Thyroid enlargement
Thyroid enlargement: Excerpt from Handbook of Signs & Symptoms (Third Edition)
An enlarged thyroid can result from inflammation, physiologic changes, iodine deficiency, thyroid tumors, and drugs. Depending on the medical cause, hyperfunction or hypofunction may occur with resulting excess or deficiency, respectively, of the hormone thyroxine. If no infection is present, enlargement
is usually slow and progressive. An enlarged thyroid that causes visible swelling in the front of the neck is called a goiter.
History and physical examination
The patient’s history commonly reveals the cause of thyroid enlargement. Important data includes a family history of thyroid disease, onset of thyroid enlargement, any previous irradiation of the thyroid or the neck, recent infections, and the use of thyroid replacement drugs.
Begin the physical examination by inspecting the patient’s trachea for midline deviation. Although you can usually see the enlarged gland, you should always palpate it. To palpate the thyroid gland, you’ll need to stand behind the patient. Give the patient a cup of water, and have him extend his neck slightly. Place the fingers of both hands on the patient’s neck, just below the cricoid cartilage and just lateral to the trachea. Tell the patient to take a sip of water and swallow. The thyroid gland should rise as he swallows. Use your fingers to palpate laterally and downward to feel the whole thyroid gland. Palpate over the midline to feel the isthmus of the thyroid.
During palpation, be sure to note the size, shape, and consistency of the gland, and the presence or absence of nodules. Using the bell of a stethoscope, listen over the lateral lobes for a bruit. The bruit is often continuous.
Medical causes
Hypothyroidism
Hypothyroidism is most prevalent in women and usually results from a dysfunction of the thyroid gland, which may be due to surgery, irradiation therapy, chronic autoimmune thyroiditis (Hashimoto’s disease), or inflammatory conditions, such as amyloidosis and sarcoidosis. Besides an enlarged thyroid, signs and symptoms include weight gain despite anorexia; fatigue; cold intolerance; constipation; menorrhagia; slowed intellectual and motor activity; dry, pale, cool skin; dry, sparse hair; and thick, brittle nails. Eventually, the face assumes a dull expression with periorbital edema.
Iodine deficiency
A goiter may result from a lack of iodine in the diet. If the goiter arises from a deficiency of iodine in the food or water of a particular area, it’s called an endemic goiter. Associated signs and symptoms of an endemic goiter include dysphagia, dyspnea, and tracheal deviation. This condition is uncommon in developed countries with iodized salt.
Thyroiditis
Thyroiditis, an inflammation of the thyroid gland, may be classified as acute or subacute. It may be due to bacterial or viral infections, in which case associated features include fever and thyroid tenderness. The most prevalent cause of spontaneous hypothyroidism, however, is an autoimmune reaction, as occurs in Hashimoto’s thyroiditis. Autoimmune thyroiditis usually produces no symptoms other than thyroid enlargement.
Thyrotoxicosis
Overproduction of thyroid hormone causes thyrotoxicosis. The most common form is Graves’disease, which may result from genetic or immunologic factors. Associated signs and symptoms include nervousness; heat intolerance; fatigue; weight loss despite increased appetite; diarrhea; sweating; palpitations; tremors; smooth, warm, flushed skin; fine, soft hair; exophthalmos; nausea and vomiting due to increased GI motility and peristalsis; and, in females, oligomenorrhea or amenorrhea.
Tumors
An enlarged thyroid may result from a malignant tumor or a nonmalignant tumor (such as an adenoma). A malignant tumor usually appears as a single nodule in the neck; a nonmalignant tumor may appear as multiple nodules in the neck. Associated signs and symptoms include hoarseness, loss of voice, and dysphagia.
Thyroid tissue contained in ovarian dermoid tumors can function autonomously or in combination with thyrotoxicosis. Pituitary tumors that secrete thyroid-stimulating hormone (TSH), a rare type, are the only cause of normal or high TSH levels in association with thyrotoxicosis. Finally, high levels of human chorionic gonadotropin, as seen in trophoblastic tumors and pregnant women, can cause thyrotoxicosis.
Other causes
Goitrogens
Goitrogens are drugs — such as lithium, sulfonamides, phenylbutazone, and para-aminosalicylic acid — and substances in foods that decrease thyroxine production. Foods containing goitrogens include peanuts, cabbage, soybeans, strawberries, spinach, rutabagas, and radishes.
Special considerations
Prepare the patient with an enlarged thyroid for scheduled tests, which may include needle aspiration, ultrasound, and radioactive thyroid scanning. Also prepare him for surgery or radiation therapy, if necessary. If the patient has a goiter, support him as he expresses his feelings related to his appearance.
The hypothyroid patient will need a warm room and moisturizing lotion for his skin. A gentle laxative and stool softener may help with constipation. Provide a high-bulk, low-calorie diet, and encourage activity to promote weight loss. Warn the patient to report any infection immediately; if he develops a fever, monitor his temperature until it’s stable. After thyroid replacement begins, watch for signs and symptoms of hyperthyroidism, such as restlessness, sweating, and excessive weight loss. Avoid administering a sedative, if possible, or reduce the dosage because hypothyroidism delays metabolism of many drugs. Check arterial blood gas levels for indications of hypoxia and respiratory acidosis to determine whether the patient needs ventilatory assistance.
For patients with thyroiditis, give an antibiotic and watch for elevations in temperature, which may indicate developing resistance to the antibiotic. Check vital signs, and examine the patient’s neck for unusual swelling or redness. Provide a liquid diet if the patient has difficulty swallowing. Check for signs of hyperthyroidism, such as nervousness, tremor, and weakness, which are common with subacute thyroiditis. The patient with severe hyperthyroidism (thyroid storm) will need close monitoring of temperature, volume status, heart rate, and blood pressure.
After thyroidectomy, check vital signs every 15 to 30 minutes until the patient’s condition stabilizes. Be alert for signs of tetany secondary to parathyroid injury during surgery. Monitor postoperative serum calcium levels, monitor the patient for a positive Chvostek and Trousseau signs, and keep 10% calcium gluconate available for I.V. use as needed. Evaluate dressings frequently for excessive bleeding, and watch for signs of airway obstruction, such as difficulty in talking, increased swallowing, or stridor. Keep tracheotomy equipment handy.
Pediatric pointers
Congenital goiter, a syndrome of infantile myxedema or cretinism, is characterized by mental retardation, growth failure, and other signs and symptoms of hypothyroidism. Early treatment can prevent mental retardation. Genetic counseling is important, as subsequent children are at risk.
Book Source Details
- Book Title: Handbook of Signs & Symptoms (Third Edition)
- Author(s): Springhouse
- Year of Publication: 2006
- Copyright Details: Handbook of Signs & Symptoms (Third Edition), Copyright © 2006 Lippincott Williams & Wilkins.
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Copyright notice for book excerpts: Copyright © 2008 Lippincott Williams & Wilkins. All rights reserved.
» Next page: Hyperparathyroidism (Professional Guide to Diseases (Eighth Edition))
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