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Thyroiditis
Aka: Thyroiditis, Acute Thyroiditis, Painful Thyroiditis, Painless Thyroiditis
- Definitions
- Thyroiditis
- Thyroid Gland Inflammation with or without Thyroid dysfunction
- Labs
- Precautions
- Serum TSH may be falsely increased or decreased by medications and non-Thyroid conditions (See Serum TSH)
- Fluctuating Thyroid function (initial Hyperthyroidism followed by Hypothyroidism) is typical of some Thyroiditis (see below)
- Initial
- Thyroid Stimulating Hormone (TSH)
- Confirmatory
- Free Thyroxine (Free T4)
- Free Triiodothyronine (Free T3)
- Specific tests (as indicated)
- Thyroid peroxidase Antibody (TPO Antibody)
- Increased in Hashimoto's Thyroiditis, Postpartum Thyroiditis, Silent Thyroiditis and Subacute Thyroiditis
- Imaging
- Radioactive Iodine Uptake Scan (RAIU)
- Diffusely increased uptake in Graves Disease
- Decreased overall uptake in Postpartum Thyroiditis, Silent Thyroiditis or Subacute Thyroiditis
- Causes: Most Common
- Hashimoto's Thyroiditis
- Postpartum Thyroiditis
- Subacute Thyroiditis
- Causes: Painful Thyroiditis
- Subacute Granulomatous Thyroiditis or Giant Cell Thyroiditis (uncommon)
- Postviral Thyroiditis with increased Thyroid peroxidase Antibody (TPO Antibody) and low RAIU (Radioactive Iodine uptake)
- Resolves to euthyroid state within 85% of cases (others may continue with Hypothyroidism)
- Suppurative Thyroiditis or Infectious Thyroiditis (rare)
- Presents with Thyroid pain and tenderness, high fever, Leukocytosis and cervical adenopathy
- Most common infectious causes are Streptococcus Pyogenes, Streptococcus Pneumoniae and Staphylococcus aureus
- Radiation-Induced Thyroiditis (1% of I131 patients)
- Presents with transient Hyperthyroidism
- Traumatic Thyroiditis (rare)
- Self-limited Thyroiditis due to local Trauma
- Thyroid Hemorrhage
- Sudden solid Thyroid Nodule bleeding or infarction results in adjacent hemorrhagic cysts
- Even small hemorrhagic Thyroid cysts may cause pain, and in rare cases can cause local compression symptoms (Stridor, Dysphagia)
- Causes: Painless Thyroiditis
- Hashimoto's Thyroiditis (5-10% of cases)
- Chronic Autoimmune Thyroiditis (or Chronic Lymphocytic Thyroiditis)
- Presents as Hypothyroidism (most cases) with a non-tender Goiter
- Thyroid peroxidase Antibody (TPO Antibody) increased
- Postpartum Thyroiditis (5% of cases)
- Hyperthyroidism or Hypothyroidism or initial Hyperthyroidism followed by Hypothyroidism
- Thyroid peroxidase Antibody (TPO Antibody) increased and low RAIU (Radioactive Iodine uptake)
- Drug-Induced Thyroiditis (10% of cases)
- Causes: Amiodarone, Denileukin, Interferon alfa, Interleukin-2, Kinase Inhibitors and Lithium
- Subacute Lymphocytic Thyroiditis or Silent Thyroiditis (uncommon)
- Autoimmune Thyroiditis with increased Thyroid peroxidase Antibody (TPO Antibody) and low RAIU (Radioactive Iodine uptake)
- Resolves to euthyroid state within 85% of cases (others may continue with Hypothyroidism) and rare recurrence
- Riedel's Thyroiditis or Fibrous Thyroiditis (uncommon)
- Firm Goiter which may be associated with local compression (Stridor, Dysphagia)
- Destructive Thyroiditis that may be associated with Hypocalcemia if the Parathyroid Glands are involved
- Causes: By Thyroid function
- Hypothyroidism
- Hashimoto's Thyroiditis
- Riedel's Thyroiditis (euththyroid in 70% of cases)
- Hyperthyroidism
- Radiation-Induced Thyroiditis (transient)
- Graves Disease
- Hyperthyroidism followed by transient or chronic Hypothyroidism (or Hypothyroidism or Hyperthyroidism alone)
- Postpartum Thyroiditis
- Subacute Granulomatous Thyroiditis (Subacute Thyroiditis, Giant Cell Thyroiditis)
- Subacute Lymphocytic Thyroiditis (Silent Thyroiditis)
- Approach: Thyroid pain
- Toxic appearing patient (fever, Leukocytosis, cervical adenopathy)
- Suppurative Thyroiditis or Infectious Thyroiditis
- History or local Radiation Therapy (e.g. I-131) or Trauma
- Radiation-Induced Thyroiditis
- Traumatic Thyroiditis (rare)
- Recent viral illness with decreased Serum TSH (and if ordered, increased Thyroglobulin)
- Subacute Granulomatous Thyroiditis (Subacute Thyroiditis, Giant Cell Thyroiditis)
- Sudden onset of Thyroid pain (with normal Thyroid Function Tests)
- Thyroid Hemorrhage
- Approach: Painless Thyroiditis
- Taking Amiodarone, Denileukin, Interferon alfa, Interleukin-2, Kinase Inhibitors or Lithium?
- Drug-Induced Thyroiditis
- Recent pregnancy (in last year)
- Increased TSH
- Postpartum Thyroiditis (Hypothyroidism phase)
- Hashimoto Thyroiditis
- Decreased TSH with diffusely increased Radioactive Iodine Uptake Scan (RAIU)
- Graves Disease
- Decreased TSH with diffusely decreased Radioactive Iodine Uptake Scan (RAIU)
- Postpartum Thyroiditis (Hyperthyroidism phase)
- Increased TSH
- Hashimoto Thyroiditis
- Subacute Lymphocytic Thyroiditis or Silent Thyroiditis (Hypothyroidism phase)
- Decreased TSH with diffusely increased Radioactive Iodine Uptake Scan (RAIU)
- Graves Disease
- Decreased TSH with diffusely decreased Radioactive Iodine Uptake Scan (RAIU)
- Subacute Lymphocytic Thyroiditis or Silent Thyroiditis (Hyperthyroidism phase)
- Approach: Thyroiditis with Hyperthyroidism
- Step 1: Based on suppressed Serum TSH
- Confirm Hyperthyroidism with Free T4 and Free T3
- Step 2: Consider recent medical history
- Recent illness (Euthyroid Sick Syndrome)
- Malnutrition or Hyponatremia risk factors
- Medications (e.g. Corticosteroids, Opiates, Levodopa)
- Step 3: Consider severity of symptoms (in confirmed Hyperthyroidism with decreased TSH and increased Free T4)
- Consider Beta Blockers (e.g. Propranolol) in significant Hyperthyroidism related symptoms
- Step 4: Distinguish Graves Disease from other Hyperthyroidism causes
- Obtain Radioactive Iodine Uptake Scan (RAIU)
- Course
- Most Thyroiditis follows a triphasic course
- Hyperthyroidism phase
- Preformed Thyroid Hormone released from damaged Thyroid follicular cells
- Hypothyroidism phase
- Follows Thyroid Hormone store depletion
- Euthyroid phase
- Normalization of Thyroid function
- References
- Bindra (2006) Am Fam Physician 73:1769-76 [PubMed]
- Quintero (2021) Am Fam Physician 104(6): 609-17 [PubMed]
- Sweeney (2014) Am Fam Physician 90(6): 389-96 [PubMed]