Acute Suppurative Thyroiditis Caused by Escherichia coli in an Immunocompetent Adult: A Case Report.

Acute Suppurative Thyroiditis (AST) is a very rare disorder of the thyroid gland, accounting for less than 1% of all thyroid diseases, owing to the protective mechanisms of the thyroid gland, including its rich vascular supply, extensive lymphatic drainage, well-developed capsule, and high iodine content. Gram-positive organisms are the most frequently reported etiological agents, while gram-negative pathogens such as Escherichia coli are rarely reported, particularly in immunocompetent individuals. We describe the case of a 54-year-old male who presented with a painful anterior neck swelling and dysphagia. Laboratory findings revealed leukocytosis, elevated inflammatory markers, and normal thyroid function. Imaging revealed a multiloculated abscess involving the right thyroid lobe and isthmus. Fine-needle aspiration yielded purulent material and culture-confirmed Escherichia coli. The patient was successfully managed with intravenous antibiotics and ultrasound-guided aspiration, with complete clinical resolution and no recurrence at follow-up. This case highlights the need to consider atypical pathogens even in immunocompetent individuals.