Thyroiditis: Signs, Symptoms, and Treatment
Clinical Presentation and Symptom Patterns
Thyroiditis typically presents with a triphasic pattern of thyroid dysfunction: initial hyperthyroidism from release of preformed hormone, followed by hypothyroidism as stores deplete, then eventual restoration of normal function—though some patients develop permanent hypothyroidism. 1
Hashimoto Thyroiditis (Chronic Lymphocytic Thyroiditis)
- Presents with or without signs of hypothyroidism, often featuring a painless goiter 1
- Associated with elevated thyroid peroxidase (TPO) antibodies 1, 2
- Occurs in at least 2% of women and represents an organ-specific autoimmune disease 3
- Symptoms of hypothyroidism include fatigue, weight gain, cold intolerance, and constipation 4
- Patients with positive TPO antibodies have a 4.3% annual risk of progressing to overt hypothyroidism versus 2.6% in antibody-negative individuals 5
Subacute (DeQuervain's) Thyroiditis
- Characterized by anterior neck pain and tenderness—the hallmark distinguishing feature 1, 2
- Often follows an upper respiratory viral illness 2
- Presents with suppressed TSH and low radioactive iodine uptake on thyroid scanning 2
- Can cause severe discomfort or complete prostration for weeks to months if untreated 6
- Generalized somatic symptoms accompany the thyroid pain 6
Postpartum Thyroiditis
- Occurs within one year of delivery, miscarriage, or medical abortion 1, 2
- Typically painless, distinguishing it from subacute thyroiditis 3
- Initial hyperthyroid phase may be mistaken for normal postpartum changes or postpartum depression 5
- Diagnosed by new onset of abnormal TSH, abnormal free T4, or both 7
Drug-Induced Thyroiditis
- Amiodarone causes both type I (iodine-induced) and type II (destructive) thyroiditis 5
- Other causative agents include immune checkpoint inhibitors, interleukin-2, interferon-alfa, lithium, and tyrosine kinase inhibitors 1, 8
Treatment Approaches by Thyroiditis Type
Hashimoto Thyroiditis Management
Patients with Hashimoto thyroiditis and overt hypothyroidism require lifelong thyroid hormone therapy with levothyroxine. 1
- Initiate levothyroxine for TSH >10 mIU/L regardless of symptoms, as this carries approximately 5% annual risk of progression to overt hypothyroidism 4
- For patients <70 years without cardiac disease, start with full replacement dose of approximately 1.6 mcg/kg/day 4
- For patients >70 years or with cardiac disease, start with lower dose of 25-50 mcg/day and titrate gradually 4
- Monitor TSH every 6-8 weeks while titrating, then every 6-12 months once stable 4
- Treatment ameliorates hypothyroidism and may reduce goiter size 2
Subacute Thyroiditis Management
Treatment focuses on symptomatic relief, as this is a self-limited inflammatory disease. 1
For Thyroid Pain:
- Nonsteroidal anti-inflammatory drugs (NSAIDs) or salicylates for mild to moderate cases 1, 6
- Corticosteroids (prednisone 40 mg daily) for severe cases, with rapid symptom relief within 24-48 hours 6
- Gradually reduce prednisone dosage over several weeks 6
- Recurrences occur in a small percentage, requiring restoration of higher doses 6
For Hyperthyroid Phase:
- Beta blockers to treat adrenergic symptoms (tachycardia, tremor, anxiety) 1, 2
- Avoid antithyroid drugs—hyperthyroidism results from hormone release, not overproduction 2
For Hypothyroid Phase:
- Treatment generally not necessary unless symptomatic 1
- Consider levothyroxine during transient hypothyroidism, which can usually be discontinued subsequently 6
- Less than 1% develop permanent hypothyroidism requiring lifelong treatment 6
Postpartum Thyroiditis Management
Monitor thyroid function and treat based on severity of dysfunction and symptoms. 7
- Beta blockers for hyperthyroid phase symptoms 2
- Consider levothyroxine in hypothyroid phase if TSH >10 mIU/L, or TSH 4-10 mIU/L with symptoms or fertility concerns 2
- Evaluate TSH and free T4 in women who develop goiter during pregnancy or postpartum 7
- Women with highest TSH levels and anti-TPO antibodies have greatest risk of permanent hypothyroidism 7
- Antibody testing may confirm diagnosis 7
Drug-Induced Thyroiditis Management
- For immune checkpoint inhibitor-induced thyroiditis, continue immunotherapy in most cases—thyroid dysfunction rarely requires treatment interruption 4
- Consider levothyroxine even for subclinical hypothyroidism if fatigue or other symptoms present 4
- Monitor TSH every cycle for first 3 months, then every second cycle 4
- Critical: Rule out concurrent adrenal insufficiency before starting levothyroxine—start corticosteroids first to avoid precipitating adrenal crisis 4, 5
Diagnostic Considerations
Key Distinguishing Features:
- Presence or absence of pain differentiates subacute (painful) from Hashimoto and postpartum (painless) thyroiditis 8
- Radioactive iodine uptake is reduced in viral, radiation-induced, traumatic, autoimmune, or drug-induced thyroiditis 8
- Doppler ultrasound distinguishes thyrotoxicosis (increased blood flow) from destructive thyroiditis (decreased blood flow) 5
- TPO antibodies identify autoimmune etiology and predict progression risk 5, 1
Critical Pitfalls to Avoid:
- Never start thyroid hormone before ruling out adrenal insufficiency in patients with suspected central hypothyroidism or hypophysitis—this can precipitate life-threatening adrenal crisis 4, 5
- Do not treat based on single elevated TSH value—30-60% normalize on repeat testing 4
- Distinguish between transient and permanent hypothyroidism to avoid unnecessary lifelong treatment 4
- In postpartum period, symptoms may be mistaken for normal postpartum changes or depression 5
Surveillance and Follow-Up
In all cases of thyroiditis, surveillance and clinical follow-up are essential to monitor for changes in thyroid function. 1