Acute thyroiditis is primarily caused by which type of pathogen?

Acute thyroiditis is primarily caused by bacterial agents, which is why this answer is considered correct. Bacterial infections can lead to acute inflammation of the thyroid gland, often as a result of an infection that spreads to the thyroid from adjacent structures or through the bloodstream.

In many cases, the common bacteria involved in acute thyroiditis may include organisms such as Staphylococcus aureus or Streptococcus species. This type of thyroiditis is characterized by sudden onset of pain and swelling in the neck, fever, and dysphagia, which are indicative of an infectious process.

While viral infections can also affect the thyroid, leading to a condition known as subacute (or de Quervain's) thyroiditis, they typically present differently and are not the primary cause of acute thyroiditis. Autoimmune responses, like Hashimoto's thyroiditis, are chronic conditions and not responsible for acute presentations. Fungal infections are rare and typically do not cause acute thyroiditis, making them an unlikely primary pathogen in this context.