycardia, atrial fibrillation, and signs of high-output heart failure, particularly in elderly patients who may present atypically 5, 6

Distinguishing Graves' Disease from Other Causes of Thyrotoxicosis

The key distinction is between Graves' disease and thyroiditis, as management differs substantially. Thyroiditis presents with thyrotoxicosis but is self-limiting, showing low radioiodine uptake on scan versus the high uptake seen in Graves' disease 4. Doppler ultrasound showing increased thyroid blood flow favors Graves' over thyroiditis 1. TRAb or thyroid stimulating immunoglobulin (TSI) testing helps differentiate these conditions, as these antibodies are positive in Graves' but negative in thyroiditis 4.

Common Pitfalls

• Do not delay treatment while awaiting antibody results if clinical presentation strongly suggests Graves' disease 1
• Failure to evaluate for ophthalmopathy at initial diagnosis is a critical error, as this complication requires specialized management and influences treatment choice 1
• Elderly patients may present atypically with predominantly cardiovascular symptoms (apathetic hyperthyroidism) rather than classic hypermetabolic features, requiring high clinical suspicion 5
• Normal TSH in the first week does not rule out Graves' disease in evolving cases—repeat testing if clinical suspicion remains high 1

Initial Management Considerations

• Initiate beta-blockers (atenolol or propranolol) immediately for symptomatic relief of palpitations, tremors, and anxiety while pursuing definitive diagnosis 1
• Evaluate for complications including ophthalmopathy and cardiac manifestations during the initial assessment, as these influence treatment selection 1
• For severe hyperthyroidism or thyroid storm, hospitalize and administer prednisone 1-2 mg/kg/day along with aggressive beta-blockade 1