Thyroid enlargement
Thyroid enlargement: Excerpt from Professional Guide to Signs & Symptoms (Fifth Edition)
An enlarged thyroid can result from inflammation, physiologic changes, iodine deficiency, and thyroid tumors. 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 include a family history of thyroid disease, when the thyroid enlargement began, 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 as well as the presence or absence of nodules. Using the bell of a stethoscope, listen over the lateral lobes for a bruit, which is commonly continuous.
Medical causes
Hypothyroidism
This disorder, which is most prevalent in women, usually results from a dysfunction of the thyroid gland caused by 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. A goiter that arises from a deficiency of iodine in the food or water of a particular area is 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; diaphoresis; 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 and substances in foods that decrease thyroxine production. Drugs containing goitrogens include lithium, sulfonamides, and para-aminosalicylic acid. 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 about 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-fiber, 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 therapy begins, watch for signs and symptoms of hyperthyroidism, such as restlessness, diaphoresis, 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.
Give patients with thyroiditis 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 in subacute thyroiditis. If the patient has severe hyperthyroidism (thyroid storm), closely monitor his 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, 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 talking, increased swallowing, or stridor. Keep tracheotomy equipment handy.
Pediatric pointers
Congenital goiter occurs in infantile myxedema (cretinism), a syndrome characterized by mental retardation, growth failure, and other signs and symptoms of hypothyroidism. Early treatment can prevent mental retardation. Advise the parents to obtain genetic counseling because their subsequent children are also at risk for this disorder.
Patient counseling
Instruct the patient to watch for signs and symptoms of hypothyroidism, such as lethargy, restlessness, dry skin, and sensitivity to cold. Advise the patient with Graves’disease to use artificial tears frequently if proptosis causes his eyes to become dry. If the hyperthyroid patient is receiving therapy with radioactive iodine, tell him not to expectorate or cough freely after treatment because his saliva is radioactive for 24 hours.
Inform the patient that lifelong thyroid hormone replacement therapy is necessary after thyroidectomy or radioactive destruction of the thyroid gland. Tell him to watch for signs of an overdose, such as nervousness and palpitations.
Book Source Details
- Book Title: Professional Guide to Signs & Symptoms (Fifth Edition)
- Author(s): Springhouse
- Year of Publication: 2006
- Copyright Details: Professional Guide to Signs & Symptoms (Fifth Edition), Copyright © 2006 Lippincott Williams & Wilkins.
More About Hashimoto's Thyroiditis
More Medical Textbooks Online about Hashimoto's Thyroiditis
Review other book chapters online related to Hashimoto's Thyroiditis:
Medical Books Excerpts
- Thyroiditis
- "Professional Guide to Diseases (Eighth Edition)" (2005)
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- Thyroid Nodule
- "The 10-Minute Diagnosis Manual: Symptoms and Signs in the Time-Limited Encounter" (2000)
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- Goiter
- "The 5-Minute Pediatric Consult" (2008)
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Copyright notice for book excerpts: Copyright © 2008 Lippincott Williams & Wilkins. All rights reserved.
» Next page: Exophthalmos [Proptosis] (Professional Guide to Signs & Symptoms (Fifth Edition))
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