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Indications And Contraindications Of Surgery In Treating Hyperthyroidism And The Thyroid Storm
A General Overview
Indications for surgery are:
- Nodular toxic goiter
- Failure of drug therapy or serious toxicity of drugs, and
- Poor drug compliance, socioeconomic factors and desire for quick response.
Subtotal thyroidectomy is the operation of choice. The patient is given drug therapy before surgery to make him euthyroid. This is necessary to prevent thyrotoxic crisis. Two weeks prior to surgery, carbimazole is replaced by potassium iodide 60 to 100 mg per day in oder to reduce the size and vascularity of the gland. Surgery is effective in reducing toxic symptoms occurs in 10% cases. The immediate complications include recurrent laryngeal nerve palsy and damage to the parathyroid glands. On long follow up, 40-45% of cases may be seen to develop hypothyroidism.
Radio-iodide treatment: Currently I131 treatment has practically replaced thyroidectomy in the treatment of Grave’s disease in adults in many countries. Date from major centres show that 50% of patients are treated with I131, 35% with surgery and only 15% with antithyroid drugs alone. In India, radio-iodine treatment is available in many centers for routine use. I131 is the commonly used preparation. I125 can also be used for this purpose.
- Thyrotoxicosis with small or moderate sized gland.
- Recurrent thyrotoxicosis
- Masked hyperthyroidism
- Thyrotoxic heart failure
- Poor surgical risk.
- Pregnancy is an absolute contraindication since the isotope may reach the fetus and destroy its thyroid as well.
- In severely thyrotoxic patients I131 treatment may precipitate thyroid storm. Hence, treatment has to be undertaken with caution.
I131 dose: The thyroid will be effectively irradiated with 7000 rads. For this dose, each gram of thyroid tissue should receive 150 microcurles of I131. The average total dose is 8-10 millicuries. However, this dose leads to hypothyroidism in 30-70% of cases. Hence lower doses are preferred in many centers. After an initial dose of 4-5 millicuries, the dose is repeated after three to six months. I131 can be administered orally as a solution on an outpatient basis, but the excreta which contain significant amounts of radioactivity have to be disposed safely. Antithyroid medication should be withdrawn 48-72 hours before administering I131 and continued thereafter till the patient becomes euthyroid.
Exophthalmus In Thyroid Storm
Thyrotoxic Crisis (thyroid Storm)
This is caused by sudden release of thyroid hormones from the gland, spontaneously or immediately after surgery. Thyroid crisis is more frequent if surgery is undertaken during active thyrotoxicosis. Thyroid storm can be precipitated by I131 treatment also.
Thyroid crisis should be suspected if the patient develops high fever, severe tachycardia, restlessness, heart failure, peripheral vascular collapse or psychotic behaviour.
Treatment: Immediate administration of sedatives like diazepam, 10 mg given intramuscularly or intravenously and tepid sponging to bring down the temperature, help to arrest progress of the metabolic crisis. Intravenous fluids (glucose saline) and hydrocortisone 100mg are given in a dose of 300- 600mg/day is very effective in bringing down the condition. Antithyroid drugs are administered as a long-term measure, but they have no immediate effect. Prompt relief of the adrenergic symptoms is brought about by beta-adrenergic blockers like propanolol 10 mg intravenously or 40 mg orally.
There is no specific treatment for exophthalmos. During treatment of Grave’s disease, the exophthalmos subsides in some, but in others it remains unchanged or worsens. The treatment of exophthalmos is only empirical since the pathogenesis is ill-understood.
Irritation and watering of the eye are benefited by the used of eye drops containing corticosteroids, methyl cellulose or 5% guanethidine. Use of sunglasses with side shields and adoption of semi-upright position help to give further relief. Diuretics are also beneficial in some cases.
Malignant exophthalmos is also treated on the same lines, but systemic prednisolone 90-120mg daily is found to be beneficial. The eyes are protected from exposure keratitis by performing lateral tarsorrhaphy. Surgical decompression of the retro-orbital space (orbital decompression) is undertaken when the vision is threatened or papilledema develops. Irradiation of retro-orbital tissues may arrest the progress of exophthalmos and this is tired in severe cases.
© 2014 Funom Theophilus Makama