Hyperthyroidism (thyrotoxicosis)

This is much less common in most rural communities of the developing world than it is in the industrial world, but it is becoming more common in towns. Look for the signs listed above (21.7).

HYPERTHYROIDISM MEDICAL TREATMENT is the first choice for all cases, except where the disease arises in the nodule of a pre- existing nodular goitre (toxic nodule). Unfortunately, the relapse rate after medical treatment is 50%.

Admit the patient and give him:

(1) Tabs propanolol 40 mg three times daily (or some other [gb]-blocker). Within 48 hours there should be a fall in his pulse rate, and a diminution of his tremor, anxiety, restlessness, heat intolerance, and sweating. If there is no response in 48 hours, increase the dose to 80 or even 160 mg four times daily. If necessary continue for 2 or 3 months. Or, use another beta blocker.

CAUTION ! (a) 40 mg of propanolol orally is only effective for about 6 hours. If he presented with severe hyperthyroidism, severe symptoms, or even a crisis may follow the omission of a single dose. Regular doses are especialy important just before and immediately after surgery. (b) Don't use propanolol for long- term treatment.

(2) Tabs carbimazole 10 to 20 mg three times daily. Reduce this dose when his symptoms are controlled. He may experience symptomatic improvement in a week, but you may have to wait 3 to 6 weeks for an objective clinical response. Slowing of the pulse and weight-gain are the most reliable signs of improvement. When you judge him to be euthyroid reduce the dose to between 2.5 to 5 mg three times a day. Continue treatment for 18 months to 2 years if necessary. His hyperthyroidism may remit spontaneously, so that he needs no further treatment. Watch for the side effects of carbimazole (rashes etc.)

If he relapses ([mt]50% chance), advise surgery or a second course of medical treatment. The latter only succeeds in 25% of cases.

SURGICAL TREATMENT. He should be euthyroid before surgery. If possible refer him untreated, so that the expert can assess his clinical state before treatment starts. If this is impractical, treat him with propanolol and carbimazole for 6[nd]8 weeks before the expected date of the operation. Most surgeons give Lugol's iodine 1 ml daily for 10 days preoperatively to reduce vascularity. Beta blockers are continued up to the operation and for 10 days afterwards.

CAUTION ! It is dangerous to operate on thyrotoxic patients who have not had antithyroid drugs for 6[nd]8 weeks preoperatively. Even then, postoperative thyrotoxic crises occur. Thyroidectomy is not an operation for the generalist!

The recurrence of hyperthyroidism after a bilateral subtotal thyroidectomy is very unusual. However, 30% of patients become hypothyroid within 10 years and need l-thyroxine 100 to 200 micrograms daily.