Acute suppurative thyroiditis
Acute suppurative (infectious) thyroiditis is a rare, painful bacterial infection of the thyroid gland, typically caused by Staphylococcus or Streptococcus species in an immunocompromised host, that can progress to abscess formation. Treatment is empiric intravenous antibiotics with source-control drainage of any abscess, since the normally iodine-rich, well-vascularized, encapsulated thyroid gland resists infection and a suppurative focus rarely resolves with antibiotics alone.
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What this article covers
- Overview
A rare bacterial infection of the thyroid gland: acute suppurative (infectious) thyroiditis is a painful thyroiditis caused by direct bacterial invasion of thyroid tissue, most often Staphylococcus or Streptococcus species.
- Epidemiology
A rare cause of thyroid disease overall: infectious (suppurative) thyroiditis is one of the least common causes of painful thyroiditis compared with the far more frequent subacute granulomatous thyroiditis.
- Risk factors
Immunocompromised status: the dominant risk factor, encompassing any condition or therapy that impairs host defense against bacterial invasion.
- Pathophysiology
Direct bacterial invasion of thyroid parenchyma: Staphylococcus or Streptococcus species establish infection within the gland, producing localized inflammation distinct from the diffuse follicular…
- Clinical features
Painful, tender thyroid swelling: the defining local finding, often unilateral or focal rather than the diffuse gland tenderness typical of subacute granulomatous thyroiditis.
- Differential diagnosis
Subacute granulomatous (de Quervain) thyroiditis: also produces a painful, tender gland, but follows a viral upper respiratory illness rather than bacterial infection and is not associated with frank…
- Diagnosis
The diagnosis is established, first, by recognizing a painful, tender, infected thyroid gland in a susceptible (often immunocompromised) host, then confirmed by fine-needle aspiration with Gram stain…
- Management
First, start empiric intravenous antibiotics targeting Staphylococcus and Streptococcus species while culture results are pending, continued until clinical improvement: ceftriaxone 2 g IV every 12…
- Complications
Progression to a mature thyroid abscess: the most direct local complication, requiring drainage in addition to antibiotics.
- Prognosis
Favorable with prompt antibiotics and drainage: outcomes are generally good when bacterial infection is identified early and treated with both antimicrobial therapy and source control.
- Prevention
Maintain a high index of suspicion for a painful thyroid in an immunocompromised patient, rather than defaulting to the diagnosis of subacute granulomatous thyroiditis, so that bacterial culture and imaging are obtained early.
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Related articles
- Subacute granulomatous thyroiditis
Subacute granulomatous (de Quervain) thyroiditis is a painful, tender destructive thyroiditis that follows a viral upper respiratory illness and produces a transient thyrotoxic phase, often followed by a hypothyroid phase, with a markedly elevated erythrocyte sedimentation rate. Treatment is symptomatic, an NSAID for mild pain or a glucocorticoid taper for moderate to severe pain, with a dramatic response within 24 to 48 hours, since thionamides and radioactive iodine have no role.
- Riedel thyroiditis
Riedel (fibrous) thyroiditis is a rare, IgG4-related fibrosclerosing process that replaces the thyroid gland with dense fibrous tissue, producing a fixed, stony-hard, painless goiter with compressive symptoms such as dyspnea, dysphagia, and hoarseness. First-line treatment is a corticosteroid to shrink the fibrotic mass and arrest progression, with tamoxifen or rituximab reserved for refractory disease and surgery limited to airway compromise.
- Hashimoto thyroiditis
Hashimoto thyroiditis is a chronic autoimmune process in which lymphocytic infiltration destroys the thyroid, and is the most common cause of hypothyroidism in iodine-sufficient regions such as the United States. Diagnosis rests on an elevated thyroid-stimulating hormone with a low or normal free thyroxine, and first-line treatment is lifelong levothyroxine replacement dosed to normalize thyroid-stimulating hormone.
- Thyroid nodules
A thyroid nodule is a discrete structural lesion within an otherwise normal thyroid gland, found on ultrasound in about 40% of the United States population though palpable in far fewer, and malignant in roughly 5%. Evaluation begins with a thyroid-stimulating hormone (TSH) level and thyroid ultrasonography, and management is surveillance for benign or low-risk nodules, with lobectomy or total thyroidectomy reserved for cytology suspicious for or diagnostic of malignancy.