00:01 Let's go on to another case. 00:03 A 55 year old woman was diagnosed with hyperthyroidism one week ago. 00:07 She also has a palpable right thyroid nodule which was found on clinical exam. 00:12 Her TSH was low and her free T4 was elevated. 00:17 She has no weight loss, no history of prior malignancy nor family history of any cancer. 00:23 What is the best next step in managing this patient? So clinically based on the information that we have, she has been diagnosed with hyperthyroidism and she also has a palpable right thyroid nodule. 00:37 This points to the diagnosis of a toxic adenoma. 00:41 The next step in the management would be thyroid scintigraphy scan or radioactive iodine uptake which in this case would show a single area of increased uptake of iodine in the area of the toxic adenoma. 00:58 Thyroid scintigraphy scanning is a nuclear medicine procedure that produces a visual display of functional thyroid tissue based on the selective uptake of radioactive iodine nucleides by the thyroid tissue. 01:13 If you look at this image, you see areas on the gray background of intense uptake which are much, much darker representing large black dots. 01:22 These represent toxic adenomas within the thyroid gland and are very discreet. 01:30 Activating mutations in the TSH receptor gene stimulate the production of thyroid hormone in a toxic nodule, usually referred to as an adenoma. 01:40 or in multiple hyperfunctioning nodules in a toxic multinodular goiter. 01:46 On exam, the nodule may be palpable or diffusely enlarged where it's called a goiter or it may have a nodular contour. 01:55 There is a very low risk of autonomous nodules from malignant transformation. 02:01 Usually in the range of less than 1%. 02:04 The diagnosis is usually made by thyroid scintigraphy. 02:07 In the case of an autonomous toxic nodule, this is described as "hot" or very dark on imaging. 02:17 You should always correlate any nodules found on scintigraphy scanning with an associated ultrasound. 02:23 Any additional nodules that are found on ultrasound that are not seen on scintigraphy scanning may require further investigation by doing a fine needle aspiration. 02:35 Radioactive iodine ablation emits gamma and beta radiation. 02:40 The camera detecting this on a nuclear testing will detect the uptake of the thyroid hormone and generate a picture for diagnosis. 02:51 Indications for surgery in patients with toxic adenomas include very large goiters with compression symptoms on the underlying tissue where there is concern for malignancy. 03:02 TSH secreting pituitary adenomas are extremely rare. 03:06 These are causes of secondary or central hyperthyroidism. 03:10 Serum TSH is detectable or normal with elevated T4 and/or T3 levels. 03:17 A pituitary MRI in these cases will usually demonstrate an adenoma. 03:21 The treatment for these conditions is removal of the pituitary tumor as thyroid-targeted therapy is invariably ineffective.
The lecture Toxic Adenoma and Multinodular Goiter with Case by Michael Lazarus, MD is from the course Thyroid Disorders. It contains the following chapters:
What is the management for a TSH-secreting pituitary adenoma?
What should the initial treatment be for a 'hot' nodule?
What is the next step in treating the patient described below? Hyperthyroidism was diagnosed in a 55-year-old woman 1 week ago when a palpable right thyroid nodule was found on exam. She has no weight loss, no history of prior malignancy, and no family history of cancer. Lab test results: low TSH, elevated free T4
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excellent, good images and clearly explained. Thank you for a good lecture.
Thank you, Dr. Your lecture was simple and easy to understand.