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Hashimoto's Thyroiditis
Aka: Hashimoto's Thyroiditis, Hashimoto's Disease, Hashimoto Thyroiditis, Chronic Lymphocytic Thyroiditis, Chronic Autoimmune Thyroiditis, Askenazy Cell, Hurthle Cell
- See Also
- Hypothyroidism
- Thyroiditis
- Epidemiology
- More common in women than men by 3-7 fold
- Age of onset peaks at 40-60 years
- Increased risk with Family History of autoimmune Thyroid disease
- Incidence: 0.3 to 1.5 cases per 1000 persons per year (U.S.)
- Most common Autoimmune Disease worldwide
- Prevalence of Antithyroid Antibody
- Total population: 3-4%
- Euthyroid asymptomatic adolescents: 1.4%
- Middle aged to elderly women: 30-40%
- Pathophysiology
- Chronic autoimmune Thyroid inflammation
- Thyroid infiltration by Lymphocytes as well as Thyroid fibrosis
- Results in formation of Askanazy cells (Hurthle Cells)
- Risk Factors: Hashimoto's with Hypothyroidism
- Excess Iodide intake
- Tobacco Abuse (thiocyanate exposure)
- Symptoms
- See Hypothyroidism
- May initially experience Hyperthyroidism (rarely, hashitoxicosis)
- Generalized Fatigue
- Weight gain
- Cold intolerance
- Diffuse myalgias
- Painless Thyroiditis (painful in rare cases)
- However neck fullness (Goiter) Sensation is common
- Dysphagia may occur (from Goiter related compression)
- Signs
- Hypothyroidism
- Rarely Thyrotoxicosis occurs due to the Thyroid Autoantibody stimulating effects
- Thyroid Goiter (90% of cases)
- Symmetric, diffusely enlarged, non-tender Thyroid
- Firm, irregular Thyroid surface
- Goiter is absent in atrophic form in which fibrosis dominates (with overt Hypothyroidism)
- Labs
- Antithyroid Antibody
- Antithyroid Microsomal Antibody (Thyroid Peroxidase Antibody or TPO Antibody)
- Present in up to 90-95% of Hashimoto cases (and most specific if significantly elevated)
- More mild elevations of TPO Antibody are seen with other thyroid Autoimmunity
- Examples: Postpartum Thyroiditis, Silent Thyroiditis, Subacute Thyroiditis
- Antithyroglobulin Antibody are increased in 60-80% of patients
- TSH-receptor blocking Antibody may be present
- Thyroid function stepwise change
- First: TSH rises
- Next: T4 declines
- Next: T3 decline
- Last: Symptomatic Hypothyroidism
- Associated conditions
- Pernicious Anemia
- Sjogren's Syndrome
- Chronic hepatitis
- Systemic Lupus Erythematosus
- Rheumatoid Arthritis
- Adrenal Insufficiency (Addison Disease)
- Type I Diabetes Mellitus
- Vitiligo
- Hepatitis C (untreated)
- Management
- TSH >10 mU/L
- Levothyroxine starting at 1.6 mcg/kg/day in young, healthy patients
- Indications for Levothyroxine starting at low dose (12.5 to 25 mcg/day)
- Elderly
- Underlying Coronary Artery Disease
- Tachydysrhythmias
- Recheck Serum TSH every 10-12 weeks
- TSH 4.5 to 10 mU/L
- Pregnancy: Levothyroxine
- See Hypothyroidism in Pregnancy for dosing and monitoring frequency
- Other: Variable recommendations on whether to treat
- Consider treatment for positive TPO Antibody and Hypothyroidism symptoms
- If treated
- Start Levothyroxine 25 to 50 mcg daily
- Recheck Serum TSH in 10-12 weeks
- If not treated
- Recheck Serum TSH for overt Hypothyroidism in 6-12 months
- Course
- Initially metabolically normal
- Later Thyroid failure usually ensues
- Thyroid Goiter and symptoms typically resolve by 6 months after becoming euthyroid on replacement
- Complications: Thyroid Cancers
- Primary Thyroid Lymphoma (80 fold increased risk)
- Presents as rapidly growing Thyroid Nodule
- FNA Thyroid Nodule
- Papillary Carcinoma
- References
- Bindra (2006) Am Fam Physician 73:1769-76 [PubMed]
- Dayan (1996) N Engl J Med 335:99-107 [PubMed]
- Quintero (2021) Am Fam Physician 104(6): 609-17 [PubMed]
- Sweeney (2014) Am Fam Physician 90(6): 389-96 [PubMed]