Thyroid and Parathyroid

thyroid. Treatment is provided in the form of a drink of 131I sodium iodide, the
dosage of which usually is calculated with a formula based on gland volume and 131I
uptake; the typical initial dose is about 10 mCi of 131I (approximately 8500 cGy).
Cure rate after initial therapy is dosage dependent; with 5 mCi, cure rate is 70 percent;
with 10 mCi, 87 percent; and with 15 mCi, 96 percent. The higher the initial dose, the
. earlier the onset and the higher the incidence of hypothyroidism
After standard treatment with radioiodine most patients become euthyroid within 2
months. Approximately 15 percent of patients are hypothyroid at 1 year, with a 3
percent increment each year thereafter. Six months after radioiodine treatment, 50
percent of patients are euthyroid, and the remainder are hyperthyroid or already
hypothyroid. Patients need long- term follow-up with TSH levels monitored on a
regular basis. Close monitoring is essential, because hypothyroidism and recurrent
. hyperthyroidism aggravate Graves' ophthalmopathy
The complications of 131I treatment include: (1) exacerbation of thyrotoxicosis with
arrhythmias; this usually becomes apparent within 10 days and may be a particular
problem in the elderly, precipitating cardiac failure or death; (2) overt thyroid storm
(rare but potentially life threatening); (3) hypothyroidism; (4) risk of fetal damage in
patients who are pregnant (women are advised not to become pregnant for 6 months
to 1 year after treatment); (5) worsening of eye signs, noted to be more common after
131I treatment than after surgery (33 percent compared to 16 percent); and (6)
. hyperparathyroidism
Surgical Treatment
Surgery is advised when radioiodine treatment is contraindicated, such as for young
patients, patients with Graves' ophthalmopathy, pregnant patients, patients with
suspicious thyroid nodules in Graves' glands, and patients with large toxic nodular
goiters with relatively low levels of radioiodine uptake. Thyroidectomy is the
treatment of choice in patients with very large goiters and severe thyrotoxicosis at
initial presentation. There is a higher failure rate with 131I treatment in these groups,
necessitating additional therapy. In the United States radioiodine is the usual
treatment for patients over 35 years of age with Graves' disease; in the United
Kingdom and many other countries thyroidectomy is more frequently used because it
is associated with less hypothyroidism and more rapid correction of hyperthyroidism.
The objective of thyroidectomy for Graves' disease should be the complete and
permanent control of the disease with minimal risk of morbidity in terms of nerve and
. parathyroid damage
Patients should be euthyroid before operation with antithyroid drugs that should be
continued up to the day of surgery. Many physicians prefer to treat patients with
Lugol's iodine solution (3 drops twice daily) in the 10 days before operation, and
some use propranolol. Preoperative treatment with iodine reduces the vascularity of
the gland. All these measures decrease the risk of thyroid storm, which can be
. precipitated by surgery in unprepared patients
Whether subtotal, near-total, or total thyroidectomy should be performed is
controversial. The most commonly undertaken procedure, and perhaps the safest in
terms of morbidity, is bilateral subtotal thyroidectomy, in which about 1 to 2 g of
thyroid tissue is left on both sides, or a total lobectomy on one side and a subtotal