Management of Thyroiditis
Immediate Assessment: Determine Thyroiditis Type and Thyroid Function Status
The management of thyroiditis depends critically on identifying the specific type (Hashimoto, subacute granulomatous, painless/postpartum, or drug-induced) and the current phase of thyroid dysfunction (hyperthyroid, euthyroid, or hypothyroid). 1, 2
Clinical Features That Distinguish Thyroiditis Types
Hashimoto thyroiditis presents with a painless goiter, often with hypothyroidism at diagnosis, and elevated thyroid peroxidase (TPO) antibodies confirming the autoimmune etiology 1, 2. This is the most common form encountered in clinical practice, affecting at least 2% of women 3.
Subacute granulomatous thyroiditis is characterized by anterior neck pain and tenderness, often following an upper respiratory viral illness, with suppressed TSH and low radioactive iodine uptake 1, 2. The painful, tender thyroid distinguishes this from other forms 4, 5.
Postpartum/painless thyroiditis occurs within one year of delivery, miscarriage, or medical abortion, presenting with a painless goiter and spontaneously reversible hyperthyroidism 1, 2. The postpartum timing is the key diagnostic clue 3.
Drug-induced thyroiditis should be suspected in patients taking amiodarone, immune checkpoint inhibitors, interleukin-2, interferon-alfa, lithium, or tyrosine kinase inhibitors 1, 5. Immune checkpoint inhibitor-induced thyroiditis occurs in 6-20% of patients receiving these agents 6.
Management During the Hyperthyroid (Thyrotoxic) Phase
Symptomatic Treatment with Beta-Blockers
For patients with adrenergic symptoms (palpitations, tremor, anxiety, heat intolerance), initiate propranolol 60-80 mg orally every 4-6 hours or atenolol as first-line therapy. 7 Non-selective beta blockers with alpha receptor-blocking capacity are preferred 6. Target heart rate below 100 bpm with continuous cardiac monitoring in severe cases 7.
Critical: Do NOT Use Antithyroid Drugs
Thyrotoxicosis in thyroiditis results from release of preformed thyroid hormone from damaged follicles, not from increased hormone synthesis 1, 2. Therefore, antithyroid drugs (methimazole, propylthiouracil) are ineffective and should not be used 6. The exception is thyroid storm, where propylthiouracil or methimazole may be used alongside other emergency measures 7.
Pain Management for Subacute Granulomatous Thyroiditis
NSAIDs are first-line therapy for mild to moderate thyroid pain and tenderness. 7 High-dose acetylsalicylic acid or other NSAIDs provide symptomatic relief 2, 5. Systemic glucocorticoids are indicated for severe symptoms, high fever, or pain unresponsive to NSAIDs. 7
Monitoring During Thyrotoxic Phase
Monitor thyroid function (TSH and free T4) every 2-3 weeks during the thyrotoxic phase to detect transition to hypothyroidism. 6, 7 The thyrotoxic phase typically lasts an average of one month after starting immune checkpoint inhibitors, with hypothyroidism developing approximately one month after the thyrotoxic phase 6.
Management During the Hypothyroid Phase
Indications for Levothyroxine Initiation
Start levothyroxine for symptomatic patients with any TSH elevation. 7 Symptoms include fatigue, weight gain, cold intolerance, constipation, and depression 6.
Start levothyroxine for asymptomatic patients with TSH >10 mIU/L. 7 This threshold carries approximately 5% annual risk of progression to overt hypothyroidism 8.
For postpartum thyroiditis specifically, consider levothyroxine in women with TSH >10 mIU/L, or in women with TSH 4-10 mIU/L who are symptomatic or desire fertility 2.
Levothyroxine Dosing Strategy
For patients <70 years without cardiovascular disease, start levothyroxine at 1.6 mcg/kg/day based on ideal body weight. 7 This full replacement dose rapidly normalizes thyroid function 8.
For patients >70 years or with cardiac disease, start levothyroxine at 25-50 mcg/day and titrate gradually. 7 Avoid starting full replacement doses in elderly or cardiac patients due to risk of precipitating arrhythmias or angina 7. Increase by 12.5-25 mcg increments every 6-8 weeks based on TSH response 8.
Monitoring and Dose Adjustment
Recheck TSH and free T4 every 6-8 weeks after any dose adjustment until TSH reaches the target range of 0.5-4.5 mIU/L. 8, 7 Once stable, monitor TSH every 6-12 months or if symptoms change 8.
Reduce or discontinue levothyroxine if TSH becomes suppressed (<0.1-0.45 mIU/L), suggesting overtreatment or recovery of thyroid function. 7 This is particularly important because many cases of thyroiditis result in transient rather than permanent hypothyroidism 1, 2.
Special Considerations by Thyroiditis Type
Hashimoto Thyroiditis (Chronic Lymphocytic Thyroiditis)
Patients with Hashimoto thyroiditis and overt hypothyroidism (elevated TSH with low free T4) require lifelong thyroid hormone therapy. 1 Treatment with levothyroxine ameliorates hypothyroidism and may reduce goiter size 2.
Even with subclinical hypothyroidism (elevated TSH with normal free T4), thyroid hormone replacement should be considered if fatigue or other hypothyroid symptoms are present 8. The presence of elevated TPO antibodies predicts a 4.3% annual progression risk to overt hypothyroidism versus 2.6% in antibody-negative individuals 8.
Postpartum Thyroiditis
Monitor thyroid function every 2-3 months during the first year postpartum to detect the triphasic pattern. 1, 2 Beta blockers treat adrenergic symptoms during the initial hyperthyroid phase 2. In the hypothyroid phase, levothyroxine is indicated for symptomatic women or those with TSH >10 mIU/L 2.
Approximately 30% of women with postpartum thyroiditis develop permanent hypothyroidism and require lifelong levothyroxine 1. Therefore, continue surveillance beyond the first year postpartum 1.
Subacute Granulomatous Thyroiditis
Treatment focuses on symptomatic relief, as this is a self-limited condition. 1, 2 The thyroid gland spontaneously resumes normal hormone production after several months in most cases 2.
NSAIDs or high-dose aspirin provide pain relief 2, 5. Beta blockers manage hyperthyroid symptoms 1. Levothyroxine may be needed during the hypothyroid phase but is often temporary 1. The disorder recurs only in a minority of patients 3.
Drug-Induced Thyroiditis (Immune Checkpoint Inhibitors)
ICI therapy can be continued in most cases of thyroiditis, unlike other immune-related adverse events. 7 High-dose corticosteroids are rarely required for thyroid dysfunction 6, 7.
Monitor thyroid function every 4-6 weeks initially, then every cycle for the first 3 months, then every second cycle thereafter. 6, 7 Conservative management during the thyrotoxic phase is sufficient, with beta blockers for symptomatic patients 6.
Thyroiditis leads to permanent hypothyroidism after an average of 1 month after the thyrotoxic phase and 2 months from initiation of immunotherapy 6. Initiate levothyroxine at the time of hypothyroidism diagnosis 6.
Critical Safety Considerations
Rule Out Adrenal Insufficiency Before Starting Levothyroxine
In patients with suspected central hypothyroidism or hypophysitis, always start physiologic dose steroids 1 week prior to thyroid hormone replacement to prevent life-threatening adrenal crisis. 8 This is particularly important in patients on immune checkpoint inhibitors 6.
Avoid Overtreatment
Approximately 25% of patients on levothyroxine are unintentionally maintained on doses sufficient to fully suppress TSH, increasing risks for atrial fibrillation, osteoporosis, fractures, and cardiac complications 8. Target TSH within the reference range of 0.5-4.5 mIU/L with normal free T4 levels. 8, 7
Distinguish Transient from Permanent Hypothyroidism
Many cases of thyroiditis result in transient hypothyroidism that resolves spontaneously. 1, 2 Failing to distinguish between transient and permanent hypothyroidism leads to unnecessary lifelong treatment 8. Consider reassessing thyroid function after 6-12 months of treatment to determine if levothyroxine can be discontinued 1.
When to Refer to Endocrinology
Endocrinology consultation is recommended in all cases of suspected or confirmed hypophysitis, primary hypothyroidism requiring complex management, hyperthyroidism, thyroiditis with unusual presentations, or difficulty titrating therapy. 6, 7
If the thyrotoxic phase persists beyond 6 weeks, obtain endocrinology consultation to rule out Graves' disease or other causes of persistent hyperthyroidism 7. Additional testing may include thyroid stimulating hormone receptor antibody (TRAb), thyroid stimulating immunoglobulin (TSI), and radioactive iodine uptake scan 6.