Initial Evaluation and Management of Goiter
Begin with serum TSH measurement as the first diagnostic test, followed immediately by thyroid ultrasound in all patients with goiter, regardless of TSH result. 1, 2
Diagnostic Algorithm
Step 1: Measure Serum TSH
- TSH is the most sensitive initial test (98% sensitivity, 92% specificity) and determines the entire diagnostic pathway. 1
- Do not proceed to imaging before obtaining TSH results, as this wastes resources and may lead to unnecessary radiation exposure. 2
Step 2: Perform Thyroid Ultrasound
- Ultrasound is mandatory for all goiter patients to confirm thyroid origin, characterize size and morphology, evaluate nodules, and stratify malignancy risk using ACR TI-RADS criteria. 1, 3
- Ultrasound provides high-resolution imaging superior to all other modalities for structural assessment. 1
- This identifies suspicious nodules requiring biopsy even when thyroid function is abnormal. 2
Step 3: Additional Testing Based on TSH Result
If TSH is Normal (Euthyroid):
- Ultrasound findings guide next steps. 1
- Select nodules for fine-needle aspiration biopsy (FNAB) based on ACR TI-RADS criteria. 1
- Do NOT perform radionuclide scanning in euthyroid patients—it has low positive predictive value for malignancy and does not help determine which nodules to biopsy. 1, 2
If TSH is Low (Thyrotoxic):
- After ultrasound, proceed to radioiodine uptake scan (preferably I-123 over I-131) to differentiate toxic multinodular goiter, toxic adenoma, Graves' disease, or thyroiditis. 2
- The uptake scan directly measures thyroid activity and guides radioactive iodine therapy planning. 2
If TSH is High (Hypothyroid):
- Imaging is generally not indicated, but if performed, ultrasound is appropriate. 2
- Imaging does not differentiate causes of hypothyroidism in adults. 2
Step 4: Evaluate for Compressive Symptoms
If respiratory symptoms, dysphagia, orthopnea, or dysphonia are present:
- Add CT scan to evaluate substernal extension and degree of tracheal compression before considering surgery. 4, 1
- CT is superior to ultrasound for assessing retrosternal extension and defining tracheal compression. 4, 1
- CT is preferred over MRI due to less respiratory motion artifact. 4
Management Approach
Indications for Surgery
- Malignant cytology on FNAB. 3
- Compressive symptoms (dyspnea, choking, dysphagia, airway obstruction) from enlarged goiter. 3, 5
- Suspicious (indeterminate) cytology, unless autonomous function is confirmed by scintigraphy. 3
Observation
- Asymptomatic patients with benign cytology and no compressive symptoms may be observed with periodic neck palpation and ultrasound follow-up. 3
Alternative Treatments
- Radioactive iodine therapy is safe and effective for goiter size reduction and is commonly used in Europe. 3
- Medical therapy with levothyroxine and iodide may be considered for small nodules or goiters, but iatrogenic hyperthyroidism must be avoided. 6
Critical Pitfalls to Avoid
- Never skip TSH measurement before selecting imaging—this leads to inappropriate test selection. 2
- Never perform radionuclide scanning as the initial study or in euthyroid patients with nodules. 1, 2
- Never proceed directly to uptake scan without ultrasound first—this misses coexisting nodules requiring malignancy evaluation. 2
- Never use PET/CT with FDG for initial goiter evaluation—it has no role. 1
- Never delay CT imaging when respiratory symptoms are present—tracheal compression requires urgent assessment. 4, 1