Subacute granulomatous thyroiditis

Subacute Granulomatous Thyroiditis

Subacute granulomatous thyroiditis, also known as de Quervain's thyroiditis, is a self-limiting inflammatory disorder of the thyroid gland. It is characterized by neck pain, fever, and a tender, enlarged thyroid. This condition is believed to be triggered by a viral infection and is more common in women than men.

Pathophysiology

Subacute granulomatous thyroiditis is thought to be caused by a viral infection that leads to an inflammatory response in the thyroid gland. The most commonly implicated viruses include the mumps virus, Coxsackie virus, and adenovirus. The inflammation results in the destruction of thyroid follicles, leading to the release of thyroid hormones into the bloodstream and causing transient hyperthyroidism.

Histologically, the thyroid gland shows granulomatous inflammation with multinucleated giant cells. This is a key feature that distinguishes it from other forms of thyroiditis.

Clinical Presentation

Patients with subacute granulomatous thyroiditis typically present with:

- Neck pain: Often radiating to the jaw or ears, and exacerbated by swallowing or turning the head. - Fever: Low-grade fever is common. - Thyroid tenderness: The thyroid gland is usually tender to palpation. - Transient hyperthyroidism: Symptoms such as palpitations, weight loss, and anxiety may occur due to the release of thyroid hormones.

Diagnosis

The diagnosis of subacute granulomatous thyroiditis is primarily clinical, supported by laboratory and imaging findings:

- Thyroid function tests: Initially show elevated free T4 and suppressed TSH levels, followed by a hypothyroid phase. - Erythrocyte sedimentation rate (ESR): Typically elevated, indicating inflammation. - Thyroid ultrasound: May show an enlarged thyroid with decreased echogenicity. - Radioactive iodine uptake (RAIU): Low uptake due to follicular destruction.

Treatment

The treatment of subacute granulomatous thyroiditis is mainly supportive:

- Nonsteroidal anti-inflammatory drugs (NSAIDs): Used to relieve pain and inflammation. - Corticosteroids: May be prescribed for severe cases to reduce inflammation. - Beta-blockers: Used to manage symptoms of hyperthyroidism.

Most patients recover completely within a few months, although some may experience a transient hypothyroid phase before returning to euthyroidism.

Prognosis

The prognosis for subacute granulomatous thyroiditis is excellent, with most patients recovering fully without long-term complications. Recurrence is rare.

Also see

- Thyroiditis - Hashimoto's thyroiditis - Graves' disease - Thyroid function tests

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