Thyroid cancer
Thyroid cancer occurs in all age groups, especially in persons who have had radiation treatment to the neck area. Papillary and follicular carcinomas are most common and are usually associated with prolonged survival.
Papillary carcinoma accounts for half of all thyroid cancers in adults; it’s most common in young adult females and metastasizes slowly. It’s the least virulent form of thyroid cancer. Follicular carcinoma is less common but more likely to recur and metastasize to the regional nodes and through blood vessels into the bones, liver, and lungs.
Medullary carcinoma originates in the parafollicular cells derived from the last branchial pouch and contains amyloid and calcium deposits. It can produce calcitonin, histaminase, corticotropin (producing Cushing’s syndrome), and prostaglandin E2 and F3 (producing diarrhea).
This rare form of thyroid cancer is familial, associated with pheochromocytoma, and completely curable when detected before it causes symptoms. Untreated, it progresses rapidly.
Seldom curable by resection, giant and spindle cell cancer (anaplastic tumor) resists radiation and metastasizes rapidly.
Causes
Predisposing factors include radiation exposure, prolonged thyrotropin stimulation (through radiation or heredity), familial predisposition, or chronic goiter.
Signs and symptoms
The primary signs of thyroid cancer are a painless nodule, a hard nodule in an enlarged thyroid gland, or palpable lymph nodes with thyroid enlargement. Eventually, the pressure of such a nodule or enlargement causes hoarseness, dysphagia, dyspnea, and pain on palpation.
If the tumor is large enough to destroy the gland, hypothyroidism follows, with its typical symptoms of low metabolism (mental apathy and sensitivity to cold). However, if the tumor stimulates excess thyroid hormone production, it induces symptoms of thyrotoxicosis (sensitivity to heat, restlessness, and hyperactivity).
Other clinical features include diarrhea, anorexia, irritability, vocal cord paralysis, and symptoms of distant metastasis.
Diagnosis
The first clue to thyroid cancer is usually an enlarged, palpable node in the thyroid gland, neck, lymph nodes of the neck, or vocal cords. A patient history of radiation therapy or a family history of thyroid cancer supports the diagnosis. However, tests must rule out nonmalignant thyroid enlargements, which are more common.
❑ Fine needle biopsy detects cancer cells.
❑ Thyroid scan differentiates between functional nodes (rarely malignant) and hypofunctional nodes (commonly malignant) by measuring how readily nodules trap isotopes compared with the rest of the thyroid gland. In thyroid cancer, the scintiscan shows a “cold,” nonfunctioning nodule.
❑ Other tests include computed tomography scan, ultrasonic scan, and serum calcitonin assay to diagnose medullary cancer. Calcitonin assay is a reliable clue to silent medullary carcinoma.
Treatment
❑ Total or subtotal thyroidectomy, with modified node dissection (bilateral or unilateral) on the side of the primary cancer (papillary or follicular cancer)
❑ Total thyroidectomy and radical neck excision (for medullary, giant, or spindle cell cancer)
❑ Radiation (with or without surgery)
❑ Adjunctive thyroid suppression, with exogenous thyroid hormones suppressing thyrotropin production, and simultaneous administration of an adrenergic blocking agent such as propranolol, increasing tolerance to surgery and radiation
❑ Chemotherapy for symptomatic, widespread metastasis is limited, but doxorubicin is sometimes beneficial.
UNDER STUDY: Researchers are excited about recent advancements in the treatment of thyroid cancer:
❑ Researchers have identified the genetic cause of medullary thyroid carcinoma, which makes it possible to identify carriers of the abnormal gene.
❑ Improvements in imaging studies have proven helpful in the treatment of patients who present with clinically challenging conditions such as the presence of antithyroglobulin antibodies.
❑ New treatments such as the use of agents to improve iodine uptake in follicular cell tumors are in early investigation.
Special considerations
❑ Before surgery, tell the patient to expect temporary voice loss or hoarseness lasting several days after surgery.
Postoperative care:
❑ When the patient regains consciousness, keep him in semi-Fowler’s position, with his head neither hyperextended nor flexed, to avoid pressure on the suture line. Support the patient’s head and neck with sandbags and pillows; when you move him, continue this support with your hands.
❑ After monitoring vital signs, check the patient’s dressing, neck, and back for bleeding. If he complains that the dressing feels tight, loosen it.
❑ Check serum calcium levels daily; hypocalcemia may develop if parathyroid glands are removed.
❑ Watch for and report other complications: hemorrhage and shock (elevated pulse rate and hypotension), tetany (carpopedal spasm, twitching, and seizures), thyroid storm (high fever, severe tachycardia, delirium, dehydration, and extreme irritability), and respiratory obstruction (dyspnea, crowing respirations, and retraction of neck tissues).
❑ Keep a tracheotomy set and oxygen equipment handy in case of respiratory obstruction. Use continuous steam inhalation in the patient’s room until his chest is clear.
❑ The patient may need I.V. fluids or a soft diet, but many patients can tolerate a regular diet within 24 hours of surgery.
Book Source Details
- Book Title: Handbook of Diseases
- Author(s): Springhouse
- Year of Publication: 2003
- Copyright Details: Handbook of Diseases, Copyright © 2003 Lippincott Williams & Wilkins.
Other Book Chapters Related to Thyroid symptoms
Read excerpts from these other book chapters related to Thyroid symptoms:
Medical Books Excerpts
- Thyroiditis
- "Professional Guide to Diseases (Eighth Edition)" (2005)
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- Weight Loss
- "The 10-Minute Diagnosis Manual: Symptoms and Signs in the Time-Limited Encounter" (2000)
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- Thyroid Nodule
- "The 10-Minute Diagnosis Manual: Symptoms and Signs in the Time-Limited Encounter" (2000)
- [ read ]
Copyright Details: Handbook of Diseases, Copyright © 2008 Williams & Wilkins.
More About Causes of Thyroid symptoms
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More About This Book:
Title: Handbook of Diseases
Authors: Springhouse
Publisher: Lippincott Williams & Wilkins
Copyright: 2003
ISBN: 1-58255-266-5
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» Next page: Thyroiditis (Handbook of Diseases)
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