HYPOTHYROIDISM
What is Hypothyroidism?
A condition of decreased hormone production by the thyroid gland
that is caused by disease of the gland.
Hypothyroidism caused by the inability of the thyroid gland to make hormone is called primary hypothyroidism. Worldwide, the most common cause of primary hypothyroidism is deficiency of the element iodine. In the United States, the most common cause is destruction of the thyroid gland by the immune system, a condition called Hashimoto’s thyroiditis.
Other causes of primary hypothyroidism include surgical removal of part or all of the thyroid gland, radioactive iodine for treatment of hyperthyroidism (over active thyroid), radiation exposure to the neck, X-ray contrast agents, and certain drugs such as lithium. In some cases the cause of hypothyroidism is unknown.
What are the Symptoms of Hypothyroidism?
Early symptoms:
- Weakness Fatigue
- Cold intolerance
- Constipation
- Weight gain
- Depression Joint or muscle pain
- Thin, brittle fingernails
- Thin, brittle hair
- Pale color
Late symptoms:
- Slow speech
- Dry flaky skin
- Thickening of the skin
- Puffy face, hands and feet
- Decreased taste and smell
- Thinning of eyebrows
- Hoarseness of voice
- Menstrual disorders
How is Hypothyroidism Diagnosed?
Physical examination may reveal a small gland, though sometimes the gland is normal in size or even enlarged (goiter). Other physical findings include pale, yellow and dry skin, thin, brittle hair, loss of the edges of the eyebrows, coarse facial features, firm swelling of the arms and legs, and slow muscle relaxation when reflexes are tested. Vital signs may reveal a slow heart rate, low blood pressure and low temperature. A chest X-ray sometimes reveals an enlarged heart.
Laboratory tests to determine thyroid function include:
T4 test (low)
resin T3 uptake (low)
serum TSH (high)
Additional laboratory abnormalities may include:
increased cholesterol levels
increased liver enzymes
increased serum prolactin
low serum sodium
a complete blood count (CBC) shows anemia
How is Hypothyroidism Treated?
The purpose of treatment is to replace the deficient thyroid
hormone. Levothyroxine (T4) is the most commonly used medication,
but a preparation of T3 is also available. The lowest dose effective
in relieving symptoms is given. Life-long therapy is needed
as relapses will occur if therapy is interrupted. Medication
must be continued even when symptoms subside.
