The thyroid gland is an organ of the endocrine system of the body, the endocrine gland (from gr. Endo – inside, krino – highlight). The thyroid gland is a kind of “plant” for the production of special chemicals – hormones. Hormones enter directly into the blood due to the developed network of blood vessels that densely braid the organ. Despite its miniature size (normal organ volume in women is less than 18 ml and in men less than 25 ml), the gland controls the work of almost all of our organs. The most important purpose of thyroid hormones is to maintain normal metabolism in the body.  

Thyroxin and triiodothyronine (T4 and T3) are formed in the thyroid gland. Each of the hormones consists of a protein residue and iodine. It is through iodine that the action of thyroid hormones on the cells and tissues of the body is carried out. No iodine – no hormone!

There are three “hormonal” conditions of the thyroid gland – euthyroidism (normal function of the gland), hyperthyroidism or thyrotoxicosis (increased organ function, the amount of hormones in the blood is above normal) and hypothyroidism (decreased function of the gland).

Symptoms of thyroid disease are very diverse and can be completely opposite. It depends on the violation that occurred in the body.

Diseases of the thyroid gland caused by thyrotoxicosis, and their symptoms.

• Graves’ disease (Bazedov’s disease, diffuse toxic goiter);
• Multinodular toxic goiter;
• Functional autonomy of the thyroid gland (toxic adenoma);
• Thyroiditis: acute, subacute, painless and postpartum, hyperthyroid phase of autoimmune thyroiditis;

All of these diseases are united by thyrotoxicosis syndrome – a condition caused by an increase in the amount of thyroxine and / or triiodothyronine in the blood. Due to an excess of thyroid hormones in the body, metabolism is accelerated. An accelerated metabolism leads to the symptoms and complaints that accompany this condition.  

Classical (general) symptoms of thyrotoxicosis:

• palpitations, heart rhythm disturbances;
• arterial hypertension;
• trembling in the arms and body;
• insomnia;
• excessive sweating;
• impaired concentration of attention;
• irritability / emotional lability, tearfulness;
• weight loss with increased appetite;
• poor heat tolerance;
• shortness of breath with little physical exertion;
• fatigue, muscle weakness;
• frequent unformed stools;
• menstrual irregularities, infertility;
• brittle nails, hair loss.

For each disease, the causes of thyrotoxicosis are different.

In Graves’ disease, the cause of the increased work of our miniature organ is an autoimmune disease. In this disease, “your” cells and organs are recognized by the immune system as foreign, and it negatively affects them, damages, destroys. In this case, such aggression is aimed at the thyroid gland. Elements of the immune system (antibodies) cause increased production of hormones in the body. Over time, the thyroid gland increases in size, a person may experience discomfort in the neck, impaired swallowing, and a change in voice. With this disease, the soft tissues of the eye and the optic nerve can be damaged, in which case eye symptoms occur. Thus, in addition to the classic symptoms of thyrotoxicosis, with Graves disease can be:   

• discomfort in the neck;
• violation of swallowing, especially solid foods;
• hoarseness of voice;
• visually noticeable enlargement of the thyroid gland;
• eye symptoms:

1. “Bulging” eyes, “bags” under the eyes, redness and swelling of the conjunctiva, “squint”, swelling around the eyes, “not closing” eyelids;
2. a feeling of “sand” in the eyes, photophobia, decreased visual acuity;
3. painful feeling pressure behind or in front of the eyes, pain and double vision;

In toxic adenoma (TA) and multinodular toxic goiter (MTZ) , excessive production of thyroid hormones occurs by nodular thyroid formations. Such nodes secrete hormones uncontrollably and in large quantities. More often, the disease occurs in an older age group. Classical symptoms of thyrotoxicosis may not be pronounced, but complaints about: 

• heart rhythm disturbance;
• weight loss;
• weakness, decreased performance, and increased fatigue.

With a large node size, the following may occur:

• discomfort in the neck, a sensation of “coma” in the throat;
• violation of swallowing, mainly solid food.

Acute and subacute thyroiditis are inflammatory diseases of the thyroid gland. In acute thyroiditis, the cause of inflammation is bacterial, in subacute – a viral infection. The thyroid gland itself is not disturbed, and the increase in T4 and T3 in the blood is caused by the destruction of the thyroid cells. The classic symptoms of thyrotoxicosis in both forms of thyroiditis may be present in an erased form. Most often, with acute thyroiditis, patients complain of:   

• acute onset of the disease;
• sudden neck pain;
• swelling and redness of the front of the neck
• fever – fever up to 40 * C;
• chills;
• hoarseness of voice, violation of swallowing;
• severe weakness, fatigue, lethargy.

In subacute thyroiditis, the following symptoms prevail:

• the disease develops 2-8 weeks after a viral infection;
• acute or gradual increase in pain in the throat and front surface of the neck;
• pain in the neck gives in the lower jaw, ear, head;
• pain intensifies with coughing and turning the head;
• increase in body temperature to 38 * C;
• severe weakness, lethargy, fatigue;
• muscle pain, joints;
• sweating, trembling in the body, palpitations.

Painless and postpartum thyroiditis – these diseases are often combined and are called asymptomatic thyroiditis. It is more common in women, often during the first year after childbirth. The cause of the disease is a temporary change in the immune system. In this case, the period of thyrotoxicosis is short, from several weeks to 3-4 months. After the thyrotoxicosis phase, a short phase of hypothyroidism (a decrease in thyroid function) may occur, followed by a complete restoration of the function of the organ. Symptoms of thyrotoxicosis are minor, or none at all.    

Autoimmune thyroiditis is an inflammation of the thyroid gland caused by an autoimmune disease. The disease can occur with a change in the phases of thyrotoxicosis, euthyroidism (normal state of the thyroid gland) and hypothyroidism. Thus, with this disease, you can see both the classic symptoms of thyrotoxicosis and hypothyroidism, which will be described later. 

Diseases of the thyroid gland due to hypothyroidism and their symptoms.

• Primary hypothyroidism;
• Secondary and tertiary hypothyroidism;
• Transient (temporary) hypothyroidism.

Hypothyroidism is a syndrome caused by a decrease in the amount of thyroxine and / or triiodothyronine in the blood, or the loss of the action of thyroid hormones on organs and tissues. In this case, the metabolism slows down, which leads to the typical symptoms of this disease:  

• fatigue, weakness, drowsiness, lethargy, memory loss;
• pallor of the skin, icteric shade of the skin;
• poor cold tolerance, decreased body temperature;
• Depression
• weight gain, decreased appetite;
• swelling of the face and limbs;
• joint pain
• constipation
• dry skin
• hair loss, often nasal baldness;
• menstrual irregularities, infertility;
• difficulty, slurred speech with swelling of the tongue, hoarseness of voice;
• hearing loss and difficulty in nasal breathing.

Any of the forms of hypothyroidism can occur both in mild (subclinical hypothyroidism) and in a more severe form (manifest hypothyroidism). Depending on this, the symptoms will be more or less pronounced.

Primary hypothyroidism – with this disease, the thyroid gland is not able to produce the right amount of hormones. The most common cause is chronic autoimmune thyroiditis (HAIT) , which was mentioned earlier. The disease progresses slowly, and in the early stages there is no decrease in thyroid function. However, over time, when the number of “working” cells in the thyroid gland becomes smaller, it can no longer cope with its function, and hypothyroidism sets in.  

In addition to HAIT, primary hypothyroidism can occur after surgical treatment of the thyroid gland (removal of all or part of the gland), in the outcome of infectious and asymptomatic thyroiditis, overdose of certain drugs (amiodarone, thyreostatics, lithium preparations) and toxic substances, due to severe deficiency or excess iodine, as well as with congenital anomaly of the thyroid gland, when its volume is very small from birth.

With secondary and tertiary hypothyroidism, a violation occurs in the brain – the pituitary gland or hypothalamus. As mentioned earlier, the thyroid gland is controlled by the structures of the brain. If there is a violation in this management, the thyroid gland malfunctions. These forms of hypothyroidism are characterized by typical symptoms, as well as: 

• lack of obesity or even low body weight;
• swelling on the face and limbs;
• signs of heart failure;
• often combined with insufficiency of other endocrine glands.

Transient hypothyroidism is a temporary, transient hypothyroidism. It occurs with painless, postpartum, viral or bacterial thyroiditis; in patients with chronic inflammatory diseases; with some oncological diseases. After eliminating the cause of these diseases, hypothyroidism spontaneously “leaves”. Symptoms of temporary hypothyroidism are typical. Its duration is about 3-4 months. 

Volumetric formations in the thyroid gland, not leading to hormonal disorders:

1. Nodular (multinodular) euthyroid goiter.
2. Nodular colloid goiter;
3. Follicular neoplasia (follicular adenoma);
4. Thyroid cancer.

The term “euthyroid” means “normally functioning”. All volumetric thyroid formations, which will be discussed later, do not lead to a violation of the hormonal function of the thyroid gland, that is, the thyroid gland synthesizes thyroid hormones commensurate with the needs of the body.

Nodular goiter is a collective concept. It combines all the voluminous formations of the thyroid gland, which have a different nature, structure, type of growth, etc.  

As the name implies, in this disease of the thyroid gland in its structure reveals one, or several nodes. A nodule is an entity that is larger than 1 cm.

Complaints and symptoms:

• the disease is most often asymptomatic;
• dyspnea;
• violation of swallowing, especially solid foods;
• hoarseness of voice;
• feeling of pressure in the neck.

Nodular colloid goiter – the most common form of nodular goiter (more than 97%), is benign. This is a NON-TUMOR formation. This is the formation of ordinary, unchanged thyroid cells that have “grown”. Such a node will NEVER be cancer! With small nodes, there are no symptoms. Symptoms and complaints can occur with large nodes, with the proximity of nodes to the larynx, which is extremely rare. The growth of nodes is usually slow. 

Follicular adenoma is also a benign formation, but there is a risk that it can “develop” into cancer. Such nodes can grow both slowly and quickly enough. When the node acts on the trachea, esophagus, nerves, there is a violation of swallowing and speech. 

Thyroid cancer – unfortunately, with this disease there are no special symptoms and complaints. With small formations, they may not be, and with large ones, there may be a violation of swallowing and speech. But there is good news – mortality in thyroid cancer is extremely small – less than 1%.  

It is worth mentioning that if you have a node in the thyroid gland identified, it is 97% likely that it will be a harmless nodular colloid goiter that will not change either your health or your life prognosis. Therefore, one should not be scared if such a change is found in the organ.

Iodine deficiency diseases:

• Diffuse euthyroid goiter;
• Nodular (multinodular) euthyroid goiter;
• Nodular (multinodular) toxic goiter.

The cause of all these diseases is the insufficient consumption of iodine .. As mentioned earlier, the molecule of the thyroid hormones consists of a protein residue and iodine. In conditions of iodine deficiency, the thyroid gland “adapts” in such a way as to ensure sufficient production of hormones. Special growth factors are activated that cause an enlarged thyroid gland. A diffuse euthyroid goiter is formed , and over time, nodular formations (nodular or multinodular goiter) may occur . Some nodes due to tissue mutations can become hormonally active, that is, to synthesize hormones on their own – a nodular (multinodular) toxic goiter is formed . Such nodes secrete hormones uncontrollably and in large quantities.    

Complaints and symptoms:

• enlargement of the thyroid gland, a cosmetic defect is possible;
• with a large size of the gland or large nodes – shortness of breath, violation of swallowing, especially of solid food, hoarseness of the voice, a feeling of pressure in the neck.
• With nodular toxic goiter – the classic symptoms of thyrotoxicosis (see above).

As can be seen from our review, the symptoms of thyroid disease are very diverse. Sometimes there is such a situation when a person goes to different doctors for several years – consults a neurologist, cardiologist, ENT doctor, gynecologist, receives treatment, and still feels bad. The thyroid gland is a unique organ that affects all the systems of our body, and we must not forget about it! If you notice the symptoms indicated in the article, or you have had thyroid disease in your family, this is an occasion to consult a doctor. With timely diagnosis and treatment, even a formidable disease – thyroid cancer – can be completely cured. There is also no doubt about the need to treat hypothyroidism and thyrotoxicosis – the earlier the cause of the condition is identified and treatment is started, the lower the risk of formidable complications and long-term consequences.

Take care of yourself and be healthy!