Despite all this, a persistent fistula from the piriform sinus may make the left lobe of the thyroid susceptible to infection and abscess formation.

In most cases AIT is characterized by onset of pain, firmness, tenderness, redness or swelling in the anterior aspect of the neck.

[4] Pain, fever and swelling are often much more severe and continue to get worse in people who have AIT compared to those with other thyroid conditions.

One study found that of the reported cases of AIT, 66% occurred after an acute illness involving the upper respiratory tract.

Patients who are suspected of having AIT often undergo tests to detect for elevated levels of white blood cells as well as an ultrasound to reveal unilobular swelling.

[1][4] Depending on the age and immune status of the patient more invasive procedures may be performed such as fine needle aspiration of the neck mass to facilitate a diagnosis.

Based on the offending organism found on microscopic examination of the stained fine needle aspirate, the appropriate antibiotic treatment is determined.

[2] Empirical broad spectrum antimicrobial treatment provides preliminary coverage for a variety of bacteria, including S. aureus and S. pyogenes.

Certain Gram-negative bacilli (ex: Prevotella, Fusobacteriota, and Porphyromonas) are exhibiting an increased resistance based on the production of beta-lactamase.

[4] The draining procedure is also based on clinical examination or ultrasound/CT scan results that indicate an abscess or gas formation.