6 min|Dr. Maya Kuczma
Autoimmune Disease 101: What is Graves' Disease?Immune Health
What is Graves' Disease?
Know the Numbers
- It is estimated that 200 million people worldwide have thyroid disease (1)
- Prevalence of thyroid disease is higher in women than men (2)
- In Canada, the most common form of hyperthyroidism is Graves’ disease (3)
A Healthy Thyroid
The thyroid is a small, butterfly shaped gland located in the front of our neck. In a healthy body, the hypothalamus produces thyrotropin-releasing hormone (TRH) to stimulate the pituitary gland to release thyroid-stimulating hormone (TSH). TSH ‘tells' the thyroid gland to produce more or less thyroid hormones - triiodothyronine (T3) and thyroxine (T4). T3 and T4 circulate throughout the body, affecting the health of our heart, skin, hair, intestines, brain, eyes, and metabolism. This entire cascade, from hypothalamus to the rest of the body, requires healthy hormonal signaling and response. The production of TSH requires protein, zinc, magnesium, and B12. The production of thyroid hormones requires many nutrients, including iodine, iron, zinc, and B vitamins.
Hypothalamus (TRH) —> Pituitary (TSH) —> Thyroid = T3, T4 —> heart, skin, hair, intestines, brain, eyes, metabolism
The thyroid gland predominantly produces T4, as well as a small amount of T3. T4 is then converted to T3 or reverse T3 (rT3). T3 is a much more potent thyroid hormone than T4; it stimulates our cell’s oxygen and energy consumption, directly affecting our metabolism. Conversion of T4 to T3 requires enzymes, as well as selenium and zinc.
T3 has to bind to receptors on our cells to have an effect. When these cells are healthy, and sensitive to this binding, T3 binds to a receptor on the surface of the cell, triggering a cascade of complex vital biological mechanisms. Cellular sensitivity is improved by many factors, including zinc, vitamin A, and exercise.
Evaluating the Thyroid
In order to measure the functioning of the thyroid gland, many Doctors test TSH levels. If the thyroid gland isn’t ‘listening’ to the signals from the pituitary, the pituitary will increase TSH release in an effort to create a ‘louder’ signal; this is reflected in an elevated TSH level. Once TSH elevates beyond the reference range, you may be diagnosed with hypothyroidism.
Alternatively, if the thyroid is producing an excess of T3 and/or T4, the hypothalamus (and pituitary) respond by decreasing TRH and TSH, in an attempt to decrease the signal sent to the thyroid, thereby decreasing the production of thyroid hormones. This is known as a ‘negative feedback loop’. Once TSH drops below the reference range, you may be diagnosed with hyperthyroidism.
However, as we have learned from healthy thyroid physiology, TSH is only one component of a very complex system. By testing only TSH, we are evaluating one step in this system - how the pituitary is ’talking to’ the thyroid. It can be helpful to evaluate the entire thyroid cascade, by testing TSH, T3, T4, rT3, as well as thyroid antibodies, to fully evaluate the thyroid, and determine the cause of dysfunction.
Particularly in cases where TSH is abnormal, it is vital to examine whether the hypothyroidism or hyperthyroidism is the result of an autoimmune condition, such as Hashimoto’s or Graves’ disease.
In order to evaluate the health of your thyroid, your Doctor may order:
- Free T3
- Reverse T3 (rT3)
- Free T4
- Thyroid peroxidase antibody (TPO)
- Thyroglobulin antibody (TGAb)
- Thyroid-stimulating immunoglobulins (TSI)
- Thyroid stimulating hormone receptor antibodies (TSHRAb)
If your TSH level is decreased, additional diagnostic tests may be ordered to distinguish between Graves’ disease and other types of hyperthyroidism:
- Radioactive Iodine Uptake: a small dose of I-131 (radioactive iodine) is either injected or administered orally before your thyroid is scanned to determine how much iodine the thyroid absorbs; a high iodine intake is indicative of Graves’ disease
- Ultrasound: ultrasound can be a helpful method of examination, particularly when there is suspicion of thyroid nodules. If nodules are found, your Doctor may request a fine needle biopsy to evaluate the nodules further.
There are several types of hyperthyroidism, such as:
- hyperthyroidism due to a toxic nodule
- hyperthyroidism due to toxic multi-nodular goiter
- subacute thyroiditis (typically induced by a viral infection)
- postpartum thyroiditis
- hyperthyroidism due to excessive iodine intake
- medication-induced hyperthyroidism
- Graves’ disease
The most common form of hyperthyroidism is Graves Disease, in which the thyroid becomes overactive due to dysregulation of the immune system, via a process known as autoimmunity. In cases of Graves’ disease, thyroid-stimulating immunoglobulins (TSI) are elevated. Additionally, thyroid peroxidase antibodies (TPO) and thyroglobulin antibodies (TGAb) may be elevated.
It is important to determine whether you have non-autoimmune hyperthyroidism, or Graves' disease, as they require different treatments. Graves' disease requires treatment that takes into account the entire thyroid cascade, as well as the immune system. Additionally, Graves’ disease may respond poorly, or continue to progress, if the immune system is not accounted for within a treatment plan.
Symptoms of Graves' Disease
Symptoms of Graves’ disease are primarily due to the excess of T3 and T4 production by the thyroid. Elevated levels of these hormones can cause many signs and symptoms, such as:
- Heart palpitations, elevated heart rate
- Heat sensitivity, sweating
- Weight loss
- Increased appetite
- Frequent bowel movements, loose stool, diarrhea
- Muscle weakness, hand tremors
- Bulging eyes
- Pain, sensitivity, gritty sensation in the eyes
- Light sensitivity, double vision, vision loss
- Thickened, red skin on the shins
- Changes in menstrual cycle
- Reduced libido
- Enlargement of the thyroid gland
- Hoarse voice
In rare cases, as immune-mediated destruction of the thyroid continues, the thyroid can fluctuate between states of hypo- and hyper- activity, leading to complex symptoms that may mimic both Hashimoto’s disease and Graves’ disease.(4)
Do you have many of the symptoms of hyperthyroidism? Have you been diagnosed with hyperthyroidism, but your antibody levels weren’t tested? Or, are you receiving treatment for hyperthyroidism and wondering if there’s more you could be doing to support you body?
At Integrative, we’re here to help. Contact our reception - (604) 738-1012 - or [email protected] to take a step towards better health and vitality.