Thyroid nodules are quite common, especially those smaller than one centimeter. Most of these nodules do not cause any symptoms, so many people are not aware of them.

The thyroid gland is filled with tiny blood vessels. When the small blood vessels on the surface of a nodule start bleeding, blood can accumulate within the nodule, causing it to suddenly enlarge and become painful. This condition is known as a hemorrhagic cyst of thyroid, and patients may experience sudden pain and swelling in the thyroid area. In most cases, hemorrhagic nodules tend to decrease in size within three to four weeks.

After a clinical examination, doctors generally recommend thyroid ultrasound to differentiate thyroid nodules, cysts, or other conditions such as thyroid cancer. Additionally, doctors can use ultrasound guidance for fine-needle aspiration of thyroid cysts. This procedure involves extracting cells from the cyst for pathological analysis, which helps determine the nature of the thyroid cells.

After confirmation of diagnosis, most cases of haemorrhagic cysts can be managed through observation. Typically, these cysts will significantly decrease in size within three to four weeks. However, if a patient experiences severe swelling and pain in the thyroid, the doctor may perform a fine-needle aspiration to extract the accumulated blood within the cyst. Non-steroidal anti-inflammatory drugs (NSAIDs) may be prescribed to alleviate symptoms.

Furthermore, regular thyroid ultrasound examinations every six to twelve months can monitor any abnormal changes in the thyroid cyst. If there are significant size or imaging changes detected during the ultrasound examination, the doctor may arrange for another ultrasound-guided fine-needle aspiration to extract cells for further analysis.