What is the recommended workup and management for a patient with thyroiditis, distinguishing subacute granulomatous (de Quervain) thyroiditis, Hashimoto thyroiditis, silent thyroiditis, and postpartum thyroiditis?

Workup and Management of Thyroiditis

Initial Diagnostic Approach

Measure TSH, free T4, and ESR (or CRP) as the first-line tests to distinguish among thyroiditis subtypes, then add thyroid peroxidase antibodies (TPO-Ab) and radioactive iodine uptake (RAIU) or thyroid ultrasound with Doppler based on the clinical presentation. 1, 2

Key Clinical Features That Guide Diagnosis

• Neck pain and tenderness point to subacute granulomatous (de Quervain) thyroiditis 1, 2, 3
• Painless presentation suggests Hashimoto thyroiditis, silent thyroiditis, or postpartum thyroiditis 1, 4, 2
• Timing relative to pregnancy (within 12 months of delivery, miscarriage, or abortion) indicates postpartum thyroiditis 1
• Elevated ESR (often >50 mm/hr) is characteristic of subacute granulomatous thyroiditis 2
• Positive TPO antibodies confirm autoimmune etiology in Hashimoto or postpartum thyroiditis 1, 2

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Subacute Granulomatous (de Quervain) Thyroiditis

Diagnostic Confirmation

• Anterior neck pain with thyroid tenderness on palpation 1, 2, 3
• Markedly elevated ESR (typically >50 mm/hr) and elevated thyroglobulin 2
• Suppressed RAIU (<5%) during the thyrotoxic phase distinguishes destructive thyroiditis from Graves disease 5, 2
• Doppler ultrasound shows decreased thyroid blood flow during thyrotoxicosis 5

Management Strategy

For mild-to-moderate symptoms, start NSAIDs (e.g., ibuprofen 600 mg three times daily or aspirin); for severe symptoms with significant pain or systemic illness, initiate prednisone 40 mg daily with gradual taper over 4–6 weeks. 1, 3

Symptomatic Treatment by Phase

• Thyrotoxic phase (1–3 months):

  • Beta-blockers (propranolol 60–80 mg every 4–6 hours or atenolol) for adrenergic symptoms 6, 1
  • Do NOT use antithyroid drugs (methimazole, propylthiouracil)—they are ineffective because thyrotoxicosis results from hormone release, not synthesis 6, 1
  • NSAIDs for mild pain; prednisone 40 mg daily for severe pain, with dose reduction over several weeks 1, 3

• Hypothyroid phase (up to 6 months):

  • Most patients do not require levothyroxine unless symptomatic 1, 7
  • If symptomatic hypothyroidism develops, start levothyroxine at standard replacement doses 1
  • Monitor TSH every 4–6 weeks to detect recovery 6, 1

• Recovery phase:

  • Discontinue levothyroxine once TSH normalizes (typically after 6–12 months) 1, 7
  • Permanent hypothyroidism occurs in <1% of cases 3

Common Pitfalls

• Recurrence occurs in a small percentage of patients; if symptoms return, resume prednisone at higher dose and taper more slowly 3
• Avoid premature steroid discontinuation—taper over 4–6 weeks to prevent relapse 3

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Hashimoto Thyroiditis (Chronic Lymphocytic Thyroiditis)

Diagnostic Confirmation

• Elevated TPO antibodies confirm autoimmune etiology 1, 2
• Painless goiter (may be present or absent) 1, 2
• TSH elevation with low or normal free T4 indicates overt or subclinical hypothyroidism 1, 2
• Thyroid ultrasound shows heterogeneous, hypoechoic parenchyma (not required for diagnosis) 5

Management Strategy

Initiate levothyroxine for overt hypothyroidism (elevated TSH with low free T4) or symptomatic subclinical hypothyroidism (elevated TSH with normal free T4); asymptomatic patients with TSH <10 mIU/L may be monitored without treatment. 8, 1

Treatment Algorithm

• Overt hypothyroidism (TSH elevated, free T4 low):

  • Start levothyroxine 1.6 mcg/kg/day (ideal body weight) in patients <70 years without cardiac disease 8
  • Start 25–50 mcg/day in patients >70 years or with cardiac disease, titrate slowly 8
  • Recheck TSH and free T4 every 6–8 weeks until target TSH 0.5–4.5 mIU/L is achieved 8

• Subclinical hypothyroidism (TSH elevated, free T4 normal):

  • Treat if TSH >10 mIU/L regardless of symptoms 8
  • Treat if TSH 4.5–10 mIU/L with symptoms (fatigue, weight gain, cold intolerance) or positive TPO antibodies 8
  • Monitor TSH every 6–12 months if asymptomatic with TSH 4.5–10 mIU/L 8

• Euthyroid with positive TPO antibodies:

  • Monitor TSH annually—progression to overt hypothyroidism occurs at ~4.3% per year 8

Long-Term Monitoring

• Once stable on levothyroxine, recheck TSH every 6–12 months 8
• Lifelong thyroid hormone therapy is typically required 1, 4

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Silent Thyroiditis (Subacute Lymphocytic Thyroiditis)

Diagnostic Confirmation

• Painless thyroid with thyrotoxicosis 1, 4, 2
• Suppressed RAIU (<5%) during thyrotoxic phase 2
• May have positive TPO antibodies (autoimmune origin) 2
• Doppler ultrasound shows decreased thyroid blood flow 5

Management Strategy

Treat symptomatically with beta-blockers during thyrotoxicosis; monitor TSH every 2–3 weeks to detect transition to hypothyroidism, which typically occurs 1–2 months after onset. 6, 1, 7

Symptomatic Treatment by Phase

• Thyrotoxic phase (1–3 months):

  • Beta-blockers (propranolol or atenolol) for adrenergic symptoms 6, 1
  • Antithyroid drugs are ineffective 6
  • No NSAIDs or steroids needed (painless condition) 1

• Hypothyroid phase (up to 6 months):

  • Start levothyroxine if symptomatic 1, 7
  • Monitor TSH every 4–6 weeks 6

• Recovery phase:

  • Discontinue levothyroxine once TSH normalizes 1, 7
  • Permanent hypothyroidism develops in ~20% of cases 7

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Postpartum Thyroiditis

Diagnostic Confirmation

• Occurs within 12 months of delivery, miscarriage, or medical abortion 1
• Painless thyroid dysfunction (thyrotoxicosis, hypothyroidism, or both) 1, 7
• Positive TPO antibodies in most cases 1
• Suppressed RAIU during thyrotoxic phase 2

Management Strategy

Monitor TSH and free T4 every 4–6 weeks during the first postpartum year in women with goiter or symptoms; treat symptomatically with beta-blockers during thyrotoxicosis and levothyroxine during symptomatic hypothyroidism. 5, 1

Symptomatic Treatment by Phase

• Thyrotoxic phase (1–3 months postpartum):

  • Beta-blockers for adrenergic symptoms 1
  • Antithyroid drugs are ineffective 6
  • Monitor TSH every 2–3 weeks to detect transition to hypothyroidism 6

• Hypothyroid phase (3–6 months postpartum):

  • Start levothyroxine if symptomatic or TSH >10 mIU/L 5, 1
  • Risk of permanent hypothyroidism is highest in women with highest TSH and TPO antibodies 5

• Recovery phase:

  • Attempt levothyroxine discontinuation at 12 months postpartum 1, 7
  • Recheck TSH 4–6 weeks after discontinuation 1
  • Permanent hypothyroidism develops in ~20–30% of cases 7

Special Considerations

• Women with postpartum thyroiditis have 70% recurrence risk in subsequent pregnancies 7
• Screen for thyroid dysfunction in future pregnancies 5

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Surveillance and Follow-Up for All Thyroiditis Types

• Monitor TSH every 2–3 weeks during the thyrotoxic phase to detect transition to hypothyroidism 6, 1
• Monitor TSH every 4–6 weeks during the hypothyroid phase to assess for recovery 6, 1
• Attempt levothyroxine discontinuation after 6–12 months in subacute granulomatous, silent, and postpartum thyroiditis to assess for permanent hypothyroidism 1, 7
• Lifelong surveillance is recommended because late-onset permanent hypothyroidism can occur years after initial recovery 1

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Critical Pitfalls to Avoid

• Never use antithyroid drugs (methimazole, propylthiouracil) for thyroiditis-related thyrotoxicosis—they are ineffective because hormone is released, not synthesized 6, 1
• Do not assume hypothyroidism is permanent without reassessing thyroid function after 6–12 months—many patients recover 1, 7
• Do not miss the transition from thyrotoxicosis to hypothyroidism—monitor TSH every 2–3 weeks during the thyrotoxic phase 6, 1
• Do not overlook postpartum thyroiditis in women with fatigue or mood changes within 12 months of delivery—symptoms overlap with normal postpartum experience 5, 1
• Do not use RAIU or radioiodine therapy during pregnancy or breastfeeding—defer imaging until after breastfeeding cessation 5