Subacute Thyroiditis

Refers to a transient patchy inflammation of the thyroid

De Quervain's thyroiditis

  • Describes the presentation of a viral infection with fever, neck pain and tenderness, dysphagia and features of hyperthyroidism

Aetiology

  • Ages 20-50
  • May be triggered by viral infection

Clinical presentation

  • Painful, diffuse, firm goitre
  • Fever and/or malaise may be present
  • There is a hyperthyroid phase followed by a hypothyroid phase as the TSH level falls due to negative feedback

Investigations

  • Thyroid function tests
  • May perform scintigraphy scan to rule out other causes of hyperthyroidism, will be low uptake throughout
  • FNAB → multinucleated giant cells

Management

  • Self-limiting condition - supportive treatment with NSAIDs for pain and inflammation and beta-blockers for symptomatic relief of hyperthyroidism is usually all that is necessary
    • Aspirin 600 mg/6-8 hr
    • Glucocorticoid → Prednisone 40-60 mg/day then tappering off in 6-8 weeks
    • If tyhrotoxicosis, give propanolol to relieve symptoms
    • If hypothyroid, give levothyroxine 50-100 mcg/day

Post-partum thyroiditis

  • See 'Thyroid Disease and Pregnancy' notes

Drug-induced thyroiditis

Aetiology

  • Drugs which can induce thyroiditis include amiodarone and lithium
  • Amiodarone inhibits DIO1 - increased free T4, decreased free T3, normal TSH
    • Hypothyroidism occurs in 13% - tends to occur in iodine rich areas
    • Hyperthyroidism occurs in 2% - tends to occur in iodine deficient areas, split into type 1 (similar to Graves', type 2 (destructive thyroiditis) or mixed

Management

  • Resolves without treatment in many cases
  • Steroid therapy may be necessary with some drugs

Others

  • Radiation
  • Acute suppurative thyroiditis - bacterial