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Subacute Granulomatous Thyroiditis

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Subacute Granulomatous Thyroiditis, Granulomatous Thyroiditis, Giant Cell Thyroiditis, Subacute Thyroiditis, de Quervain's Thyroiditis, de Quervain Thyroiditis

  • Definition
  1. Painful Thyroiditis associated with Viral Infection
  • Epidemiology
  1. Incidence: 5 per 100,000 persons
    1. Most common cause of Painful Thyroiditis
  2. Peak Incidence between ages 40 to 50 years
  3. More common in women by 4 fold
  4. Peak onset in late summer and early fall months
  • Pathophysiology
  1. Associated with HLA-B35
  2. Thyroiditis associated with viral infection
    1. Coxsackievirus
    2. Echovirus
  3. Activated T-Lymphocytes injure Thyroid follicular cells (destructive Thyroiditis)
    1. Results in the initial T4 and T3 unbridled increase
    2. Ultimately T4 and T3 falls when stores are exhausted
  • Symptoms
  1. Upper Respiratory Infection within prior 30 days (recalled by 25% of patients)
  2. Prodrome
    1. Myalgias
    2. Low-grade fever
    3. Pharyngitis
  3. Anterior Neck Pain in Thyroid region
    1. Hallmark symptom and often presenting complaint
    2. Tender, swollen Thyroid Gland and adjacent neck with radiation into jaw in some cases
  4. Associated symptoms
    1. Local compressive symptoms (e.g. Dysphagia)
    2. Hyperthyroidism symptoms (e.g. sweating, Tremor, weight loss)
  • Signs
  1. Diffusely enlarged Thyroid
  2. No Proptosis (contrast with Grave's Disease)
  3. No pretibial Myxedema (contrast with Grave's Disease)
  • Stages
  • Triphasic
  1. Phase 1: Hyperthyroidism (initial 4 to 8 weeks)
  2. Phase 2: Hypothyroidism (weeks to months)
    1. May persist indefinately (in up to 15% of cases)
    2. May require longterm Thyroid Replacement
  3. Phase 3: Euthyroid
    1. Thyroid function normalizes by 6-12 months (up to 18 months) in 85% of cases
  • Differential Diagnosis
  1. See Painful Thyroiditis
  2. Suppurative Thyroiditis or Infectious Thyroiditis (rare)
    1. Associated with high fever, Leukocytosis and signs of toxicity
    2. FNA for culture and Gram Stain if suspected
  3. Radiation-Induced Thyroiditis (1% of I131 patients)
  4. Traumatic Thyroiditis (rare)
  5. Thyroid Hemorrhage
  • Labs
  1. Thyroid Function Tests (variable depending on phase)
    1. Thyroid Stimulating Hormone (TSH)
    2. Free T4
  2. Acute phase reactants
    1. Erythrocyte Sedimentation Rate (ESR) >50 mm/hour
    2. C-Reactive Protein (CRP)
    3. Complete Blood Count
      1. Mild Leukocytosis
      2. Mild Anemia
  3. Thyroid antibodies and other Thyroid studies
    1. Thyroid stimulating Antibody negative (contrast with Grave's Disease)
    2. Thyroid peroxidase Antibody or TPO Antibody positive (but at lower levels than with Hashimoto Thyroiditis)
    3. Thyroglobulin level increased
  • Imaging
  1. Radioiodine Uptake (RAIU)
    1. Decreased uptake diffusely to <1-2% (unlike Grave's Disease in which the uptake is increased diffusely)
  2. Thyroid Ultrasound
    1. Nonuniform echotexture throughout the Thyroid Gland (contrast with cystic or solid mass in Hemorrhage or Infectious Thyroiditis)
  • Management
  1. Thyroid pain (may persist for 5 weeks from onset)
    1. NSAIDs (inital medication)
      1. Ibuprofen 600 mg every 6 hours as needed
    2. Prednisone 40-60 mg orally daily for 5-7 days, then taper over 4 weeks
      1. Indicated if pain refractory to NSAIDs after 4-7 days on NSAIDs
      2. Pain relieved in most cases by 48 hours
      3. Not preventive of Thyroid dysfunction or longterm Hypothyroidism
  2. Hyperthyroidism symptoms
    1. See Hyperthyroidism for symptomatic treatment
    2. Beta Blocker (e.g. Propranolol) may be used for symptomatic management
  3. Hypothyroidism management
    1. Levothyroxine indicated in symptomatic Hypothyroidism and chronic Hypothyroidism
  • Course
  1. Spontaneous resolution in most cases by 18 months after onset
  2. Persistent Hypothyroidism occurs in up to 15% of cases
    1. Requires longterm Thyroid replacment
  3. Recurrence in 2% of cases