Underactive thyroid (hypothyroidism) is a well-known condition; in contrast, overactive thyroid (hyperthyroidism) is a less appreciated but still important endocrine problem.
Recent reports found that mild or subclinical hyperthyroidism, in which the thyroid hormones, T4 and T3 are normal, but the pituitary hormone, TSH, is suppressed, may cause symptoms including fatigue, nervousness, anxiety, shortness of breath, palpitations, trouble sleeping, increased appetite, loose stool or diarrhea, tremors and weight loss, although rarely, weight gain occurs. Many patients with mild hyperthyroidism may have only a few of these symptoms. Most of these symptoms will worsen without treatment, and the patient may suffer osteoporosis (thinning of the bones) or heart disease. With proper diagnose and treatment, however, symptoms improve. Therefore, one should see an endocrinologist with expertise in thyroid disorders if you could have hyperthyroidism.
Diagnosis of hyperthyroidism and determination of the type of hyperthyroidism
There are many causes of hyperthyroidism, and proper treatment requires both a diagnosis (usually done with history and laboratory tests) and a determination of the type of hyperthyroidism (usually done with history, thyroid examination and nuclear medicine tests). To diagnose hyperthyroidism, Dr. Friedman will measure TSH, free T4 and free T3. A suppressed TSH with an elevated free T4 and free T3 indicates frank hyperthyroidism, while a suppressed TSH with an upper-normal free T4 and free T3 indicates subclinical hyperthyroidism. A suppressed TSH with a low or low-normal free T4 and free T3
indicates hypothyroidism due to a pituitary problem. An elevated TSH indicates hypothyroidism due to a thyroid problem.
Once Dr. Friedman determines that a patient has hyperthyroidism, he then determines which type of hyperthyroidism the patient has. The four common causes of hyperthyroidism are: Graves' (the most common); toxic multinodular goiter; single hot nodule (Plummer’s disease); and subacute thyroiditis.