Hyperthyroidism

Hyperthyroidism develops when the body is exposed to excessive amounts of thyroid hormone. This disorder occurs in almost one percent of all Americans and affects women five to ten times more often than men. In its mildest form, hyperthyroidism may not cause recognizable symptoms. More often, however, the symptoms are discomforting, disabling, or even life-threatening.

Signs and Symptoms

When hyperthyroidism develops, a goiter (enlargement of the thyroid) is usually present and may be associated with some or many of the following features:

  • Fast heart rate, often more than 100 beats per minute
  • Becoming anxious, irritable, argumentative
  • Trembling hands
  • Weight loss, despite eating the same amount or even more than usual
  • Intolerance of warm temperatures and increased likelihood to perspire
  • Loss of scalp hair
  • Tendency of fingernails to separate from the nail bed
  • Muscle weakness, especially of the upper arms and thighs
  • Loose and frequent bowel movements
  • Smooth skin
  • Change in menstrual pattern
  • Increased likelihood for miscarriage
  • Prominent “stare” of the eyes
  • Protrusion of the eyes, with or without double vision (in patients with Graves’ disease)
  • Irregular heart rhythm, especially in patients older than 60 years of age
  • Accelerated loss of calcium from bones, which increases the risk of osteoporosis and fractures

Causes

Graves’ Disease:

(named after Irish physician Robert Graves) is an autoimmune disorder that frequently results in thyroid enlargement and hyperthyroidism. In some patients, swelling of the muscles and other tissues around the eyes may develop, causing eye prominence, discomfort or double vision. Like other autoimmune diseases, this condition tends to affect multiple family members. It is much more common in women than in men and tends to occur in younger patients.

Toxic Multinodular Goiter:

Multiple nodules in the thyroid can produce excessive thyroid hormone, causing hyperthyroidism.Typically diagnosed in patients over the age of 50, this disorder is more likely to affect heart rhythm. In many cases, the person has had the goiter for many years before it becomes overactive.

Toxic Nodule:

A single nodule or lump in the thyroid can also produce more thyroid hormone than the body requires and lead to hyperthyroidism. This disorder is not familial.

Subacute Thyroiditis:

This condition may follow a viral infection and is characterized by painful thyroid gland enlargement and inflammation, which results in the release of large amounts of thyroid hormones into the blood. Fortunately, this condition usually resolves spontaneously. The thyroid usually heals itself over several months, but often not before a temporary period of low thyroid hormone production (hypothyroidism) occurs.

Postpartum Thyroiditis:

Five to ten percent of women develop mild to moderate hyperthyroidism within several months of giving birth. Hyperthyroidism in this condition usually lasts for approximately one to two months. It is often followed by several months of hypothyroidism, but most women will eventually recover normal thyroid function. In some cases, however, the thyroid gland does not heal, so the hypothyroidism becomes permanent and requires lifelong thyroid hormone replacement. This condition may occur again with subsequent pregnancies.

Silent Thyroiditis:

Transient (temporary) hyperthyroidism can be caused by silent thyroiditis, a condition which appears to be the same as postpartum thyroiditis but not related to pregnancy. It is not accompanied by a painful thyroid gland.

Excessive Iodine Ingestion:

Various sources of high iodine concentrations, such as kelp tablets, some expectorants, amiodarone (Cordarone, Pacerone – a medication used to treat certain problems with heart rhythms) and x-ray dyes may occasionally cause hyperthyroidism in patients who are prone to it.

Overmedication with thyroid hormone:

Patients who receive excessive thyroxine replacement treatment can develop hyperthyroidism.They should have their thyroid hormone dosage evaluated by a physician at least once each year and should NEVER give themselves “extra” doses.

Diagnosis

Characteristic symptoms and physical signs of hyperthyroidism can be detected by a physician. In addition, tests can be used to confirm the diagnosis and to determine the cause.

TSH (Thyroid — Stimulating Hormone or Thyrotropin) Test:

A low TSH level in the blood is the most accurate indicator of hyperthyroidism. The body shuts off production of this pituitary hormone when the thyroid gland even slightly overproduces thyroid hormone. If the TSH level is low, it is very important to also check thyroid hormone levels to confirm the diagnosis of hyperthyroidism.

Other Tests

  • Estimates of free thyroxine and free triiodothyronine – the active thyroid hormones in the blood. When hyperthyroidism develops, free thyroxine and free triiodothyronine levels rise above previous values in that specific patient (although they may still fall within the normal range for the general population), and are often considerably elevated.
  • TSI (thyroid-stimulating immunoglobulin) – a substance often found in the blood when Graves’ disease is the cause of hyperthyroidism.
  • Radioactive iodine uptake (RAIU – a measurement of how much iodine the thyroid gland can collect) and thyroid scan (a thyroid scan shows how the iodine is distributed throughout the thyroid gland). This information can be useful in determining the cause of hyperthyroidism and ultimately its treatment.

Sometimes a general physician can diagnose and treat the cause of hyperthyroidism, but assistance is often needed from an endocrinologist, a physician who specializes in managing thyroid disease.

Treatment

Before the development of current treatment options, the death rate from severe was as high as 50 percent. Now several effective treatments are available and, with proper management, death from hyperthyroidism is rare. Deciding which treatment is best depends on what caused the hyperthyroidism, its severity, and other conditions present. A physician who is experienced in the management of thyroid diseases can confidently diagnose the cause of hyperthyroidism and prescribe and manage the best treatment program for each patient.

  • Antithyroid Drugs
  • Radioactive Iodine Treatment
  • Surgical Removal of the Thyroid
  • Other Treatments

Appropriate management of hyperthyroidism requires careful evaluation and ongoing care by a physician experienced in the treatment of this complex condition.