What is Hashimotos Thyroiditis Disease?

Hashimotos Thyroiditis is an Autoimmune disorder whereby the body produces antibodies against itself that leads to the destruction of the Thyroid gland thereby causing a Thyroid Disease known as Thyrotoxicosis in the early phase of Hashimotos Thyroiditis or Hypothyroidism in the late phase. Hashimotos Thyroiditis is also known as Chronic Lymphocytic Thyroiditis. This should not be confused with Graves’ disease which is also an autoimmune disease but results in Hyperthyroidism solely, because the antibodies produced in Graves disease do not attack the Thyroid gland but rather continuously stimulates it to produce excess thyroid hormones (Thyrotoxicosis).

The antibodies of the body are supposed to fight foreign substances that are not compatible with the body; but in Hashimotos Thyroiditis, instead of the body to see the thyroid gland as belonging to the body, it sees it as foreign and therefore mounts an attack on the thyroid gland. Because the thyroid gland is being destroyed in the early phase of Hashimotos Thyroiditis, the thyroid Hormones producing-cells release Thyroid hormones (Thyroxine T4 and Triiodothyronine T3) into the blood leading to excess of thyroid hormones in the body, a condition referred to as Thyrotoxicosis. When the Thyroid producing-cells become completely destroyed, there will be no more Thyroid hormones available in the body again and this causes a permanent condition known as Hypothyroidism or the Thyroid gland can be said to be Hypoactive or the body can be said to be Hypothyroid. Hypothyroidism means therefore that there are low Thyroid hormones in the body.

Hashimotos Thyroiditis therefore can cause both Hypothyroidism and Hyperthyroidism (Thyrotoxicosis) depending on the phase of the disease as explained above.

Hashimotos Disease causes a moderately enlarged Thyroid gland or a localized nodule in the anterior aspect (front of the neck) of the neck that is infiltrated by lymphocytes (struma lymphomatosa) and shows a high titer of antithyroglobulin when a blood test is done.

Hashimotos Thyroiditis Epidemiology

Hashimotos Disease occurs commonly in Middle age (45 to 65 year olds) although it affects all ages including children (in which case, it is a major cause of non-endemic goiter). It occurs more in women than in men with a ratio of 10-20: 1; that is, about 20 women are likely to have this before you see 1 man with it (or women are 10 to 20 times more likely to have it than men)

Types of Hashimotos Thyroiditis

Hashimotos Thyroiditis is classified into two: Focal thyroiditis and Diffused Thyroiditis

Focal Thyroiditis affects only a limited part of the Thyroid gland.

In Diffused thyroiditis, the thyroid gland is firm, nodular and uniformly enlarged because the pathology affects different parts of the gland and the gland becomes atrophy with replacement of normal tissues by fibrous tissue and lymphocytes.

Pathophysiology of Hashimoto thyroiditis. The Three proposed models for mechanism of thyrocyte destruction in Hashimoto disease.

Hashimotos Thyroiditis Causes

What causes Hashimotos Thyroiditis?

The cause of Hashimotos Thyroiditis Disease is genetic. Adults with Down syndrome (Trisomy 21) or Turner syndrome have increased risk of developing this disease. Having a family member with Hashimotos Thyroiditis increases your chance of having it; having a related autoimmune disorder predisposes to having Hashimoto disease (see related autoimmune disorders below). Other causes of Thyroid disorders in general may cause this disease also such as infections, selenium deficiency, and exposure to radiation causes gene mutation and may cause thyroiditis or increase intake of iodine may trigger it; however, the exact cause of Hashimotos Thyroiditis is not completely known.

Hashimotos Thyroiditis Symptoms and Signs

Since the early and late phases of Hashimotos Thyroiditis vary, their symptoms and signs vary depending on the stage of the disease.

Signs and Symptoms of Early Phase of Hashimotos Thyroiditis

1. Swelling of the neck (frontal aspect), known as a goiter
2. Weight loss despite increased appetite
3. Heat intolerance (The Person is seen sweating even when the weather is normal with other people)
4. Irregular menstrual cycle
5. Miscarriages in Pregnancy
6. Increase passage of feces/stool per day (Hyper-defecation)
7. Anxiety and restlessness
8. Bulging or protruding eyes

At this phase, the symptoms are similar to that of Hyperthyroidism and hence may be confused for Graves disease.

Signs and symptoms of Late Phase Hashimotos Thyroiditis

1. Increase in weight despite decreased in appetite
2. Feeling of Tiredness (fatigue)
3. Inability to tolerate cold (Abnormal sensitivity to cold) Cold Intolerance
4. Inability to pass stool normally (Constipation)
5. Infertility (pregnancy will not be possible)
6. Abnormal and irregular Menstrual cycle
7. Mood disorders such as Depression
8. Swelling of the face
9. Dry skin
10. Slow heart beat the heart rate is slow (Bradycardia)

In this phase, the symptoms are classical of Hypothyroidism.

Picture of Features of Hashimoto’s Thyroiditis as seen by the Microscope

Hashimotos Thyroiditis Laboratory Investigations and Diagnosis

Diagnosis of Hashimotos Thyroiditis is done by taking a good clinical history and examination. It is then confirmed by carrying out a blood test in the laboratory. A diagnosis of Hashimotos Thyroiditis is made when the following is found in the blood test result:

1. Elevated levels of anti-thyroglobulin
2. Thyroid Function Test (TFT) will show low blood levels of Thyroxine and Triiodothyronine in the late stage of the disease but high in the early stage and there is elevated level of TSH.
3. Fine Needle Biopsy shows infiltration of the thyroid gland by lymphocytes. The thyroid follicles are atrophic and are lined in many areas by epithelial cells distinguished by the presence of abundant eosinophilic, granular cytoplasm, termed Hrthle cells. This is a metaplastic response of the normally low cuboidal follicular epithelium to ongoing injury. When a fine-needle aspiration biopsy is done and there is presence of Hurthle cells together with infiltrating lymphocytes, it is characteristic of Hashimoto thyroiditis.
4. There is no response to TSH stimulation test
5. Clinically, the anterior neck swelling is may be painful and is warm to touch that is, there is inflammation. In fact, the Pain is the major concern of the Patient and not even the swelling as compared to those coming with simple non-toxic goiter for cosmetic reasons.

Hashimotos Thyroiditis Treatment

Treatment of Hashimotos Thyroiditis includes control of the pain caused by inflammation, inhibiting the auto antibodies and replacing the thyroid hormones throughout the life of the patient because there is no permanent cure for it. This is done by the following:

1. Use of Prednisolone, a steroid that helps with both the pains and the autoimmune effect
2. Taking of Levothyroxine throughout life
3. Subtotal thyroidectomy surgery may be required when there is a large goiter that causes difficulty in swallowing or breathing (pressure symptoms)

Hashimotos Thyroiditis diet

Since the problem in this disorder is low level of thyroxine, anyone having Hashimotos Thyroiditis should avoid goitrogenic diet (that is, food containing ingredients that binds iodine and makes it unavailable for the body such as Cabbage, Turnip, Broccoli (all Brassica family vegetables) and Cassava etc these are known as goitrogens) as they may hasten the progression of the disease. However, too much of iodine intake is also harmful too as the excess iodine intake is itself a trigger too. Use of iodized salt that have the required amount of iodine is better and eating of gluten free diet.

Some Medical conditions associated with Hashimotos Thyroiditis

1. Addison’s disease
2. Diabetes mellitus
3. Graves’ disease
4. Hypoparathyroidism
5. Premature ovarian failure
6. Pernicious anemia.
7. Rheumatoid arthritis
8. Sjogren’s syndrome
9. Ulcerative colitis
10. Systemic lupus erythematosus (SLE)
11. Hemolytic anemia

Complication of Hashimotos Thyroiditis

1. Increased risk of developing cardiovascular diseases as increased levels of low density lipoproteins (LDL) caused by prolonged Hypothyroidism is dangerous to the heart.
2. Myxedema (drowsiness and unconsciousness follows) may occur and it is life threatening condition
3. Depression which may lead to suicidal tendencies

Hashimotos Thyroiditis Prognosis

A few of those who have long standing Hashimotos Thyroiditis may develop cancer of the lymph nodes known as Lymphoma. However, this occurs once in a thousand of cases.