Hypothyroidism

The symptoms of hypothyroidism vary with age and can be subtle, especially at first. They appear gradually and differ in children, adolescents and adults.

In adults

Adults with hypothyroidism generally experience constant fatigue, unexplained weight gain with no change in eating habits, intolerance to cold, and skin and hair changes (dry skin, brittle hair). Symptoms may also include cognitive disorders such as difficulty concentrating or memory loss. Hypothyroidism can also lead to a slower heart rate.

Adolescents

Adolescents may experience delayed puberty and chronic fatigue. Weight gain without apparent cause, accompanied by mood disorders such as depression or anxiety, is common. Some teenagers also experience difficulties at school due to concentration problems.

In children

In infants and young children, hypothyroidism can lead to delayed growth and development. Untreated childhood hypothyroidism can also affect intellectual development.

These symptoms, often unspecific, may be confused with other conditions, which can delay diagnosis.

Hypothyroidism can result from a variety of causes, including autoimmune pathologies, medical interventions or deficiencies. There are also several forms of hypothyroidism that differ in origin:

Primary hypothyroidism

This is the most common form, where the problem arises directly from the thyroid itself. Most often caused by Hashimoto's thyroiditis, an autoimmune disease in which the immune system attacks the thyroid gland. Other causes include thyroid surgery, radiotherapy to the neck or iodine deficiency. In these cases, the thyroid does not produce enough hormones, despite stimulation by TSH (thyroid stimulating hormone).

Secondary hypothyroidism

In this form, the problem lies with the pituitary gland, located at the base of the brain. The pituitary gland is responsible for producing TSH, which stimulates the thyroid gland to produce its hormones. If the pituitary gland is defective due to tumour, trauma or radiotherapy, it does not produce enough TSH, resulting in hypothyroidism. This type is rarer than primary hypothyroidism.

Tertiary hypothyroidism

Even rarer, this form occurs when the brain (specifically the hypothalamus) doesn't produce enough TRH (thyrotropic hormone), the hormone that controls TSH release from the pituitary gland. This deficiency leads to a drop in thyroid hormone production.

Subclinical hypothyroidism

This is a milder form of hypothyroidism where TSH levels are slightly elevated, but thyroid hormones (T3 and T4) are still within normal limits. This type of hypothyroidism may evolve or disappear spontaneously.

Some people are at greater risk of developing hypothyroidism:

• Women: Women, especially over 60, are more often affected.
• Family history: A genetic link may exist, increasing the risk if a close relative is affected.
• Pregnancy: Some women develop hypothyroidism after childbirth.
• Radiotherapy or neck surgery: Those who have undergone surgery in this area are at increased risk.

Diagnosis is based primarily on the patient's history and clinical examination, leading to further investigations. Blood tests measuring TSH (thyroid-stimulating hormone) and free T4 (thyroxine) levels are then carried out. An elevated TSH accompanied by a low T4 generally indicates hypothyroidism. Other tests, such as ultrasound, may be used to examine the structure of the thyroid. In some cases, thyroid scintigraphy may be performed to assess the activity of the gland.

The standard treatment for hypothyroidism is hormone replacement therapy, often in the form of levothyroxine (synthetic T4). This treatment aims to normalize thyroid hormone levels and relieve symptoms. It requires long-term follow-up to adjust treatment dosage as health status fluctuates.

If left untreated, hypothyroidism can lead to serious complications:

• Goiter: Enlarged thyroid due to excessive TSH stimulation.
• Cardiovascular problems: Untreated hypothyroidism can increase the risk of heart disease.
• Myxedema: A rare and serious form of hypothyroidism that can lead to a potentially fatal coma.

There is no direct way to prevent hypothyroidism, but certain measures can help:
Monitoring risk factors: People at risk should regularly monitor their thyroid function through check-ups.
Iodine supplementation: In regions where iodine deficiency is common, the addition of iodine to the diet is essential for proper thyroid function.

It is recommended to consult a doctor if you experience symptoms such as:

• Persistent fatigue, despite adequate rest.
• Unexplained weight gain.
• Intolerance to cold.

Medical follow-up is also necessary for people undergoing treatment, to ensure that levothyroxine dosage is appropriate.

Hôpital de La Tour offers a comprehensive, personalized approach to thyroid disorders, particularly hypothyroidism. In the vast majority of cases, the diagnosis is made by the attending physician, on the basis of a clinical examination and biological tests. If necessary, the GP can refer the patient to an endocrinologist or other specialist for further investigations or specific follow-up.

For patients already treated at Hôpital de La Tour, or who do not have their own GP, the Centre de médecine générale de l'Hôpital de La Tour offers access to a team of general internists. This center facilitates the coordination of care within the hospital, in close collaboration with other specialists, in a spirit of continuity and responsiveness

1. What is hypothyroidism?
Hypothyroidism is a condition in which the thyroid gland does not produce enough hormones to regulate metabolism properly.

2. What are the main symptoms of hypothyroidism?
Symptoms include fatigue, weight gain, cold intolerance and depression.

3. What causes hypothyroidism?
The main causes are Hashimoto's thyroiditis, thyroid surgery and radiation.

4. How is it diagnosed?
It is diagnosed by a blood test measuring TSH and T4 levels.

5. Is hypothyroidism curable?
No, but it can be effectively treated with hormone replacement therapy.