Acute thyroiditis of odontogenic origin.

If an abscess is not able to establish drainage through the skin surface or into the oral cavity, it may spread diffusely through fascial planes of the neck's soft tissue. Once the infection descends into the submandibular space, it may extend to the lateral pharyngeal space, and then to the retro-pharyngeal space. From here, it may reach the thyroid gland. The authors here describe a case of submandibular phlegmon derived from a periapical abscess of inferior premolar, which has reached the thyroid gland. The damage caused to the gland resulted in the release of a conspicuous quantity of thyroid hormones, thus causing a thyrotoxic pattern: temperature, cutaneous pallor, excessive perspiration, tremor, tiredness, weight loss, increased appetite, and tachycardia. Additionally, the gland's edema caused dysphagia and dysphonia commonly seen with thyroid gland enlargement. After dental drainage and appropriate anti-inflammatory and antibiotic therapy, administration of oral beta-blockers and corticosteroid therapy were performed to counteract thyrotoxicosis in order to prevent recurrences. Finally, a root canal was performed once the thyrotoxicosis had been resolved.