Thyroid Disorders in TS: The Definitive Guide

This post is based on the recent webinar by Dr. Schweiger on “Thyroid Disorders in Turner Syndrome.” It briefly highlights the two common thyroid-related autoimmune conditions, hypothyroidism and hyperthyroidism, that greatly affect the Turner Syndrome community—hypothyroidism and hyperthyroidism.

Note: The information in this post is educational. It does not replace medical advice from your doctor(s). Always consult with a medical professional regarding any specific health concerns.

What are some key terms I need to know to understand Thyroid Disorders?

Autoimmune disease: A condition in which your immune system attacks your body, by mistake.
Lymphocytes: Type of white blood cells that act as a part of the immune system for protection.
Antibodies: A protein that binds to foreign invaders such as viruses, bacteria, and foreign substances in the blood.
Thyroiditis: The inflammation of the thyroid, a small gland below Adam’s apple at the base of the neck.
Hashimoto’s thyroiditis: An autoimmune disease in which your immune system attacks your thyroid.
Celiac disease: An immune disease in which people can’t eat gluten because it will damage their small intestine.
Alopecia areata: An autoimmune disorder that causes unpredictable hair loss.
Juvenile rheumatoid arthritis: is a form of arthritis in children. Arthritis is swelling and tenderness of the joint(s).
Karyotype: is the number and visual appearance of the chromosomes in the cell nucleus of an organism.
Free T4 (thyroxine): is one of the two major hormones produced by the thyroid.
TSH (thyroid stimulating hormone): is a hormone produced by a gland in the brain to stimulate thyroid to produce T4.
Immunoglobins: are a type of protein that function as antibodies or receptors in the body

An Overview of Autoimmunity in Turner Syndrome

Generally, Turner syndrome (TS) increases the risk of developing autoimmune disorders. The genetic basis of this is unknown, but we do see a decrease in the CD4/CD8 lymphocyte ratio in the individuals. Developing an autoimmune disorder can have important implications. For instance, an autoimmune disorder such as Hashimoto’s thyroiditis often leads to hypothyroidism and is most common among individuals with TS. As per Dr. Schweiger, the lifetime increased risk for thyroiditis among individuals with TS is approximately 30 percent.

In Hashimoto’s thyroiditis, the thyroid is attacked by the antibodies (thyroid peroxidase antibodies) by mistake. This is because the immune system becomes overactive and mistakes healthy body tissues as foreign and attacks them. Eventually, the gland would not be able to produce thyroid hormones that leads to hypothyroidism. Though whole process can take years to develop as a person has thyroiditis for about 10 years on average before they finally receive diagnoses.

Other autoimmune disease associated with TS include hyperthyroidism, celiac disease, type I diabetes, alopecia areata, and juvenile rheumatoid arthritis. In this article, we will primarily focus on hypothyroidism and hyperthyroidism associated with autoimmune thyroid disease that are reported to be higher among individuals with TS.

What is Hypothyroidism?

Hypothyroidism is a condition in which your body does not produce enough thyroid hormones. In girls with TS, the natural course of hypothyroidism is usually more severe than general population. So, they require continued monitoring of their thyroid function from 4 years of age onwards. Dr. Schweiger notes that the TS Study Group Consensus suggests a screen for the thyroid dysfunctions for all girls at diagnosis of TS. They should also undergo annual measurements of free T4 and TSH from early childhood and throughout life-span.

Symptoms of Hypothyroidism in Children:

Short Stature or slow growth
Rough, dry skin
Cold intolerance
Fatigue
Bruising easily
Delayed puberty

Signs of Acquired Hypothyroidism:

Obesity
Intolerance to cold
Depression
Hair loss
Slow heartbeat
Constipation
Menstrual changes
Fatigue
Joint pain

If you or your child is experiencing multiple symptoms or signs above, respectively, it is important to check with your medical provider to take necessary preventative measures. Additionally, it is important to monitor thyroid function especially if the child is not growing at a normal rate. Common test for hypothyroidism includes checking TSH, free T4, and microsomal antibodies level.

What treatments are available for Hypothyroidism?

One of the common treatment for hyperthyroidism is levothyroxine, which is given at low dose, about 0.025-0.05 mg daily at first. TSH level is monitored every 4-6 weeks, and the levothyroxine medication is increased in 0.0125 mg increments until the TSH level become normal. TSH level normally monitored every 6 months in kids and once a year in adults. Dr. Schweiger notes that it is better to take levothyroxine medication on empty stomach because it helps with the issue of absorption, and one of the options is to take it at bed time.

What is hyperthyroidism?

Hyperthyroidism occurs when thyroid glands produces too much thyroxine hormone due to overstimulation. Graves’ disease is a common autoimmune disorder that causes this overproduction.

Signs of hyperthyroidism in adults:

Prominent eyes
Redness to the eyes
Clubbing on the fingers

Signs of Graves' disease in Adolescents

Goiter
Tachycardia
Weight loss
Heat intolerance
Systolic hypertension
Advanced bone age
Increased pulse pressure
Secondary enuresis
Tremor
Ophthalmopathy or eye changes (such as, pain, exposure keratitis, Lid lag, and proptosis)
Hyperactivity

Hyperactivity
Palpitation
Sleep disturbance
Fatigue
Poor school performance
Neck fullness
Neck lump
Irritability
Nervousness
Increased stool frequency
Increased appetite
Emotional lability

What treatments are available for Hyperthyroidism?

The evaluation of hyperthyroidism includes the documentation of free T4 and TSH level as well as determining the cause through thyroid stimulating immunoglobin (TSI) test and radioactive iodide uptake scan. TSI are antibodies that tells your body to produce more thyroid hormone. TSI test measures the level of TSI or thyroid stimulating immunoglobin. In radioactive iodine uptake scan, the radioactive iodine is first taken up by the thyroid gland. The amount of iodine that is taken up by the gland is then measured for a given time period as a part of the test.

Hyperthyroidism treatment uses anti-thyroid medication. If the blood pressure gets high or if heart rate increases due to the medication, the patients are given beta blockers to get back to normal blood pressure and heart rate. Usually, the treatment is given for 18-24 months, and the patient is monitored to see if the condition goes away. If the condition goes away, patient can continue off the medication. If it does not go away or for any reason the patient is unable to take the medication, there are two definitive therapy options—near-total thyroidectomy (to remove the thyroid gland) and radioiodine ablation (to destroy thyroid tissue).

Side effects from thyroid medication:

Minor
- Rash
- Pruritus
- Hives
- Hair loss
- Nausea
- Decreased taste
- Joint pain

Severe
- Neutropenia
- Thrombocytopenia
- Stevens-Johnson Syndrome
- Cholestatic Jaundice
- Hepatitis

Note that Propylthiouracil (PTU) is no longer used because there is an increased risk of liver injury including liver failure and death in pediatric patients.

Takeaways

There is an association between thyroid diseases and Turner Syndrome (TS).
Children with TS have similar symptoms of hypothyroidism (underactive) and hyperthyroidism (overactive) as the general population.
Individuals with TS have a significantly higher frequency of autoimmune thyroid disease.
Optimal screening & early detection to help prevent complication from autoimmune disease in individuals with TS is important.
Thyroid disorder should be tested at the age of diagnosis and then annually after. In younger children, autoimmune disorder is more common than thyroid disorder, but it does not develop until the first few years of life (approx. 5 years).

This article was written by Dhruvi Patel, TSF Volunteer Blog Writer and edited by Ruchika Srivastava, TSF Volunteer Blog Editor.

Want to learn more about the association between auto-immune diseases in Turner’s Syndrome? Watch the Webinar here!