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Other Considerations. Differential Diagnoses. Nodular Non-toxic Goiter Graves’ Disease Toxic Multinodular Goiter Toxic Adenoma Solitary Thyroid Nodule. Nodular Non-toxic Goiter. Enlargement of the thyroid gland No toxicity; no cancer
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Differential Diagnoses • Nodular Non-toxic Goiter • Graves’ Disease • Toxic MultinodularGoiter • Toxic Adenoma • Solitary Thyroid Nodule
Enlargement of the thyroid gland • No toxicity; no cancer • The following factors increase your chance of developing nontoxic goiter: • Sex: female (nontoxic goiter is more common in women than men) • Age: over 40 years Reference: http://www.mbmc.org/healthgate/GetHGContent.aspx
SYMPTOMS • Nontoxic goiters usually do not have noticeable symptoms. • Swelling on the neck • Breathing difficulties, coughing, or wheezing with large goiter • Difficulty swallowing with large goiter • Feeling of pressure on the neck • Hoarseness
MANAGEMENT • A goiter only needs to be treated if it is causing symptoms. • Treatments for an enlarged thyroid include: • Radioactive iodine to shrink the gland, particularly if the thyroid is producing too much thyroid hormone • Surgery (thyroidectomy) to remove all or part of the gland • Small doses of Lugol's iodine or potassium iodine solution if the goiter is due to iodine deficiency • Treatment with thyroid hormone supplements if the goiter is due to underactive thyroid Reference: http://www.nlm.nih.gov/medlineplus/ency/article/001178.htm
INDICATIONS FOR SURGERY • Huge goiter which is cosmetically unacceptable • Compression symptoms • Suspicion of malignancy
GRAVES’ DISEASE • Atype of hyperthyroidism, is caused by a generalized overactivity of the entire thyroid gland. • An autoimmune disease; thyroid-stimulating antibodies directed at TSH receptors on follicular cells. • It is named for Robert Graves, an Irish physician, who was the first to describe this form of hyperthyroidism about 150 years ago.
ETIOLOGY • The trigger for auto-antibody production is not known. • Genetic predisposition – HLA DR3 • Since Graves' disease is an autoimmune disease which appears suddenly, often quite late in life, it is thought that a viral or infection may trigger antibodies which cross-react with the human TSH receptor (a phenomenon known as antigenic mimicry, also seen in some cases of Type I diabetes). • Yersiniaenterocolitica Reference: http://en.wikipedia.org/wiki/Graves%27_disease
CLINICAL FEATURES • Triad: • Goiter including the pyramidal lobe • Thyrotoxicosis • Exophthalmos • Symptoms: • Heat intolerance • Thirst • Sweating • Weight loss despite adequate caloric intake • Amenorrhea • Tachycardia or atrial fibrillation • Congestive heart failure
PE: • Weight loss • Flushing • Warm and moist skin • Inappropriate sweating • Tachycardia • Widening of pulse pressure • Fine tremor • Muscle wasting • Hyperactive tendon reflexes • Pretibialmyexedema • Gynecomastia • Audible bruit over the gland • Laboratory Findings: • Decreased TSH • Increased circulating T3/T4 levels • Increased circulating thyroid autoantibodies • Thyroid stimulating immunoglobulins (TSI) • Tyhroid stimulating antibodies (TSAb) • Radioactive iodine scan shows diffuse uptake through the gland of 45-90 percent.
MANAGEMENT • Medical: • Propylthiouracil (PTU) • Methimazole (Tapazole) • Carbimazole • Beta-blockers (Propanolol)
Relapse rate in 12-18 months • Risk for fetalgoiter, hypothyroidism • No morbidity related after surgery • Treatment of choice for small goiters and pregnant patients (PTU) • Euthyroid state is achieved in 4-6 weeks
Radioactive Iodine • Ease of treatment • Highly effective especially in diffuse goiters • No morbidity related to surgery • Treatment of choice for failed surgical management • The effect is seen in 1.5-4 months • Standard dose = 10 mCl = 8500 cGy
Surgery • Complete and permanent control of toxicity • Rapid control of symptoms • Removal of mass • Treatment of choice for huge goiters • Needs pre-operative preparation • Overall morbidity of 1-2%
Toxic MultinodularGoiter • Usually occur in individuals older than 50 years of age who often have a prior history of a nontoxic multinodulargoiter • Over several years, enough thyroid nodules become autonomous to cause hyperthyroidism. • Similar to Graves’ disease, but symptoms and signs of hyperthyroidism are less severe and extrathyroidal manifestations are absent. • May present with atrial fibrillation or palpitations, tachycardia, nervousness, tremor or weight loss. • Low TSH, normal or minimally increased T4, elevated T3, T3>T4.
Toxic MultinodularGoiter • Thyroid scan – heterogenous uptake with multiple regions of increased and decreased uptake. • 24hr uptake of radioiodine may not be increased. • Management • Antithyroid drugs + beta blockers – normalize thyroid function and address the clinical features of thyrotoxicosis, but often stimulates the growth of the goiter; spontaneous remission does not occur. • Radioiodine – treat areas of autonomy, decrease the mass of the goiter • A trial of radioiodine should be considered before subjecting patients to surgery.
Toxic MultinodularGoiter • Surgery • Definitive treatment of underlying thyrotoxicosis and goiter. • Subtotal thyroidectomy is the standard procedure. • Patients should be rendered euthyroid using antithyroid drugs before operation.
Toxic Adenoma • A solitary, autonomously functioning thyroid nodule • Typically occurs in younger patients • (+) thyroid nodule with symptoms of hyperthyroidism • Size is at least 3cm before hyperthyroidism occurs. • Absent clinical features suggestive of Graves’ disease or other causes of thyrotoxicosis
Toxic Adenoma • Thyroid scan – definitive diagnostic test • Focal uptake in the hyperfunctioning nodules • Diminished uptake in the remained of the gland • Suppression of the activity of the normal thyroid
Toxic Adenoma • Radioiodine ablation – treatment of choice • 131I is concentrated in the hyperfunctioning nodule with minimal uptake and damage to normal thyroid tissue. • Relatively large doses – correct thyrotoxicosis in about 75% of patients within 3 months. • Hypothyroidism occurs in <10% of patients over the next 5 years.
Toxic Adenoma • Surgical resection • Limited to enucleation of the adenoma • Lobectomy • Preservation of thyroid function • Low risk of hypoparathyroidism • Low risk of damage to the recurrent laryngeal nerve
Toxic Adenoma • Medical therapy using antithyroid drugs and beta blockers – normalize thyroid function but is not an optimal long term treatment • Ethanol injection under ultrasound guidance • Repeated injections – often >5 sessions • Reduce nodule size
Solitary Thyroid Nodule • Present in approximately 4 percent of the population • Pain is unusual. When present, it should raise suspicion for intrathyroidalhemorrhage in a benign nodule, thyroiditis, or malignancy. • History of hoarseness - may be secondary to malignant involvement of the recurrent laryngeal nerves • Risk factors for malignancy – exposure to ionizing radiation and family history of thyroid and other malignancies associated with thyroid cancer.
Solitary Thyroid Nodule • Mass moves with swallowing. • Hard, gritty of fixed nodules are more likely to be malignant. • Most are euthyroid. • If a patient with a nodule is found to be hyperthyroid, the risk of malignancy is approximately 1 percent. • FNAB – most important diagnostic test • Benign – 65% (includes cysts and colloid nodules) • Suspicious – 20% • Malignant – 5% • Nondiagnostic – 10%
Solitary Thyroid Nodule • Ultrasound • For detecting nonpalpable thyroid nodules • For differentiating solid from cystic nodules • For diagnosing suspicious nodules with microcalcifications • For identifying adjacent lymphadenopathy • CT and MRI – unnecessary in except for large, fixed, or substernal lesions. • 123I or 99mTc – rarely necessary, unless evaluating patients for “hot” or autonomous thyroid nodules
Solitary Thyroid Nodule • Malignant tumors – generally treated by total or near-total thyroidectomy • Simple thyroid cysts - resolve with aspiration in approximately 75 percent of cases • Unilateral thyroid lobectomy - if the cyst persists after three attempts at aspiration • Lobectomy • For cysts >4 cm in diameter • For complex cysts with solid and cystic components
Solitary Thyroid Nodule • Colloid nodule – should be observed with serial ultrasound and Tg measurements • Repeat FNAB if nodule enlarges • L-thyroxine – in doses sufficient to maintain a serum TSH level between 0.1 and 1.0 μU/mL. • 50% decrease in size • Thyroidectomy – if a nodule enlarges on TSH suppression, causes compressive symptoms, or for cosmetic reasons • Exceptions: Patient who has had previous irradiation of the thyroid gland or who has a family history of thyroid cancer. • In these patients total or near-total thyroidectomy is recommended. • High incidence of thyroid cancer (≥ 40%) • Decreased reliability of FNA biopsy