perthyroid origin, the thyroid function tests are abnormal and the muscular disorder is reversed when the thyrotoxicosis is relieved. Usually a consideration of the total clinical picture and assessment of TSH and FTI are sufficient to distinguish thyrotoxicosis from polymyositis, myasthenia gravis, or progressive muscular atrophy. True myasthenia gravis may coexist with Graves’ disease, in which case the myasthenia responds to neostigmine therapy. (The muscle weakness of hyperthyroidism may be slightly improved by neostigmine, but never relieved.) Occasionally electromyograms, muscle biopsy, neostigmine tests, and ACH-receptor antibody assays must be used to settle the problem.
TREATMENT OF THYROTOXICOSIS– SELECTION OF PRIMARY
Three forms of primary therapy for Graves’ disease are in common use today: (1) destruction of the thyroid by 131-I; (2) blocking of hormone synthesis by antithyroid drugs; and (3) partial or total surgical ablation of the thyroid. Iodine alone as a definitive form of treatment has been used in the past, but is not used today because its benefits may be transient or incomplete and because more effective methods have become available. Iodine is primarily used now in conjunction with antithyroid drugs to prepare patients for surgical thyroidectomy when that plan of therapy has been chosen. Roentgen irradiation was also used in the past.  Selection of therapy depends on a multiplicity of considerations [36.1]. Availability of a competent surgeon, for example, undue emotional concern about the hazards of 131-I irradiation, or the probability of adherence to a strict medical regimen might govern one’s decision regarding one program of treatment as opposed to another. All three methods provide satisfactory outcomes in over 90% of patients [36.2].. Fig. 2
Iodine-131 therapy is quick, easy, moderately expensive, avoids surgery, and is without significant risk in adults and probably late teenagers. The larger doses required to give prompt and certain control generally induce hypothyroidism, and low doses are associated with a frequent requirement for retreatment or ancillary medical management over one to two years. 131-I is used as the primary therapy in most persons over age 40 and in most adults above age 21 if antithyroid drugs fail to control the disease. Treatment of children with 131-I is less common, as discussed later.
Surgery, which was the main therapy until 1950, has been to a major extent replaced by 131-I treatment. As the high frequency of 131-I induced hypothyroidism became apparent, some revival of interest in thyroidectomy occurred. The major advantage of surgery is that definitive management is often obtained over an 8- to 12-week period, including preoperative medical control, and many adult patients are euthyroid after operation. Its well-known disadvantages include expense, surgery itself, and the risks of recurrent nerve and parathyroid damage, hypothyroidism, and recurrence. Nevertheless, if a skillful surgeon is available, surgical management may be used as the primary or secondary therapy in many young adults, as the secondary therapy in children poorly controlled on antithyroid drugs, in pregnant women requiring excessive doses of antithyroid drugs, in patients with significant exophthalmos, and in patients with coincident suspicious thyroid nodules. Early total thyroidectomy has been recommended for treating older, chronically ill patients with thyrotoxic storm if high-dose thionamide treatment, iopanoic acid, and glucocorticoids fail to improve the patient’s condition within 12 – 24 hours (36.4). Two recent surveys reporting trends in therapeutic choices made by thyroidologists have been published . In Europe, most physicians tended to treat children and adults first with antithyroid drugs, and adults secondarily with 131-I or less frequently surgery. Surgery was selected as primary therapy for patients with large goiters. 131-I was selected as the primary treatment in older patients. Most therapists attempted to restore euthyroidism by use of 131-I or surgery. In the United St