What to do if thyroxine (T4) supplementation is wrongly started in thyroiditis?

Management of Incorrectly Started Thyroxine in Thyroiditis

When thyroxine supplementation is incorrectly started in thyroiditis, it should be discontinued immediately and thyroid function tests should be monitored every 4-6 weeks until thyroid function normalizes. 1

Initial Assessment

• Confirm the diagnosis of thyroiditis through clinical presentation (painful or painless thyroid gland), laboratory findings (elevated T4, low TSH, low radioactive iodine uptake), and presence of inflammatory markers 2
• Determine the type of thyroiditis (subacute, silent, or immune checkpoint inhibitor-related) as this affects the management approach 1
• Review the patient's current symptoms to differentiate between hyperthyroidism (from thyroiditis) and iatrogenic hyperthyroidism (from unnecessary thyroxine) 1

Management Algorithm

Step 1: Discontinue Thyroxine

• Immediately stop thyroxine supplementation when thyroiditis is confirmed 1
• Monitor for worsening hyperthyroid symptoms which may occur transiently after discontinuation 3

Step 2: Symptomatic Management

• For symptomatic hyperthyroidism (tachycardia, tremor, anxiety):
  • Initiate beta-blockers (propranolol or atenolol) for symptom control 1
  • Consider prednisolone 0.5 mg/kg for painful thyroiditis to reduce inflammation and accelerate recovery 3
  • Aspirin can be used as an alternative to prednisolone, though recovery may be slower 3

Step 3: Monitoring Protocol

• Check thyroid function tests (TSH, free T4) every 4-6 weeks 1
• Monitor for the natural progression of thyroiditis, which typically follows a triphasic pattern:
  1. Initial hyperthyroid phase (2-8 weeks)
  2. Transient hypothyroid phase (may last several weeks to months)
  3. Return to euthyroid state (in most cases) 2

Step 4: Management Based on Follow-up TFTs

• If persistent hyperthyroidism:

  • Continue beta-blockers for symptom control 1
  • Consider carbimazole only if anti-TSH receptor antibodies are positive (indicating Graves' disease rather than thyroiditis) 1

• If hypothyroidism develops:

  • Monitor without treatment if TSH <10 mIU/L and patient is asymptomatic 4
  • Consider restarting thyroxine only if:
    • TSH >10 mIU/L persists for >6 weeks 4
    • Patient has significant hypothyroid symptoms 4
    • Hypothyroidism persists beyond 6 months (suggesting permanent damage) 2

Special Considerations

For Immune Checkpoint Inhibitor-Related Thyroiditis

• These patients often require higher replacement doses (1.45 mcg/kg/day) if permanent hypothyroidism develops 5
• Consult with oncology before making treatment decisions as thyroid dysfunction may affect cancer therapy 1

For Subacute Thyroiditis

• Prednisolone treatment (rather than aspirin) leads to more rapid normalization of thyroid hormone levels 3
• Even in severe cases with hyperthyroidism, aspirin treatment is effective with no recurrence after withdrawal 3

Common Pitfalls to Avoid

• Failing to recognize thyroiditis: Low radioactive iodine uptake distinguishes thyroiditis from Graves' disease 2
• Premature initiation of thyroxine: The hypothyroid phase of thyroiditis is often transient and self-limiting 2
• Overtreatment with thyroxine: Can lead to iatrogenic hyperthyroidism with risks of osteoporosis, fractures, and cardiac complications 4
• Inadequate monitoring: Thyroid function should be monitored regularly as thyroiditis can progress to permanent hypothyroidism in some cases 1

When to Consult Endocrinology

• Persistent abnormal thyroid function beyond 6 months 1
• Severe symptoms not controlled by first-line measures 1
• Uncertainty about the diagnosis or appropriate management 1
• Complex cases with multiple comorbidities or pregnancy 4