Thyroid Disorders - Everything You Wanted To Know!

Thyroid gland is a butterfly shaped gland in the front of the neck. It encircles the windpipe or the trachea. It is about 4 cms in height and weighs about 18 gms. This gland is responsible for the secretion of thyroid hormones. Hormones are chemicals produced by special glands like thyroid, adrenals, ovaries etc. They act as messengers and are carried by the blood to the various target organs. Thyroid disorders are conditions that affect the thyroid glands. It plays an important role in regulating numerous metabolic processes throughout the body. The Thyroid gland is located below the adam’s apple wrapped around the trachea.

Thyroid disease is a common problem that can cause symptoms because of over- or under-function of the thyroid gland. The thyroid gland is an essential organ for producing thyroid hormones, which maintain our body metabolism. The thyroid gland is located in the front of the neck below the Adam's apple. Thyroid disease can also sometimes lead to enlargement of the thyroid gland in the neck, which can cause symptoms that are directly related to the increase in the size of the organ (such as difficulty swallowing and discomfort in front of the neck).

Thyroxine T4 is the primary hormone developed by the Thyroid gland. A small portion of the T4 released from the gland is converted to Triiodothyronine (T3) which is the most active hormone.

Hyperthyroidism: Too much thyroid hormone results in a condition known as hyperthyroidism. Affects about 1 percent of women. It's less common in men.

Grave’s disease is the most common cause of hyperthyroidism.

Symptoms:

• Restlessness
• Nervousness
• Irritability
• racing heart
• Increased sweating
• Shaking
• Restlessness
• Trouble sleeping
• Thin skin
• Brittle hair
• Nails
• Weight loss
• Muscle weakness

Causes:

1. Toxic adenomas: Nodules develop in the thyroid glands and begin to secrete thyroid hormones upsetting the body's chemical balance.
2. Subacute thyroiditis: Inflammation of the thyroid that causes the gland to leak excess hormones, resulting in temporary hyperthyroidism that lasts a few weeks but may persist for months.
3. Pituitary gland: Malfunctions or cancerous growths in the thyroid gland. Although rare, hyperthyroidism can also develop from these causes.

Treatments for hyperthyroidism: destroy the thyroid gland or block it from producing its hormones.

1. Antithyroid drugs: such as methimazole (Tapazole) prevent the thyroid from producing its hormones.
2. Radioactive iodine: a large dose of it damages the thyroid gland. A pill is given by mouth. As thyroid gland takes in iodine, it also pulls in the radioactive iodine, which damages the gland.
3. Surgery: Surgery can be performed to remove your thyroid gland.

Hypothyroidism: Inadequate production of hormones by the thyroid gland is termed as hypothyroidism. This is also called Underactive thyroid state. Hypothyroidism can make the body’s development to slow down and reduces metabolism rates. Since the body needs some amount of thyroid for energy production and drop in hormone production leads to lower energy levels.

Symptoms:

• Fatigue
• Dry skin
• Increased sensitivity to cold
• Memory problems
• Constipation
• Depression
• Weight gain
• Slow heart rate
• Coma

What are the causes of Hypothyroidism?

Hypothyroidism can be caused by a number of factors:

1. Hashimoto's thyroiditis: This is the commonest cause. This is an autoimmune disorder (normally body’s defence system fight against external infections. In autoimmune disorder the defence system attacks the healthy cells of the body by mistake). In Hashimoto’s thyroiditis the immune system/defence system produces antibodies that attack the thyroid gland and destroy it.
2. Iodine deficiency in diet: For the production of thyroid hormones iodine is very important. The body does not produce iodine normally, so it needs to be supplemented from outside. Iodine is mainly present in the food we eat. It is mainly present in shellfish, salt-water fish, eggs, dairy products. If a person does not eat iodine rich foods, he may end up with iodine deficiency leading to hypothyroidism. Currently, this causative factor is on the decline due to government initiative of table salt with iodine.
3. Surgery: Surgery to remove thyroid gland (for e.g. thyroid cancer treatment, overactive thyroid etc.)
4. Radiation to the neck (to treat cancer in the neck area): The thyroid gland cells are damaged due to the radiation.
5. Treatment with radioactive iodine: This treatment is used for managing hyperthyroidism/overactive thyroid, where the thyroid gland produces excessive thyroid hormones. One of the treatment modalities is by radioactive iodine. Sometimes this radiotherapy destroys normal functioning cells which lead to hypothyroidism.
6. Certain medicines: Certain medicines used to treat heart conditions, cancer, psychiatric conditions etc. – for e.g. amiodarone, lithium, interleukin-2, interferon-alpha.
7. Pregnancy: Pregnancy (the reason is unclear but it has been noticed that the thyroid may get inflamed after delivery – this is called Postpartum thyroiditis.
8. Damage to the pituitary gland: Pituitary gland is a gland which is present in the brain. It produces a hormone called TSH (Thyroxine-Stimulating hormone).The TSH tells the thyroid gland how much thyroid hormone it should make. If the levels of thyroid hormone in the blood are low, then the TSH will stimulate the thyroid gland to produce more Thyroid hormone.
9. Hypothalamus disorders: This is an organ in the brain. This produces a hormone called TRH (Thyrotropin Releasing Hormone) which acts on the Pituitary gland to secrete TSH. So any disorder of Pituitary gland will indirectly effect the production and secretion of Thyroid hormones. These are very rare disorders.
10. Congenital thyroid defects: Some babies are born with thyroid problems. This is due to the thyroid not being developed normally during pregnancy. Sometimes the thyroid gland does not function normal. This can be identified by screening for thyroid disorders in the first week after delivery. This is usually by a blood test using a small drop of blood from the baby’s heel.

Who are at risk of developing Hypothyroidism?

1. Women have a higher risk of suffering from hypothyroidism than men.
2. Older people are at increased risk.
3. People suffering from other autoimmune diseases like Coeliac disease, Type-1 Diabetes Mellitus, Vitiligo, Pernicious anemia, Multiple sclerosis, Rheumatoid arthritis, Addison’s disease etc.
4. People with psychiatric conditions such as bipolar disorder
5. People with Chromosomal abnormalities like Down syndrome, Turners syndrome also have a high risk of suffering from hypothyroidism.

How to diagnose hypothyroidism?

Blood tests:

1. TSH: This hormone is made in the pituitary gland and it stimulates the thyroid gland to produce thyroxine. If the thyroxine levels are low in the blood, the pituitary gland produces and secretes more TSH into the blood to act on the thyroid gland to produce more thyroxine. A raised TSH level indicates hypothyroidism. Other tests are not usually necessary unless a rare cause of hypothyroidism.
2. T4: A low level of thyroxine indicates hypothyroidism.
3. T3: these levels are generally not needed to diagnose hypothyroidism
4. Anti-Thyroid peroxidase antibodies (anti-TPO antibodies) or Anti- thyroglobulin antibodies are present in 90-95% of patient with autoimmune thyroiditis.
5. Other blood tests include Creatinine Kinase, Serum Lipids, Complete blood picture etc.
6. Ultrasound of the neck is done if the patient presents with a thyroid swelling.

What is the treatment of hypothyroidism?

Overt hypothyroidism is treated by synthetic Thyroxin hormone which should be taken every day on an empty stomach at least 30 – 45 minutes before breakfast. The treatment is continued for the rest of the patient’s life. Regular thyroid function tests are done once every 8 weeks-12 weeks to adjust the dose of the thyroxine in the initial period of diagnosis. Once the thyroxine dose is stabilised, the tests can be done even once a year. This treatment is quite effective.

Sub-clinical hypothyroidism is only treated if the patient is a woman and is contemplating pregnancy, in patients with symptoms or if the TSH is quite high.

What are the side-effects of thyroxine medication?

There are few side effects if any. Most people tolerate these medications quite well. An important consideration before starting medication is to check if the patient has chest pain/angina. These people are started on the least available dose. If these patients are started on a higher dose they notice a worsening of their angina pains.

Side effects mainly occur if the thyroxine dose is high which leads to hyperthyroidism. The symptoms of this could be palpitations 9increased heart beat), weight loss, profuse sweating, anxiety, irritability etc.

There are some tablets which increase with thyroxine tablets. These include carbamazepine, iron supplements, calcium supplements, rifampicin, phenytoin, warfarin etc.

What are the complications of hypothyroidism?

If untreated hypothyroidism can lead to:

• heart problems like heart attack due to increased levels of bad cholesterol like LDL, or heart failure due to fluid retention
• obesity
• infertility
• joint pains
• depression
• A pregnant woman with hypothyroidism is at increased risk of giving birth to a baby with congenital hypothyroidism, also known as cretinism. Further, the woman may have pregnancy related complications like pre-eclampsia, premature delivery, low birth weight baby, anemia, post-partum haemorrhage (bleeding after delivery) etc.
• Myxoedema is another complication where the patient has extremely low levels of thyroid hormone. The body temperature drops drastically making the person lose consciousness or go into a coma. If you wish to discuss about any specific problem, you can consult an Endocrinologist.