de Quervain’s Thyroiditis (Giant Cell Thyroiditis)

de Quervain’s thyroiditis is an autoimmune disease

Pathophysiology

1) inflammation and derangement of thyroid gland function 2) usually preceded by a viral illness (adenovirus, influenza) 3) marked by a hyperthyroid state for 2-3 months, followed by a period of hypothyroidism, followed by (usually) a recovery phase 4) occasionally accompanied by hemorrhage into the thyroid gland.

Signs and Symptoms

1) tremor 2) palpitations 3) nervousness 4) neck pain and tenderness 5) myalgias (muscle pain) 6) fatigue 7) sore throat 8) enlarged gland 9) malaise 10) jaw and ear pain

Characteristic Test Findings

Laboratory – 1) decreased serum TSH and increased T3 and T4 in hyperthyroid phase 2) increased serum TSH and decreased T3 and T4 in hypothyroid phase 3) increased erythrocyte sedimentation rate (ESR) 4) increased granulocyte count 5) increased IL-6 in hyperthyroid phase 6) increased antibody titers to adenovirus, mumps, and measles Nuclear Medicine – 7) low radioiodine uptake

Histology/Gross Pathology

1) patchy inflammatory infiltrate 2) some follicles with multinucleated giant cells and granulomas with fibrosis 3) thyroid eventually returns to normal if the disease resolves to a euthyroid state

Associated Conditions

associated with HLA-B35

Biochemistry

thyroid antibodies are negative

Inheritance/Epidemiology

1) true incidence is unknown 2) more common in women 3) peak age is 30-50 years

Treatment

1) NSAIDs and salicylates (aspirin) are first line treatment 2) 4-8 weeks of steroids if that fails 3) beta blockers for cardiac manifestations of thyrotoxicosis (palpitations and arrhythmias) 4) exogenous T3 and/or T4 during hypothyroid phase

Tips for USMLE

key concept is the four phases of the disease: viral illness, hyperthyroid phase, hypothyroid phase, return to euthyroid state