Hypothyroidism: symptoms, congenital, is it curable, fattening?

The thyroid is a gland located in the neck, in the region popularly known as Adam’s apple or gogó. It is very common to be compared to the shape of a butterfly or that of a shield.

Knowing more about this essential part of the body is important to be able to identify when everything is not going the way it should.

When there is a disorder in this gland, several functions of the organism are compromised, as the levels of secreted hormones can vary.

Thus, the correct functioning of vital organs, growth and development during childhood and adolescence, weight, mood, menstrual cycle and various other body functions are impaired.

One of the variations that can occur is hypothyroidism, a disease in which the thyroid is unable to produce and release hormones in the ideal amount.

In the following text, we explain how this happens and what the causes are. Check out!


What is hypothyroidism?

Hypothyroidism, or underactive thyroid, is a disease in which the thyroid, one of the body’s main glands, does not function properly. Among the changes that affect the gland, this is the most common.

In this condition, it ends up producing, in a reduced way, the hormones T3 and T4 (triiodothyronine and thyroxine), important in several functions.

With insufficient production, it is as if the organism is running on less fuel, functioning more slowly. This slowness ends up being quite harmful to health, as it compromises the way vital organs work, slowing heart rate, for example.

This response from the body is an attempt to save energy, as it understands that there are not enough resources (hormones) to maintain all activities normally.

Thus, hypothyroidism can leave the patient with extreme tiredness , drowsiness, joint and muscle pain, raise cholesterol levels and even increase the risk of diseases such as depression .

It is also a disease associated with gaining or losing weight due to fluid retention and metabolism, which slows down, being one of the perceptible symptoms of the condition.

However, what causes hypothyroidism varies widely. It can occur because it is a congenital, autoimmune disease, medication, iodine deficiency and even due to pregnancy.

In general, it is a more common disease among women, people over 60 years old and in those who have a family history of the disease. However, it can also manifest itself in children and adolescents.

In this age group, the most common cause of hypothyroidism is Hashimoto’s syndrome, an autoimmune disease in which the body itself attacks thyroid cells.

One of the ways to investigate the disease in childhood is through the heel prick test , performed in the first days of the baby’s life. In this way, it is possible to start treatment and reduce the risk of complications.

The diagnosis of hypothyroidism is simple, usually based on a measurement of thyroid hormones in the blood. A sample is collected to measure levels of TSH , a hormone that controls the thyroid.

From it, it is possible to confirm the disease and evaluate the levels of T3 and T4. Treatment is done with hormone replacement.

In ICD-10, the International Code of Diseases, hypothyroidism is found by different codes, according to the cause, which are as follows:

  • E03 : Other hypothyroidism;
  • E03.0 : Congenital hypothyroidism with diffuse goiter;
  • E03.1 : Congenital hypothyroidism without goiter;
  • E03.2 : Hypothyroidism due to drugs and other exogenous substances;
  • E03.3 : Post-infectious hypothyroidism;
  • E03.8 : Other specified hypothyroidism;
  • E03.9 : Hypothyroidism, unspecified.

How does the thyroid work?

The thyroid is a gland that governs various functions in the body, like a kind of conductor in our body. As one of the largest glands, weighing between 15g to 25g, it interferes with the functioning of all systems.

With the production of the hormones T3 and T4, triiodothyronine and thyroxine, it guarantees the correct functioning of the organs and various processes of the organism.

However, for it to work properly, it needs a stimulus by the pituitary gland, another gland in our body that is located in the brain region.

The pituitary gland is responsible for sending this stimulus through the release of a hormone called TSH.

If there is any variation, regardless of the triggering factor, which makes the thyroid work slower, the pituitary understands that more TSH needs to be produced.

The higher dosage of the hormone in the blood is a sign that the thyroid is not working the way it should, which is characterized as hypothyroidism.

What is the difference between hypothyroidism and hyperthyroidism?

Hypothyroidism and hyperthyroidism are disorders that affect the functioning of the thyroid, being different diseases because they cause opposite effects. While in hypothyroidism there is a low secretion of hormones, in hyperthyroidism there is an excess release.

In hyperthyroidism, the patient has an overactive thyroid, which makes the metabolism much faster, as it provides a much higher amount of hormones than the body needs.

With this activity higher than expected, the disease can cause an increase in the size of the gland, causing a swelling in the neck region.

The symptoms that patients with hyperthyroidism may have, as a consequence of these high hormonal doses, involve difficulty sleeping, rapid heartbeat, agitation, excess energy even with tiredness, excessive sweating, heat, irregular menstrual cycle and hair loss .

The most common cause of hyperthyroidism is an autoimmune disease called Graves’ disease.

The main difference, therefore, is in the doses of hormones secreted by the thyroid, the causes and the symptoms. Both conditions must be diagnosed and treated by an endocrinologist.

Types of hypothyroidism

In addition to being divided by causes, hypothyroidism is also classified according to the way that the glands secrete hormones, which are of the primary, secondary and tertiary type.

  • Primary : it is hypothyroidism that occurs due to thyroid failure;
  • Secondary : it is a consequence of some dysfunction in the pituitary gland;
  • Tertiary : it happens due to some deficiency in the pituitary gland and lack of HRT, that is, hormone replacement therapy.

In the case of a laboratory evaluation, the disease can be further divided into classic and subclinical hypothyroidism.


In classic hypothyroidism, the patient has a thyroid that is unable to produce enough hormones for the body to function properly. That way, when you have a blood test, you will have low levels of the hormone T4 and high levels of TSH.

High TSH levels represent an attempt by the pituitary gland to get the thyroid to work properly, but the secreted doses don’t do it.

In these cases, it is common for the disease to be progressive. Thus, over time, if left untreated, the risk of complications is greater.


In subclinical hypothyroidism, also called pre-hypothyroidism, the patient has normal levels of thyroid hormones (T3 and T4), but high levels of TSH.

In these cases, the thyroid is no longer in perfect condition, but it is still able to produce enough hormones due to high TSH levels.


It is hypothyroidism in which the person is already born with the dysfunction. It can occur in the child due to thyroid malformation during pregnancy, problems with TSH synthesis and excess or deficiency of iodine, for example.

This type is dangerous, because if not diagnosed and treated early it can cause damage to the brain functions of the child.


Hypothyroidism is a disease caused by low production and secretion of thyroid hormones, such as T3 (triiodothyronine) and T4 (thyroxine). There are several factors that can trigger the condition, such as surgeries, medications, autoimmune diseases , pregnancy and malformations in the intrauterine (congenital) period.

Better understand the main factors that cause this disease are:

Thyroid gland surgery

When some part of the thyroid is compromised during a surgical procedure, it is possible that there is some damage in the production and secretion of hormones.

In these cases, it is understood that surgery on the thyroid gland can cause hypothyroidism, which requires hormone replacement treatment.

Pituitary problems

The pituitary gland is the gland responsible for sending the correct signals for the thyroid to function properly, which happens through the release of thyroid stimulating hormones (TSH).

When a disorder affects this gland, the endocrine system is damaged as a whole.

The presence of autoimmune diseases in the pituitary gland, the appearance of tumors and brain damage can cause hypothyroidism.


Radiotherapy is a treatment commonly indicated for patients with some type of cancer . It is done through the use of radiation to prevent cancer cells from spreading or to destroy a tumor.

Despite being a therapy that helps many patients, it has many side effects, being possible the development of hypothyroidism.

Iodine deficiency

Iodine is an essential mineral for the body, being essential for the production of thyroid hormones. Therefore, its deficiency can cause hypothyroidism.

In Brazil, fortunately, it is not common for the disease to be caused by iodine deficiency, since table salt already contains the mineral.

In addition to salt, iodine can also be consumed by eating seafood.

Congenital disease

Some people have the disease due to some thyroid malformation during pregnancy. Thus, they are born with this damage in the production of hormones. These conditions are called congenital hypothyroidism.

The investigation of the disease in these children can be done through the heel prick test. It can happen that they do not show any symptoms after birth, but if the disease is not treated, they can have serious complications in the future.


Pregnancy does not necessarily cause thyroid dysfunction, but during pregnancy the chances of hypothyroidism developing are greater, because the woman’s body is more vulnerable to hormonal changes.

There may also be a production of antibodies that attack the thyroid and impair the release of hormones.

The condition, when left untreated, can lead to premature birth and increased blood pressure in the mother. In addition, it can also affect the baby’s development, which may have brain damage due to a lack of thyroid hormones.

Autoimmune diseases

In autoimmune diseases, the immune system itself attacks healthy body tissues, which can also affect the thyroid. In such cases, patients may also develop hypothyroidism.

Inadequate treatment for hyperthyroidism

Hyperthyroidism is the condition in which the thyroid produces excess hormones, overloading the body’s functions by high doses of hormones.

In these cases, treatment needs to be done with drugs that control this accelerated production, so that the patient has a remission of symptoms.

However, when this treatment is not done correctly, the situation can be reversed, causing an unwanted thyroid inhibition and causing hypothyroidism.

Hashimoto syndrome

Hashimoto’s syndrome is an autoimmune disease in which antibodies produced attack the thyroid, being one of the most common causes of hypothyroidism.

In the disease, antibodies cause the destruction of the gland or the reduction of its activity, which can lead to hypothyroidism due to a deficiency in the production of hormones T3 and T4.


Some drugs that have lithium in their composition, such as those used to treat depression and bipolar disorder, can cause a change in the functioning of the thyroid.

The use can inhibit the secretion of thyroid hormones and increase the production of TSH. Therefore, patients using any medication with this substance should undergo routine examinations.

What are the risk factors?

Despite being a condition that can affect anyone, some should be more careful. Certain groups and factors are considered to be at risk for the onset of the disease. Are they:

  • Women who are pregnant or intend to become pregnant;
  • People who use drugs that interfere with thyroid function and hormone secretion;
  • Patients who are undergoing radiation therapy;
  • Patients with autoimmune disease;
  • People over 60;
  • People with a family history of autoimmune disease;
  • Patients who have already had thyroid surgery.

Women are also considered a risk group, as about 10% of those over 40 can develop a thyroid problem.

The risks increase even more with aging. From the age of 60, the chances of having some disorder in the gland will be 20% higher.

Does hypothyroidism get fat?

It is very common to relate hypothyroidism to weight gain, and it is recurrent that people who are overweight or have difficulty losing weight seek to investigate whether they have any changes in the thyroid.

So, understanding how the disease interferes with metabolism is one of the most important steps to understand this issue of extra pounds.

Those who have hypothyroidism suffer a loss in the action of the metabolism, which becomes slower. With this function compromised, it is normal to experience a variation in weight.

However, when we talk about this change, we are referring to the condition that has not yet been diagnosed and treated correctly.

Therefore, it is possible to say that hypothyroidism is fattening, but not to the point of being the only determining factor in an extravagant weight gain.

That is, with slow metabolism, the patient with hypothyroidism will not be able to burn calories in the same way as a person who has a functioning body.

However, with the diagnosis, correct medication and proper use of medicines, the body must return to normal functioning and weight as well.

From the treatment initiated and the success of hormone replacement, a persistent weight gain may be related to other factors, such as eating habits, frequency of physical activities or other clinical conditions.

Therefore, in order not to put on weight, the patient with hypothyroidism must follow the treatment prescribed by the doctor, maintain a healthy diet, sleep well, exercise and maintain a routine of visits to the endocrinologist.

Hypothyroidism in pregnancy

During pregnancy, the woman’s body undergoes several hormonal variations. In the case of thyroid hormones, production can increase up to 50% to meet the needs of the mother and baby.

However, in some cases, the woman’s body fails to produce enough hormones for her and the fetus, which poses risks to both their health. This is the hypothyroidism that can occur during pregnancy.

When the pregnant woman does not receive the diagnosis and treatment, the disease represents a serious risk to the baby’s health, which will also have a hormonal deficiency, since it is dependent on the mother’s hormone doses.

By not receiving them, especially during the first 3 months of pregnancy , the baby may have cognitive impairments, not developing speech well or presenting some type of intellectual disability.

Therefore, when planning the pregnancy, the woman must already investigate the disease, making tests for the measurement of TSH.

At the beginning of pregnancy it is also important to perform the exams again.

If any variation in dosages is diagnosed, the pregnant woman must correctly follow the medical prescription for hormone replacement, having medical monitoring during prenatal care.

When a woman develops hypothyroidism during pregnancy, it is possible that the condition will not return to normal after delivery. Thus, she will have to treat the disease for the rest of her life.

However, there are conditions in which the change is transient, since the thyroid ends up normalizing the levels of hormone production.

In any case, women should be instructed to perform periodic examinations to assess the functioning of the gland.

Read more: What is not normal during pregnancy?

What are the symptoms of hypothyroidism?

With the low release of thyroid hormones, many of our body’s activities are compromised. It is as if the body slows down because it does not have enough fuel.

However, symptoms do not always appear at the onset of the disease. In the initial phase, patients may be asymptomatic. One of the first signs that can appear is an increase in the size of the thyroid, which is not always visible.

The intensity and severity of symptoms depends on the degree of change in hormonal dosages. Because they are not specific, it is essential that people perform preventive exams to assess the functioning of the thyroid, which should be done with the monitoring of an endocrinologist.

Thus, the isolated symptoms do not characterize hypothyroidism. The patient with this disease usually has several of these manifestations, which needs to be confirmed with a laboratory diagnosis.

As the disease progresses, other symptoms appear. Are they:

  • Frio;
  • Dry skin, hair and nails;
  • Swelling in the eyes and face;
  • Loss of hair;
  • Joint pain;
  • Somnolence;
  • Ronco;
  • Slow growth;
  • Delayed puberty;
  • Liquid retention;
  • Variation in weight;
  • Cold;
  • Cramps;
  • High cholesterol;
  • Depression;
  • Pallor;
  • Slow heart rate;
  • Night cramps.

Understand a little better of the main symptoms:

Fatigue and weakness

The fatigue or constant tiredness is a major symptom of hypothyroidism.

It is a consequence of very low hormonal doses, which play a fundamental role in generating energy for the body. As a side effect, the patient feels slower and tired, mentally and physically.

Cardiovascular damage

The lack of thyroid hormones in the right amount causes damage to the heart and other vital organs because the body slows down and is unable to maintain the same physical effort as a healthy person.

In this way, the heart rate is compromised and the health of the heart is also affected by hypothyroidism because the disease can raise cholesterol levels.

Loss of hair

Even our hair depends on the hormones secreted by this gland.

Thus, when there is a variation in rates, as occurs in hypothyroidism, the patient may have excessive hair loss, in addition to a more dry, thin and brittle appearance of the hair.

Read more: Alopecia (hair loss): what is it, types, treatment, is it curable?

Weight variation

With hypothyroidism, metabolism slows down. Therefore, one of the symptoms of the disease is weight variation, as there is less energy expenditure and greater fluid retention.

In addition, the disease causes greater fatigue, which reduces the chances of the patient having an active physical exercise routine, which can lead the patient to put on weight more easily.

Irregular menstrual period

It is common for women to experience some variations in the menstrual period when hypothyroidism is not fully controlled.

This is due to the influence that hormones secreted by the thyroid have on the menstrual cycle. Thus, patients may experience variations in menstruation days and flow.

How is the diagnosis of hypothyroidism made?

The diagnosis is made by the general practitioner or endocrinologist, who analyzes the symptoms and requests tests to confirm the disease.

Some at-risk groups, such as older women and pregnant women, may be instructed to perform routine tests for prevention and early diagnosis.

Exame TSH

Normally, a blood test called a TSH test is required to analyze the dosage of thyroid hormone levels.

When TSH (thyroid stimulating hormone) is high and T4 hormones are low, hypothyroidism is confirmed.

In some cases of mild or initial (subclinical) hypothyroidism, TSH may be at higher levels, but T4 at normal levels. To confirm the diagnosis, in these cases, the doctor needs to consider the results of TSH.

Foot test

In newborn children, the disease is investigated through the heel prick test, a mandatory screening that must be carried out even in the first days of the baby’s life (between the 3rd and 5th day after delivery).

Is there a cure?

Unfortunately, no . Hypothyroidism is a chronic condition that requires the patient to have medical follow-up and treatment with hormone replacement throughout life.

In some cases, hormone replacement doses are gradually reduced, but they are still not considered to be cured.

The good news is that the disease can be fully controlled. However, interrupting treatment can cause symptoms to return.

Treatments: remedy for hypothyroidism

The main treatment for hypothyroidism is hormone replacement. After the diagnosis, the patient is instructed by the doctor to take pills for daily use so that these hormone levels are normalized.

The hormone used is levothyroxine , a synthetic version of tetraiodothyronine (T4). Among the options are Euthyrox , Levoid and Puran T4 .

The dose of hormone required for each patient is determined by the levels of TSH in the blood.

After indicating the medication, medical monitoring is also essential so that it is possible to assess how the patient’s organism is responding.

When they are above what is necessary, dosages can also cause dangerous side effects to health.

Some of the symptoms that can occur with high doses include insomnia , tremors, increased appetite and variations in heart rate.

Low doses can also compromise treatment, causing symptoms of hypothyroidism to persist. In general, when the treatment is properly addressed, the patient begins to improve within one to two weeks.

The medication used for the treatment is oral and should be taken daily in the morning, on an empty stomach. The ideal is to wait at least 30 minutes to have breakfast, so that the hormone can be absorbed by the body without interactions.


NEVER self-medicate or stop using a medication without first consulting a doctor. Only he will be able to tell which medication, dosage and duration of treatment is the most suitable for his specific case. The information contained on this site is only intended to inform, not in any way intended to replace the guidance of a specialist or serve as a recommendation for any type of treatment. Always follow the instructions on the package insert and, if symptoms persist, seek medical or pharmaceutical advice.

Why do I have to take the medicine on an empty stomach?

Levothyroxine should be ingested on an empty stomach, half an hour before breakfast, to prevent the food ingested from interfering with the absorption of the medication. It is a recommendation to ensure the effectiveness of hormone replacement.

It is also recommended that other drugs are not taken at the same time, being necessary to wait for up to one hour after the levothyroxine time.

Food: Do you have a hypothyroid diet?

There is no specific diet for patients with hypothyroidism, but there are some important recommendations for preventing thyroid health and functioning.

Therefore, patients with this disease should be careful with their diet. However, this does not mean that there is an established menu

The main precautions are:

Consume little salt

Salt, since it already has added iodine, should be consumed in small amounts, not only to preserve the thyroid, but also because it is a risk for the development of other health problems.

In relation to hypothyroidism, consumption of excess salt may end up aggravating conditions that are already being treated or not yet diagnosed, since the excess iodine interferes with the functioning of the metabolism.

Avoid goitrogenic foods

Some foods can cause goiter, a condition in which the thyroid has its size changed, so they should be consumed in moderation by those who have the disease or have a family history.

Among these foods are soy-based foods, turnip, cabbage and cabbage, for example. It is recommended that patients consume one to two times a week.

Consume good thyroid foods

There are foods that have nutrients beneficial to thyroid health and therefore should be part of the diet of those who have hypothyroidism.

They are the ones that have iodine, zinc, omega 3 and selenium. Some options are oysters, fish, seaweed, egg, beans , almonds, peanuts, meat, avocado etc.


Hypothyroidism is a disease that can be completely controlled with the use of hormone replacement drugs. Thus, patients with this diagnosis can lead a normal life.

However, when they are not diagnosed and treated, some complications can occur:

Impairments in physical and mental development

Congenital hypothyroidism, which develops in children even during the intrauterine period, when untreated, can cause damage to the baby’s central nervous system. In such cases, the child may have complications in mental and physical development.


Goiter is a condition characterized by an increase in the size of the thyroid, due to the constant stimulus for more hormones to be released.

This growth of the gland causes a swelling in the neck area, which causes difficulty in breathing and swallowing.


Myxedema is a skin complication caused by severe hypothyroidism. The patient in this condition has severe swelling in the face.


When thyroid hormone levels are low, women may experience difficulties during ovulation, with impaired fertility.

Damage to the functioning of the heart

Hypothyroidism, in addition to reducing the heart rate, can also raise cholesterol levels. For these reasons, when left untreated, it poses a serious health risk.

Is it possible to prevent?

In general, there is not much that can be done to prevent hypothyroidism, as some of the factors that cause the disease cannot be controlled, such as the appearance of autoimmune diseases and congenital hypothyroidism.

However, iodine deficiency hypothyroidism, however, is one of the cases that can be prevented with the help of supplements. In some countries, where the lack of this mineral is common, this preventive measure can be taken.

Mostly, iodine is added to table salt, which helps in preventing the disease. It is also present in seafood and in some types of fish, such as cod and mackerel.

However, it is necessary to be careful with the quantities. Approximately 150 micrograms of iodine is enough to maintain thyroid function.

In pregnancy, hypothyroidism cannot exactly be prevented, but early diagnosis is decisive to reduce the risk of complications for the pregnant woman and the baby. Therefore, it is important to carry out examinations and medical follow-up.

Hypothyroidism in dogs

Dogs, like humans, are susceptible to disorders of thyroid function. Thus, they may also have hypothyroidism.

Therefore, owners should pay attention to the signs related to the dogs’ behavior. With hypothyroidism, pets can exhibit sudden aggression, phobias and extreme shyness.

In addition to behavioral symptoms, dogs may have physical symptoms such as shedding, dermatitis, scaling and coat opacity. They may also experience excessive sleepiness, apathy and indisposition.

In the face of any of these changes, the dog should be taken to the veterinarian as soon as possible to receive a diagnosis. For this, a blood test must be done to assess the dosage of hormones.

The treatment of hypothyroidism in dogs is also done through hormone replacement, with oral tablets for daily use.

There are several causes of this disease in dogs and, unfortunately, there is also no form of prevention. Therefore, the best measure is to pay attention to the signs that the dog gives and take him frequently to the vet.

Performing preventive exams and checking the production of these hormones is essential to control the disease and avoid complications. Thus, those who suffer from thyroid disorders can lead a normal life, thanks to the drug treatment that ensures a control of thyroid production.

Now that you already know what hypothyroidism is, you know the symptoms and how the disease occurs, how about sharing this information with more people? Also, when was the last time you saw an endocrinologist? Thanks for reading!