Other Assays Rarely Used- General availability of assays that can reliably measure suppressed TSH has made this the gold standard to which other tests must be compared, and has effectively eliminated the need for most previously used ancillary tests. There are only rare causes of confusion in the TSH assay. Severe illness, dopamine and steroids, and hypopituitarism, can cause low TSH, but suppression below µ/ml is uncommon and below µ/ml is exceptional, except in thyrotoxicosis. Thyrotoxicosis is associated with normal or high TSH in patients with TSH producing pituitary tumors and selective pituitary resistance to thyroid hormone.
If TSH, FT4, TRAb, and other tests noted above do not establish the diagnosis, it may be wise to do nothing further except to observe the course of events. In patients with significant thyroid hyperfunction, the symptoms and signs will become clearer, and the laboratory measurements will fall into line. Measurement of BMR, T3 suppression of RAIU, TRH testing, and clinical response to KI are of historical interest.
Thyroid storm requires emergent treatment and hospitalization. The main treatment is to decrease the circulating thyroid hormone levels and decrease their formation. Moreover, the high fever and possible dehydration is treated emergently with cooling of the body and IV hydration. PTU and methimazole are two agents that decrease thyroid hormone synthesis and are usually prescribed in fairly high doses. To inhibit thyroid hormone release from the thyroid gland, sodium iodide, potassium iodide and/or Lugol's solution can be given. Beta blockers such as propranolol ( Inderal , Inderal LA ) can help to control the heart rate, and intravenous steroids may be used to help support the circulation.