Hyperthyroidism
How is it treated?
The goals of treatment for hyperthyroidism include the elimination of excess thyroid hormone production, the relief of symptoms, and the prevention of becoming hypothyroid after treatment.
In cases where the thyroid is producing too much thyroid hormone, drugs can be given that block the hormone's formation or its conversion to a more active form. This drug class is called thionamides and includes two drugs, methimazole and propylthiouracil. They are indicated in Graves' disease to induce remission and usually cause a decrease in hormone levels and symptoms within 4-8 weeks. Dose changes are likely necessary over this beginning period but should be able to be tapered down as thyroid function normalizes. Therapy usually lasts for 1-2 years with an average remission rate of almost 50%. If relapse occurs, radioactive iodine is an alternate therapy.
Iodides are used in combination with surgery as a means to rapidly acquire a euthyroid state (normal thyroid function or normal levels of TSH,) or with radioactive iodine (see below) to prevent thyroid hormone release. Iodides block thyroid hormone release, inhibit the hormone's formation, and decrease the size of the thyroid gland.
Beta blockers are often given to help control symptoms such as palpitations, increased heart rate, sweating, and anxiety. They do not affect the level of thyroid hormone in the blood but act on the heart within hours to provide relief. They may cause fatigue, nausea, or light headedness, but are usually well-tolerated if started at a lower dose and slowly increased. In most cases, unless the physician and patient carefully monitors, beta blockers should not be used by those with asthma, heart failure, COPD, or a resting heart rate below 60. An alternative to control the heart rate and these symptoms is diltiazem.
Radioactive Iodine is the agent of choice to treat Graves' disease, toxic adenoma, and multinodular goiters. It is a liquid that concentrates in the thyroid gland and causes ablation (destruction of the cells.) This therapy commonly causes hypothyroidism which results in the need for thyroid hormone supplementation.
Thyroid removal is uncommonly performed in the United States. If surgery is elected for a patient with a toxic nodule, the surgeon removes the part of the thyroid which is dysfunctional and the thyroid remnant usually resumes normal function. However, if the entire thyroid is over productive, as in Graves' disease, the surgeon must remove most or the entire gland. In such cases, the patient must then take thyroid hormone replacement pills for the rest of his or her life. Candidates for surgery may include pregnant hyperthyroid patients intolerant of antithyroid drugs, patients desiring definitive therapy without the use of radioactive iodine, children, and patients with very large or nodular goiters.
Thyroid storm, also called thyrotoxic crisis, is a life threatening medical emergency where a hyperthyroid patient enters a high metabolic state. It is a rare condition, more likely in adolescents and females, but extremely fatal (mortality rate > 50%) if untreated. Presentation is that of an extreme level of thyroid hormones and includes fever, fast heart rate, delirium, nausea, vomiting, diarrhea, high blood pressure. Untreated thyroid storm progresses to heart failure, low blood pressure with shock, arrhythmias, seizures, and coma.
Factors that can cause thyroid storm are infection, surgery, trauma, treatment with radioactive iodine, pregnancy, and an overdose of thyroid hormone. Treatment is aimed at suppressing thyroid function, usually with high doses of propylthiouracil. Steroids, beta blockers and supportive therapy to correct fluids and prevent arrhythmias are often given.
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How is it treated?
