Page 38 Complete Your CE Test Online - Click Here Riedel thyroiditis alert! Some experts believe that Riedel thyroiditis is not a disorder of the thyroid gland, but rather is a symptom of the systemic disorder multifocal fibrosclerosis. It is estimated that about 33% of Riedel thyroiditis cases are linked to findings of multifocal fibrosclerosis when diagnosed[21] . Riedel thyroiditis is usually self-limiting, and patients have a favorable prognosis. However, there are some potential complications of the disease including airway obstruction, dysphagia (difficult, painful swallowing), dysphonia (hoarseness), hypothyroidism, hypoparathyroidism, and stridor because of compression of the trachea by the thyroid gland[21] . Miscellaneous types of thyroiditis There are several other types of thyroiditis. These include[19] : ● ● Acute or infectious thyroiditis: This type of thyroiditis is usually due to a bacterial infection. Symptoms include sore throat, feeling generally sick, enlargement of the thyroid gland, and, occasionally, symptoms of hyperthyroidism or hypothyroidism. Symptoms usually resolve as the infection is treated with appropriate antibiotics. ● ● Drug-induced thyroiditis: Drug-induced thyroiditis is triggered by various drugs such as interferon (antiviral or immune response modifier), amiodarone (antiarrhythmic), and some anticancer drugs (e.g., sunitinib). Symptoms of hyperthyroidism or hypothyroidism may occur, but these usually resolve when drugs causing them are discontinued. ● ● Painless thyroiditis: The signs and symptoms of painless thyroiditis are similar to those of postpartum thyroiditis. However, painless thyroiditis can occur in both men and women and is not associated with childbirth. Painless thyroiditis usually causes a stage of high thyroid hormone levels, followed by a phase of low thyroid hormone levels, and, ultimately, a return to normal in about 12 to 18 months. ● ● Radiation induced thyroiditis: Radiation induced thyroiditis is triggered when radiation iodine treatment is used to treat overactive thyroid glands or for certain cancers. Resulting damage to the thyroid can cause symptoms of high or low levels of thyroid hormone. Hypothyroidism after treatment with radioactive iodine is usually permanent, and life-long thyroid hormone replacement therapy is needed. Nontoxic goiter Melanie is a 58-year-old partner in a prestigious law firm. After menopause, Melanie gained a bit of weight and has been rigidly dieting and vigorously exercising to maintain a trim figure. She has begun to notice some difficulty swallowing and a slight swelling in the front of her neck. Melanie dismisses these symptoms as annoying and continues with her busy lifestyle. During her annual physical exam her nurse practitioner notices the swelling and recommends some diagnostic laboratory tests. After reviewing the results of the tests and physical exam findings, Melanie is diagnosed with a “simple” goiter. Goiter is an abnormal enlargement of the thyroid gland. A simple, or nontoxic goiter is enlargement of the thyroid gland that is not due to inflammation or cancer and is not due to abnormal thyroid function [5,22] . Nontoxic goiter is most common in females, particularly during adolescence, pregnancy, and menopause. During these periods of a female’s life, the demand for thyroid hormone increases[11] . Goiter alert! Toxic goiter, as compared to nontoxic goiter, stems from long-standing nontoxic goiter and is found in elderly people. Toxic goiter manifests itself as an enlarged thyroid gland that develops small rounded masses and secretes excessive amounts of thyroid hormone [11] . Pathophysiology Nontoxic goiter occurs when the thyroid gland is unable to secrete sufficient thyroid hormone to meet the needs of the body. In an attempt to compensate for this insufficiency, the thyroid gland enlarges. Enlargement usually overcomes mild to moderate hormonal deficiencies[11] . Steps involved in the production of a nontoxic goiter are[5,11] : ● ● Impaired thyroid hormone synthesis and depletion of glandular organic iodine increase the thyroid glands response to normal levels of TSH. ● ● Increased response to normal TSH levels is accompanied by increases in thyroid gland mass and cellular activity, which compensate for mild deficiencies in the synthesis of thyroid hormone. Thus, metabolic function is normal even in the presence of a goiter. ● ● If an underlying disorder does exist or develop, and is severe, both a goiter and hypothyroidism may develop. Depending on the size of the goiter, dysphagia and even respiratory distress may develop[5] . Types of nontoxic goiter Nontoxic goiter is categorized as either endemic or sporadic. Endemic goiter affects more than 10% of a population[22] . Its development is usually due to a diet that is inadequate in iodine, which, in turn, leads to inadequate synthesis of thyroid hormone. In Japan, however, goiter due to excessive intake of seaweed-containing iodine has been identified[11] . In the United States, some geographic locations have actually been dubbed “goiter belts” since they have a high incidence of endemic goiter due to a lack of iodine in soil and water. These areas include the Midwest, Northwest, and Great Lakes region[11] . However, the introduction of iodized salt in the United States has drastically reduced the incidence of the disorder[5] . Sporadic goiter is the most common cause of goiter in the United States [22] . Sporadic goiter is usually the result of ingestion of large amounts of goitrogenic foods or drugs. Goitrogenic foods and drugs are those that contain substances that decrease the production of T4. Examples of such foods are cabbage, soybeans, peanuts, peaches, peas, strawberries, spinach, and radishes. Examples of drugs that decrease T4 production are propylthiouracil, iodides, lithium, cobalt, and aminosalicylic acid[11] . Experts believe that genetic defects may be responsible for inadequate T4 synthesis or damaged metabolism of iodine. However, because many families live in close geographic proximity inherited factors may contribute to the incidence of both endemic and sporadic goiters[5] . Diagnosis of nontoxic goiter Diagnosis is based on patient history and physical exam. It is important to rule out other disorders that can cause goiter and have similar effects but can range from mild to serious and even life-threatening such as thyroid carcinoma, Graves’ disease, and various types of thyroiditis[5] . Diagnostic alert! HCPs must always be alert to the influence of medications and diet on health. As in the cause of nontoxic goiter, foods and medications can be a major influence on its development [5,11] .