The thyroid gland is a butterfly-shaped gland that weighs about 15-20 grams and is located in the front of the lower neck between Adam’s apple and the breastbone. 

The thyroid gland secretes and produces triiodothyronine (T3) and thyroxine (T4) hormones. These hormones affect all aspects of metabolism, which is the pace at which your body processes food to make energy and heat.

They also influence the control of vital functions, such as body temperature and heart rate. The thyroid gland also needs adequate amounts of dietary iodine to be able to produce T4 and T3.

However, thyroiditis is the swelling and inflammation of the thyroid gland, which can lead to underproduction or overproduction of thyroid hormone.

There are three phases that thyroiditis comprises of: 

1. Thyrotoxic phase: This means that the thyroid is too inflamed and it releases too many hormones. 
2. Hypothyroid phase: Post the excess secretion of thyroid hormones, the thyroid does not have enough hormones to release. This leads to a lack of hormones or hypothyroidism.
3. Euthyroid phase: During this phase, the thyroid hormone levels are normal. This phase may either come after the thyrotoxic phase before going to the hypothyroid phase, or it may come at the end after the thyroid gland has recovered from the inflammation and is able to maintain a normal hormone level.

Cause of Thyroiditis: 

Thyroiditis can be caused by several agents that result in inflammation and damage to the thyroid cells, leading to thyroiditis. 

Some of the agents include antibodies, drugs, organisms (viruses and bacteria), and sometimes drugs such as interferon, amiodarone, and radiation.

Thyroiditis may also be an autoimmune disease and may sometimes be a reaction or a side effect of a certain drug.

Types of Thyroiditis:

1. Hashimoto’s thyroiditis (chronic lymphocytic thyroiditis): 

This is a common autoimmune disease caused by anti-thyroid antibodies. This kind of thyroiditis is diagnosed five times more in women than men. This disease occurs when the immune system mistakenly attacks and slowly destroys the thyroid gland and its ability to produce hormones in the body. The symptoms of Hashimoto’s thyroiditis are similar to hypothyroidism, such as fatigue, weight gain, constipation, and dry skin. Hashimoto’s thyroiditis usually leads to hypothyroidism, in which the treatment of thyroid hormone replacement is needed.

2. Silent (Painless) Thyroiditis:

This is another autoimmune disease that is caused by anti-thyroid antibodies. It is also common in women and the next common cause after Hashimoto’s thyroiditis.

3. Postpartum thyroiditis:

This is an autoimmune condition that occurs when a woman’s thyroid gland becomes inflamed after having a baby. This condition affects a small percentage of pregnant women (about 3 in 100). This may first result in the thyroid being overactive. But in time, it may also lead to an underactive thyroid. For instance, it can lead to symptoms of hyperthyroidism after 1 to 3 months of delivery, and symptoms of hypothyroidism begin about 4 to 8 months after delivery. 

4. Acute thyroiditis: 

This is a rare infection of the thyroid gland. The infection is painful and is associated with a fever, which progresses rapidly. The acute thyroiditis can affect children and adults, but it is more prevalent among children. Some of the symptoms include pain in the throat, mild illness, swelling of the thyroid gland, and in some cases, symptoms of hypothyroidism or hyperthyroidism.

5. Drug-induced thyroiditis:

A condition that is caused by the use of drugs such as amiodarone, interferons, lithium, and cytokines. However, this occurs in a small fraction of patients using the offending drugs, hence is not common to the normal population.

6. Radiation-induced thyroiditis:

This is a condition caused by external radiation, which is usually used as a medical treatment for certain cancers, or by radioactive iodine, which is used to treat hyperthyroidism. It may lead to symptoms of hypothyroidism or hyperthyroidism. 

Symptoms of Thyroiditis:

The symptoms of thyroiditis depend on the type and phase of thyroiditis.

During the hyperthyroid phase, common symptoms are:

• Anxiety
• Insomnia
• Rapid heart rate
• Weight loss
• Fatigue
• Heat intolerance
• Tremors
• Irritability

During the hypothyroid phase, common symptoms are:

• Fatigue
• Weight gain
• Constipation
• Depression
• Dry skin
• Lack of focus
• Poor exercise tolerance

Diagnosis of Thyroiditis:

The doctor may order blood tests to diagnose thyroiditis and determine what type you have. The blood tests are helpful in measuring the levels of thyroid hormone in your blood to detect whether there is an excess or a deficiency of the thyroid hormones.

In some cases, the doctor may decide upon a radioactive iodine uptake test that measures your thyroid’s ability to absorb iodine, a mineral that is needed to produce thyroid hormone. Early diagnosis and treatment of thyroiditis is crucial. Doctors may order one or more blood tests to check thyroid function. Contact your doctor if you’re experiencing any of these symptoms as soon as possible.