Hashitoxicosis is an autoimmune thyroid condition that can occur for long periods, causing transient symptoms from time to time. Alternately, it can occur as a transitional phase as patients from autoimmune hyperthyroidism to autoimmune hypothyroidism or from autoimmune hypothyroidism to autoimmune hyperthyroidism.
Autoantibodies in Hashitoxicosis
- Thyroglobulin antibodies
- Blocking TSH receptor antibodies
- TPO antibodies
- Stimulating TSH receptor antibodies (thyroid stimulating immunoglobulins or TSI)
Patients with autoimmune hypothyroidism can have thyroglobulin antibodies or blocking TSH receptor antibodies, both of which are known to destroy thyroid cells. Thyroglobulin antibodies are seen in Hashimoto’s thyroiditis and blocking TSH receptor antibodies are seen in patients with atrophic thyroiditis. In addition, patients typically have thyroid peroxidase (TPO) antibodies, which are considered markers of inflammation. TPO antibodies also cause thyroid inflammation and thyroid disease to persist, interfering with the healing process.
Patients with Hashitoxicosis also have stimulating TSH receptor antibodies although their levels may not reach the high levels (1.3 or 130 percent activity) that cause hyperthyroidism in patients with Graves’ disease.
Thyroid Symptoms
In Hashitoxicosis, patients experience variable symptoms of hyperthyroidism that may change over time. Common symptoms include headache, hot flashes, irritability, increased appetite, weight loss, muscle weakness, increased heart rate, increased systolic blood pressure, atrial fibrillation, increased hair and nail growth, nervousness, tremor, nausea, mood disturbances, hives, and palpitations. However, hives and palpitations may also occur as a symptom of hypothyroidism.
Symptoms of hyperthyroidism in Hashitoxicosis may increase during times of stress and they may persist for long periods. In addition, they may also occur only at certain times of day, for instance, when stress levels are highest. Because thyroid hormone is very potent, even slight rises in thyroid hormone levels in which levels remain within the normal range, can cause symptoms associated with hyperthyroidism.
Similar to symptoms in hyperthyroidism and hypothyroidism, symptoms in Hashitoxicosis can vary in their severity and this variability can change over time. Many things, including infection and stress, can increase the effects of thyroid hormone. Patients with only negligible rises in thyroid hormone can have more severe symptoms than patients whose TSH levels fall into the range consistent with subclinical hyperthyroidism.
Individuals with Hashitoxicosis are at high risk for Graves’ ophthalmopathy (thyroid eye disease or TED). TSH receptor antibodies are known to contribute to trigger Graves’ ophthalmopathy and worsen symptoms. Patients in the early phases of Hashitoxicosis may have normal thyroid function tests because of their blocking TSH receptor antibodies blocking TSI from reacting with thyroid cells. In this case, patients may be diagnosed with euthyroid Graves’ disease.
Diagnosis
Changes consistent with Hashitoxicosis such as Hurthle cells and enlarged thyroid cells can be seen on thyroid biopsy. The I123 uptake is generally low or normal, and tests for thyroglobulin or blocking TSH receptor antibodies and stimulating TSH receptor antibodies are positive (higher than the normal range of less than 2 percent activity). Symptoms are also an important component in diagnosis.
Treatment
Treatment varies depending on thyroid function tests although thyroid replacement hormone is generally used to correct hypothyroidism. In cases where goiter is larger and thyroid antibody levels are unusually high, thyroid replacement hormone is usually administered in higher doses to keep TSH suppressed to low levels. TSH is known to increase thyroid cell growth and increase goiter.
Studies show that selenium supplements lower TPO antibodies, helping reduce persistent thyroid inflammation and allowing symptoms to resolve. Avoiding environmental triggers of autoimmune thyroid disease, such as excess dietary iodine, aspartame, and stress is also recommended.
Elaine Moore - I'm a retired medical technologist and medical writer with more than 30 years experience working in hospital laboratories. Currently, I ...
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