Thyrotoxicosis means that there is too much thyroid hormone in the blood, and the thyroid is overactive. This is also known as hyperthyroidism. Teritary means that it is a result of another problem, such as the pituitary gland not functioning properly. Secondary hyperthyroidism, is caused by the pituitary secreting too much Thyroid Stiumlating Hormone, in turn causing the thyroid to overproduce hormones. Treatment of the underlying problem is key to getting the thyroid to function properly. Thyrotoxicosis is also a term to describe thyroid storm, a serious medical emergency where there is a dangerous amount of thyroid hormone in the blood causing cardiac complications. Teritary thyrotoxicosis is a thyroid problem caused by another underlying condition causing the thyroid to become overactive. This is not as common as primary hyperthyroidism.