In this short video, endocrinologist Tracy Tylee, MD will explain the basic pathophysiology of toxic thyroid nodules and how to diagnose them in your labs, ultrasound, and radio iodine scan. Enjoy!
If you like this video, make sure to check out our Thyroid Essentials course, where you'll become an expert of the thyroid gland!
[00:00:00] Another cause of hypothyroidism is autonomous or hyperfunctioning nodules. These are often suspected based on exam or on imaging findings. In this case, the thyroid has a nodule that is producing excess thyroid hormone. The thyroid hormone enters the bloodstream and acts at the level of the pituitary to decrease TSH. The labs will show an increase in thyroid hormone levels with a low TSH level. Thyroid nodules are more common in older people
[00:00:30] and more common in individuals who are from areas of iodine deficiency, which is Russia, parts of Europe, Africa, and Southeast Asia. Autonomous nodules tend to get worse over time. They grow bigger and tend to cause more symptoms. If you suspect an autonomous nodule based on exam, you should obtain an ultrasound, which will confirm the presence of a nodule but will not give you information about whether or not that nodule is hyperfunctioning. For that, you need to obtain a radioactive iodine scan. Autonomous nodules will appear as intense areas of focal
[00:01:00] uptake on the scan, consistent with a hot nodule. Non-functioning or cold nodules will show decreased uptake and occasionally, you'll have a thyroid with both hot nodules and cold nodules. But the radioactive iodine scan is the only way to definitively diagnose an autonomously functioning nodule.