Computed tomography of the thyroid ,88 and and9).9). CT scans are also the most sensitive diagnostic tool for the detection of pulmonary micro-metastases. Many of the neck US features that are considered as suggestive signs of disease recurrence are also applicable to CT examination. These signs might include sizable rounded nodules in the thyroid bed, fine calcifications, or cystic change. In cases of elevated thyroglobulin with negative neck US and iodine whole body scintigraphy (WBS), fluorodeoxyglucose (FDG) positron emission tomography (PET) is the next modality of choice. Dedifferentiated thyroid carcinoma usually has avid FDG-PET uptake and a negative radioiodine scan, typically does not respond to
Thyroid storm to sympathetic activation (see below). Sympathetic nervous system activation during times of stress may also play a significant role in thyroid storm. Sympathetic activation increases production of thyroid hormone by the thyroid gland. In the setting of elevated thyroid hormone, the density of thyroid hormone receptors (esp. beta-receptors) also increases, which enhances the response to catecholamines. This is likely responsible for several of the cardiovascular symptoms (increased cardiac output, heart rate, stroke volume) seen in thyroid storm. According to newer theories, thyroid storm results from allostatic failure in a situation where thyrotoxicosis hampers the development of non-thyroidal illness syndrome, which