Subacute (de Quervain) Thyroiditis
A 34-year-old woman has 10 days of fever and anterior neck pain that began two weeks after an upper respiratory tract infection. The thyroid is diffusely enlarged and exquisitely tender to light palpation, with no eye signs. TSH is 9.8 mIU/L, free T4 is low, anti-thyroid peroxidase antibody is 10 IU/mL, erythrocyte sedimentation rate 78 mm/h and C-reactive protein 62 mg/L. What is the most likely diagnosis?
- A.Graves disease
- B.Hashimoto thyroiditis
- C.Sick euthyroid syndrome
- D.Subacute granulomatous thyroiditisCorrect
Explanation
A painful, tender goitre following a viral upper respiratory illness, with a markedly raised erythrocyte sedimentation rate and negative thyroid autoantibodies, is subacute granulomatous (de Quervain) thyroiditis. The illness is a post-viral inflammatory destruction of follicles that follows a characteristic triphasic course: an initial thyrotoxic phase of 2 to 8 weeks from release of preformed hormone (with a suppressed TSH and low radioiodine uptake), then a hypothyroid phase such as this woman is now in, with a raised TSH and low free T4, and finally recovery to euthyroidism in about 90% of patients. Radioiodine uptake is low, which distinguishes it from Graves disease where uptake is diffusely high. Management is symptomatic: nonsteroidal anti-inflammatory drugs for mild disease, prednisolone for severe pain, and a beta-blocker for adrenergic symptoms during the thyrotoxic phase; antithyroid drugs are useless because there is no excess hormone synthesis, and thyroxine is used only if the hypothyroid phase is prolonged and symptomatic. Hashimoto thyroiditis is the commonest cause of hypothyroidism with a goitre but is painless and is defined by high anti-thyroid peroxidase antibodies, which are normal here. Sick euthyroid syndrome occurs in severe systemic illness and typically shows a low T3 with a normal or low TSH, not a raised TSH with a painful goitre. Graves disease causes a low TSH with a high free T4, a painless diffuse goitre with a bruit, ophthalmopathy, and TSH receptor stimulating antibodies.
Why each option
- A.
- Graves disease produces a suppressed TSH, high free T4, painless goitre and eye signs with high radioiodine uptake.
- B.
- Hashimoto thyroiditis causes a painless goitre with markedly raised anti-thyroid peroxidase antibodies, which are normal in this patient.
- C.
- Sick euthyroid syndrome arises in severe systemic illness with a low T3 and non-elevated TSH, and does not cause thyroid pain.
- D.
- Correct. Post-viral painful tender goitre with a very high ESR, negative anti-TPO and a hypothyroid phase is classic de Quervain thyroiditis.
Reference: ATA Guidelines for Diagnosis and Management of Thyrotoxicosis, 2016; UpToDate 2025, Subacute thyroiditis
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