Thyroid Gland Diseases - Symptoms, Risk factors and Treatment

The thyroid gland is a butterfly-shaped organ located in front of the neck, wrapped around the windpipe. It is responsible for producing thyroid hormones, which play an important role in the body’s metabolism.

What hormones does the thyroid gland produce?

The thyroid gland produces two hormones, commonly known as T3 and T4. T3 and T4 are also known as triiodothyronine and thyroxine, respectively. The thyroid hormones utilize iodine. The T3 hormone contains three iodine atoms, and the T4 hormone contains four iodine atoms. Most of the T4 is converted to T3, which is the active form. 

The thyroid gland itself is under control of a hormone called TSH (thyroid-stimulating hormone ), produced by the pituitary gland located in the skull.

The thyroid hormones have their effect on almost every organ and cell of the body. Their primary function is to increase metabolism and energy consumption. Metabolism is when your body uses energy molecules such as carbohydrates, proteins, and fats along with oxygen to make ATP, a molecule by which our cells use energy.

What are thyroid diseases:

Thyroid diseases are conditions in which the thyroid gland is unable to function properly. There is a certain amount of thyroid hormone required by the body. In some conditions,  the thyroid gland produces too little (hypothyroidism) or too much (hyperthyroidism) of the thyroid hormone, both of which have adverse effects on the human body. 

The common diseases involving the thyroid are:

Hyperthyroidism:

In this condition, the thyroid gland becomes overactive and produces too much thyroid hormone. It results in increased metabolism. The symptoms of hyperthyroidism include:

• Restlessness
• Fast heart rate
• Irritability 
• Feeling hot
• Increased perspiration
• Anxiety 
• Insomnia
• Fatigue
• Brittle hair and nails
• Unintentional weight loss
• Protruding of eyes (Graves disease)

Hyperthyroidism can be caused by Graves’ disease, goiter, thyroid nodules, or thyroiditis.

When associated with goiter, symptoms of hyperthyroidism may be associated with an enlarged thyroid gland.

Hypothyroidism:

In hypothyroidism, the thyroid gland becomes underactive and produces little amounts of thyroid hormone than the amount the body requires. The metabolism becomes slow. The symptoms of hypothyroidism include:

• Tiredness and fatigue
• Dry skin
• Sensitivity to cold weather
• Constipation
• Depression
• Lethargy
• Memory problems
• Confusion
• Weight gain
• Slow heart rate

Conditions that are associated with hyper or hypothyroidism:

Graves disease:

Graves disease is named after  Dr. Robert James Graves, when he described this disease in 1835. It is a cause of hyperthyroidism. Graves disease is an autoimmune disease in which an antibody forms and stimulates the thyroid gland to produce more and more thyroid hormones. It shows symptoms of hyperthyroidism as discussed above, along with exophthalmos-bulging out of eyes and goiter-enlargement of the thyroid gland.  

Plummer disease ( Toxic solitary or multinodular goiter) :

It is a disease in which there is a problem with your genes. The genes for TSH receptors get mutated, continuously activating it. Recall that TSH is a hormone produced by the pituitary, as described above. It attaches to the TSH receptor to bring about its function. When the genes for TSH receptors are mutated, it results in its overactivation regardless of TSH levels, resulting in excess production of thyroid hormone.

Thyroiditis: 

There are different types of thyroiditis such as Hashimoto thyroiditis, subacute granulomatous thyroiditis, and silent lymphocytic thyroiditis. Thyroiditis means inflammation of the thyroid gland. In thyroiditis, the body’s immune system attacks the thyroid gland. The thyroid gland contains thyroid hormone in stored form (thyroid follicles). When the immune system attacks the thyroid gland, the follicles get damaged resulting in an increased release of pre-stored thyroid hormone, causing transient hyperthyroidism, followed by hypothyroidism. 

Thyroid nodules:

Thyroid nodules are growths in the thyroid gland which may be solid or filled with fluid. They can be associated with hypothyroidism ( as in associated with Hashimoto's thyroiditis) or hyperthyroidism (if the nodules produce thyroid hormone), and can show different symptoms respectively. If the nodules enlarge in size, the size of the thyroid gland may enlarge causing additional symptoms like hoarseness of voice, pain, trouble in swallowing or breathing.

Thyroid cancer:

It is the cancer of the thyroid gland, which shows symptoms of hyperthyroidism. It can occur due to gene mutations. Additional symptoms of thyroid cancer include:

• Difficulty breathing 
• Difficulty swallowing
• Hoarseness of voice
• Enlarged lymph nodes in the neck.

Goiter:

Goiter is an enlargement or swelling of the thyroid gland. It is usually harmless but can also be associated with diseases described above and can cause hyper or hypothyroidism. It is not a disease in itself, but rather indicates towards a disease. When a goiter is not associated with cancer or abnormal functioning of the thyroid gland, it is known as a Nontoxic goiter.

Diagnosis of thyroid diseases:

Thyroid diseases are primarily diagnosed by checking the levels of thyroid hormones that involve:

• T3
• T4
• TSH

Other than that, your doctor may suggest other tests such as a Radioiodine scan, MRI, CT scan, PET scan, or a thyroid biopsy to make a definite diagnosis.

Treatment of thyroid diseases:

The treatment of thyroid diseases depends upon the disease. It may involve medications, surgery.

CONCLUSION:

The thyroid gland plays a vital role in the body's normal functioning. Many diseases can affect the thyroid gland, and early detection and treatment of the disorder are of paramount importance. If you experience any symptoms of hyperthyroidism or hypothyroidism, it is highly recommended to see your healthcare provider.