The signs and symptoms
The signs and symptoms of hypothyroidism are vary, they are depending on the severity of the hormone deficiency. But in general, any problems you have tend to develop slowly, often over a number of years.
At first, you may barely notice the symptoms of hypothyroidism, such as fatigue and weight gain, or you may simply attribute them to getting older. But as your metabolism continues to slow, you may develop more-obvious signs and symptoms.
Hypothyroidism signs and symptom may include:
Fatigue
Increased sensitivity to cold
Constipation
Dry skin
Weight gain
Puffy face
Hoarseness
Muscle weakness
Elevated blood cholesterol level
Muscle aches, tenderness and stiffness
Pain, stiffness or swelling in your joints
Heavier than normal or irregular menstrual periods
Thinning hair
Slowed heart rate
Depression
Impaired memory
When hypothyroidism isn't treated, the signs and the symptoms gradually will become more severe. Constant stimulation of your thyroid gland to release more hormones may lead to an enlarged thyroid (goiter). In addition, you may become more forgetful, your thought processes may slow, or you may feel depressed.
Advanced hypothyroidism, known as myxedema, is rare, but when it occurs it can be life-threatening. Signs and symptoms include low blood pressure, decreased breathing, decreased body temperature, unresponsiveness and even coma. In extreme cases, myxedema can be fatal.
The Causes
The most common causes are surgical removal of your thyroid, autoimmune diseases, and radiation treatment.
Surgical Removal
This may be necessary to treat hyperthyroidism, or tumors of the thyroid gland. Hypothyroidism will occur when the entire gland is removed.
Autoimmune Diseases
These diseases cause the production of antibodies that attack your thyroid gland. Autoimmune thyroiditis, which can appear suddenly or develop over several years, is more common in women. Hashimoto’s thyroiditis and atrophic thyroiditis are the most common types.
Radiation Treatment
Radiation treatment for Hodgkin lymphoma and cancers of the head and neck can injure the thyroid gland. If this occurs, the gland cannot produce enough thyroid hormone to keep your metabolism running smoothly. Radioactive iodine (I-131) destroys the thyroid gland and can be used to treat people with Grave’s disease and thyroid cancer. Grave’s disease is an autoimmune disease that causes hyperthyroidism.
Other Causes of Hypothyroidism
Congenital Hypothyroidism
Some children are born without a thyroid gland or they may have one that doesn’t function properly.
Viral or Autoimmune Thyroiditis
When antibodies or viruses attack your thyroid, thyroid hormones can leak out. Sometimes all of the thyroid’s hormones are released into your blood at one time. When this happens, symptoms of thyroid excess or hyperthyroidism occur.
Medications
Lithium (used to treat bipolar disease), amiodarone (medication with high iodine content used to treat serious ventricular arrhythmias, interleukin 2 (anti-viral and anti-cancer agent), and interferon alpha (anti-viral agent) are medications that can cause hypothyroidism. This is more likely to occur in people who have a genetic tendency for autoimmune thyroid disease.
Pituitary Disease
The pituitary is the master gland that signals the thyroid how much hormone it needs to produce. If the pituitary is damaged by trauma, stroke, or tumor, the signal to release thyroxine can stop. This causes the thyroid to stop making thyroid hormone.
Not Enough or Too Much Iodine
The thyroid gland needs iodine to make T3 and T4. Iodine had to be obtained in the diet. Too little iodine can cause hypothyroidism and, ironically, too much iodine can
block the thyroid’s ability to make thyroid hormone.
Infiltration
Diseases like amyloidosis can cause the thyroid to become overwhelmed by abnormal proteins where the cells cannot function normally.
Groups at Higher Risk for Hypothyroidism
The following groups are at a greater risk for developing hypothyroidism:
women over age 50.
people with autoimmune diseases or a parent or grandparent with an autoimmune disease.
people given radioactive iodine or radiation therapy
people treated with antithyroid medication
those with a history of radiation to the neck and upper chest people with a partial thyroidectomy (removal of the thyroid)
post-partum females
