What is the appropriate treatment for a patient with painful thyroid enlargement and nodules, recent viral infection, radiation of pain to the left ear, normal thyroid peroxidase (TPO) and thyroid‑stimulating hormone receptor (TRAb) antibodies, and a low‑ish thyroid‑stimulating hormone (TSH) that remains within the reference range?

Subacute Thyroiditis: Treat with NSAIDs or Corticosteroids for Pain

This patient has subacute thyroiditis (likely viral/de Quervain's thyroiditis), and treatment should focus on symptomatic relief with NSAIDs as first-line therapy, escalating to corticosteroids if pain persists 1, 2, 3.

Clinical Diagnosis

The presentation is classic for subacute thyroiditis:

• Recent viral infection followed by severe thyroid pain
• Pain radiating to the ear (characteristic referred pain pattern)
• Thyroid swelling and tenderness
• Normal TPO and TRAb antibodies (excludes autoimmune causes like Hashimoto's or Graves disease)
• TSH trending low but still in range (consistent with the initial thyrotoxic phase from follicular disruption releasing preformed hormone)

The negative antibodies are key—they distinguish this from autoimmune thyroiditis 1, 3.

Treatment Algorithm

For Thyroid Pain (Primary Treatment Goal)

First-line: High-dose NSAIDs

• Start with high-dose nonsteroidal anti-inflammatory drugs immediately 2, 3
• This addresses the inflammatory pain that's radiating to the ear

Second-line: Corticosteroids if NSAIDs fail

• If severe pain persists despite NSAIDs, initiate a course of corticosteroids 2, 3
• This is indicated for refractory thyroid pain

For Thyroid Dysfunction

Current hyperthyroid phase (low-normal TSH):

• Beta-blockers for symptomatic relief if the patient has palpitations, tremor, or other adrenergic symptoms 1, 3
• Do NOT use antithyroid drugs—this is destructive thyroiditis with hormone release, not increased synthesis 4

Anticipated hypothyroid phase (will follow in weeks to months):

• Monitor thyroid function every 4-6 weeks 1, 2
• Consider levothyroxine only if symptomatic hypothyroidism develops or TSH becomes significantly elevated
• Most patients don't require treatment during transient hypothyroid phase 1

Expected Disease Course

This is a self-limited triphasic illness 1, 2:

1. Thyrotoxic phase (current): 3-6 weeks of hyperthyroidism from hormone release
2. Hypothyroid phase: Follows as thyroid stores deplete (may last weeks to months)
3. Recovery phase: Thyroid function normalizes in most patients

Critical caveat: Up to 15% develop permanent hypothyroidism, even more than 1 year after presentation 2. Long-term surveillance is essential.

Monitoring Strategy

• Repeat TSH, free T4, and free T3 in 4 weeks initially 4
• Continue monitoring every 3 months until thyroid function stabilizes 4, 1
• Watch for progression to permanent hypothyroidism requiring lifelong replacement

Common Pitfalls to Avoid

1. Don't mistake this for Graves disease or toxic nodular goiter—the negative TRAb and clinical context of post-viral pain distinguish it
2. Don't use antithyroid drugs (methimazole/PTU)—these are contraindicated since this is destructive thyroiditis, not hyperthyroidism from increased hormone synthesis 4
3. Don't assume the nodules are causative—they're likely incidental findings; the acute presentation points to subacute thyroiditis
4. Don't stop monitoring after recovery—permanent hypothyroidism can develop late 2

The thyromegaly and nodules warrant separate evaluation once the acute thyroiditis resolves, but they are not driving the current acute presentation.