Hashimoto’s Thyroiditis – Autoimmune Thyroid Disease

What is Hashimoto’s Thyroid Disease?

Hashimoto’s thyroiditis is an autoimmune thyroid disease, which is one of the leading causes of hypothyroidism or underactive thyroid functioning. Hashimoto’s thyroiditis causes primary hypothyroidism, where the underactivity is due directly to poor thyroid functioning, rather than an interference with thyroid-pituitary regulating mechanism. Since Hashimoto’s thyroiditis is one of the  organ specific types of autoimmune disease, the dysfunction results from the body’s immune system ‘attacking’ the thyroid gland, when lymphocytes penetrate the thyroid gland and cause significant inflammation. This autoimmune thyroid disease affects more women than men and there is strong evidence to suggest a genetic link to  this form of thyroiditis, although the presence of other organ specific autoimmune diseases, like type I diabetes, may also be a consideration when assessing family history.

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Causes

As an autoimmune disease, the predominant mechanism of action leading to the condition is a result of thyroid antibodies created by the immune system. These antibodies trigger the immune cells to specifically attack the thyroid gland resulting in inflammation of the gland. The inflammation hampers the production of the thyroid hormones, triiodothyronine (T3) and thyroxine (T4). These hormones play an essential part in maintaining the body’s metabolism and the host of signs and symptoms associated with hypothyroidism is diverse due to the metabolic irregularities in the different cells and tissues within the body.

Signs & Symptoms

Due to the nature of Hashimoto’s thyroiditis, the signs and symptoms may vary depending on the tissues most affected as well as the degree of low thyroid hormone levels. The most common symptoms include :

  • Fatigue
  • Weight gain
  • Sleepiness and a lack of vitality
  • Intolerance or increased sensitivity to cold
  • Depression
  • Constipation
  • Painless enlargement of the thyroid gland (goiter)

Other signs and symptoms which may vary include :

  • Muscle aches, often termed as rheumatism.
  • Joint pains, especially of the small joints and may be mistaken for rheumatoid arthritis.
  • Swelling of the legs, face, neck and other parts of the body.
  • Dry, rough and/or itchy skin
  • Coarse, dry hair
  • Pale skin (pallor)
  • Changes in the voice due to increased pressure on the larynx caused by a swollen thyroid gland.
  • Changes in the hormone levels, particularly in women causing menstrual disturbances and even contributing to infertility.

While most of the signs and symptoms of Hashimoto’s thyroiditis is characteristic of hypothyroidism, some symptoms may appear to indicate hyperthyroidism or an overactive thyroid gland. Therefore, diagnosis of Hashimoto’s thyroiditis has to be confirmed through relevant blood tests.

Diagnostic Investigation & Blood Tests for Hashimoto’s Thyroiditis

A complete case history will highlight characteristic signs and symptoms associated with the condition as it progresses and coupled with a family history of autoimmune diseases, a differential diagnosis of Hashimoto’s thyroiditis may be reached. A painless enlargement of the thyroid gland may be noted upon palpating the gland and the other signs noted during physical examination may further contribute to the differential diagnosis. Hashimoto’s thyroiditis has to be confirmed with the proper blood tests, namely a thyroid profile, which is will test for the levels of T3, T4 and TSH (thyroid-stimulating hormone). The levels of T3 and T4 may be lower than normal to varying degrees, however the normal or increased levels of TSH indicates that there is no dysfunction in the stimulation of the gland. A follow up blood test for thyroid antibodies will verify the autoimmune mechanism of action thereby confirming the diagnosis of Hashimoto’s thyroiditis. In most cases, the combination of a comprehensive case history, coupled with physical findings and appropriate blood testing is sufficient to diagnose Hashimoto’s thyroiditis and a thyroid scan may not be necessary.

Treatment

Synthetic thyroid hormones, like levothyroxine, are most commonly used in Hashimoto’s thyroiditis and the dosage will vary depending on the severity of the condition and response to initial course of treatment. Hashimoto’s thyroiditis is a chronic condition and treatment is usually ongoing, however, the dosage of levothyroxine may have to be altered at different intervals to maintain normal thyroid hormone levels. Levothyroxine or any other medication used for the treatment of Hashimoto’s thyroiditis should not be altered without the supervision of a medical doctor or endocrinologist. The reduction of the signs and symptoms associated with Hashimoto’s thyroiditis does not mark a resolution of the condition and a progressive worsening of these signs and symptoms should not prompt an increased dosage without the appropriate medical supervision. This issue with patient compliance is one of the key obstacles affecting the effective management of Hashimoto’s thyroiditis coupled with concerns about the use of synthetic hormones in pregnancy.

Prognosis & Complications

If left untreated, the complications attributed to hypothyroidism can be severe, debilitating and potentially fatal. These mainly include heart disease, birth defects and ongoing depression. However with proper treatment and management of Hashimoto’s thyroiditis, these complications may be less severe or avoided altogether. In many cases, the weight gain associated with hypothroidism is a concern for patients due to aesthetic considerations. While the use of synthetic drugs will assist with the management of the condition, many sufferers will experience a slightly increased body weight throughout life and increasing the dosage of your medication should be avoided unless your doctor advises the change.


References

  1. Hashimoto’s Thyroiditis. Medicinenet
  2. Thyroid Antibodies. Labtestsonline
  3. Hypothyroidism. Merck
  4. Eltroxin.  Medbroadcast

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