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Thyroid gland


Endocrine glands

Hyperthyroidism

[Alternative Names]  [Definition]  [Causes, Incidence and Risk Factors]  [Symptoms]  [Signs And Tests]  [Treatment]  [Expectations (Prognosis)]  [Complications]  [Calling Your Health Care Provider]  [Prevention] 

Alternative Names

overactive thyroid; thyrotoxicosis

Definition

An imbalance in metabolism that occurs from overproduction of thyroid hormone.

Causes, Incidence and Risk Factors

The thyroid gland is located in the neck and produces several hormones that regulate growth, digestion, and the use of nutrients (metabolism). It is part of the endocrine system.
The thyroid gland responds to complex mechanisms to control the rates of hormone secretion.
Hyperthyroidism or thyrotoxicosis results from excess quantities of thyroid hormone within the body. Rather than being classified as a specific disease, it is classified as a syndrome that describes the characteristics resulting from this condition. The causes of hyperthyroidism include Graves' disease; tumors of the thyroid gland, pituitary gland, testes or ovaries; inflammation of the thyroid from a viral infection or other inflammation; ingestion of excessive amounts of thyroid hormone; and ingestion of excessive iodine. Graves' disease accounts for 85% of all cases of hyperthyroidism.
Risk factors are associated with the causes. The incidence is 1 out of 1,000 people.
Related topics:

• painless (silent) thyroiditis
• factitious hyperthyroidism
• hypothyroidism.

Symptoms

• weight loss
• increased appetite
• nervousness
• restlessness
• heat intolerance
• increased sweating
• fatigue
• muscle cramps
• frequent bowel movements
• menstrual irregularities in women
• goiter may be present

Additional symptoms that may be associated with this disease:

• weakness
• tongue problems
• thirst, excessive
• tearing, increased
• sleeping difficulty
• skin, clammy
• skin, abnormally dark or light
• skin blushing/flushing
• pulse, bounding
• paleness
• nausea & vomiting
• loss of muscle function/feeling
• muscle atrophy
• movement, uncoordinated
• menstruation, absent
• itching, overall
• heartbeat sensations
• hand tremor
• hair loss
• diarrhea
• breast development in men
• bone pain or tenderness
• blood pressure, high
• protruding eyes (exophthalmos)

Signs And Tests

Vital signs (temperature, pulse, rate of breathing, blood pressure) show increased heart rate. Physical examination reveals thyroid enlargement or goiter.
Laboratory tests that evaluate thyroid function:

• serum TSH is decreased
• serum T3, T4, thyroid resin uptake are elevated

This disease may also alter the results of the following tests:

• vitamin B-12
• visual field
• TSI
• triglycerides
• RT3U
• radioactive iodine uptake
• glucose test
• cholesterol test
• antithyroglobulin antibody
• ACE levels

Treatment

Treatment will vary depending on the cause of the condition and the severity of symptoms. Hyperthyroidism is treated with antithyroid medications, radioactive iodine, or surgery.
Beta-blockers (Propranolol) are used to treat some of the symptoms including rapid heart rate, sweating, and anxiety until the hyperthyroidism is controlled.

Expectations (Prognosis)

Hyperthyroidism caused by Graves' disease is usually progressive and has associated complications. Recurrences of hyperthyroidism are common.

Complications

• Cardiac complications include rapid heart rate, congestive failure, and atrial fibrillation.
• Thyroid crisis or "storm" is an acute worsening or exaggeration of the symptoms of hyperthyroidism that may occur with infection or stress.
• Fever, decreased mental alertness, and abdominal pain may occur and immediate hospitalization is indicated.

Calling Your Health Care Provider

Prevention

Prevention is related to the specific disorder causing hyperthyroidism. See the specific disorders.

The information provided herein should not be used for diagnosis or treatment of any medical condition. A licensed physician should be consulted for diagnosis and treatment of any and all medical conditions. (See disclaimer). Copyright 1999 adam.com, Inc. Any duplication or distribution of the information contained herein is strictly prohibited.

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