What is Hyperthyroidism?
Thyrotoxicosis is a disorder characterized by the over secretion of thyroidal hormones caused by over activity of the thyroid gland. In the condition known as Graves’ disease, the swelling is diffuse and general. Sometimes, however, it may come from a single, enlarged nodule (called toxic adenoma) or from several well-defined foci. They are essentially the same, although the latter tends to occur in older persons. In Graves’ disease there are often characteristic eye symptoms. It occurs more commonly in females, most probably between the ages of puberty and the menopause. There appears to be a genetic predisposition.
Onset may be hardly perceptible or rapid. Often there are complaints of feeling tired and lethargic. There may be an awareness-of the heart’s action, and breathlessness with activity. The patient is often nervous, tense and anxious. There is often a tremor of the hands, muscular weakness and probably bouts of diarrhea.
The thyroid gland tends to swell, and this swelling may be marked. As this happens a typical manifestation sets in, which is a protrusion and prominence of the eyes.
The patient may say she prefers cooler weather, dislikes hot climates, has an excellent appetite, but is losing weight. Heavy sweating is common, and there may be ankle swelling.
Generally the patient is tense, talkative and restless. The gland may show only moderate enlargement, and this is round and smooth. The doctor may hear a “bruit” on listening with the stethoscope over the gland.
There are general signs of anxiety and tension. The outstretched hands often show a fine tremor. Frequently the pulse rate is much higher than normal, tending to persist even when the patient is asleep at night. Normally the pulse reduces during sleep. Some patients gradually develop heart disorders.
The eye signs may be slight, or they may be dramatic and be the most obvious feature. The space between the eyelids increases and the lids tend to retract producing a condition called exophthalmos. This is common and is usually equal on both sides.
As the condition advances, and particularly in older persons, the symptoms of heart failure and other cardiac irregularities gradually set in, finally becoming the most important facet. This is more common in persons who may have preexisting heart disease.
The doctor confirms diagnosis by carrying out at least some of the many thyroid tests. The amount of the thyroid hormones in the blood is usually measured. However, in patients who may be taking other forms of medication, great care must be used in assessing the results, for medication can frequently interfere with the tests and give false results.
The doctor will prescribe a line of treatment designed to meet the needs of each patient. For this reason it will vary from case to case. An attempt is made to keep the patient in the so-called normal or “euthyroid state” for as much of the time as possible.
Various lines of action are involved. These are basically antithyroid drugs, radioactive iodine, or resorting to surgery and performing the operation called thyroidectomy. The antithyroid medicaments include carbimazole (probably the most effective for the average younger patient), methimazole, propyl and methyl-thiouracil.
The newer family of medicaments called the beta-blockers has been found useful, and propranolol and similar ones are now used, but may be inadequate on their own. Beta-blockers have the added advantages of reducing the rapid heart rate and relieving many of the other symptoms.
Surgery, usually subtotal thyroidectomy, produces permanent remission in most cases. What is left behind gradually regenerates to produce relatively normal thyroid function later on. Surgery is often used in younger patients where drug medication has been unsuccessful or followed by frequent recurrences. It is also the treatment of choice for the solitary toxic adenoma. The operation is not carried out until the patient has been brought to a normal state (euthyroid).
The chief problem with surgery is that a certain number of patients subsequently swing in the opposite direction and become hypothyroid. In some research studies the figure has been as high as 40 per cent occurring within a year of operation. Often this requires the regular use of thyroxine for the rest of one’s life. It is rare to see a recurrence of hyper- Radionuclide scan of the thyroid gland. thyroidism. Occasionally during operation there may be damage to the recurrent laryngeal nerve, and this may produce speech problems or even vocal cord paralysis. Apart from these drawbacks, the usual outcome is reasonably satisfactory.
Sometimes radioactive iodine treatment is used. This drug is taken up by the thyroid gland, and destructive rays interfere with normal thyroid function. It is often successful and relatively safe, and can be given on an outpatient basis, so is popular when compared to the need for hospitalization. It is usually reserved for treating patients over 45 years of age. It is good therapy if relapses occur after surgery, and some hospitals regard it as the first line of attack.
Summing up treatment, the British Medical Journal has said: “Antithyroid drugs are used in the young, in pregnancy and as a prelude to surgery; partial thyroidectomy is generally the best method of eradicating the disease in the young; and radioactive iodine in older patients. Whatever form of treatment is used, patients must be kept under observation by the doctor indefinitely.” These are the current thoughts on treatment.