Thyroid diseases: symptoms, causes and treatment

Hyperthyroidism occurs when the thyroid is overactive, producing too much hormone, particularly tri-iodothyronine (T3) and thyroxine (T4). This condition can develop in autoimmune disorders, when the immune system mistakenly attacks the thyroid, over-stimulating it.

The symptoms of hyperthyroidism can vary, but usually include:
• Weight loss;
• Rapid heart rate;
• Palpitations;
• Nervousness and irritability;
• Tremors and excessive perspiration;
• Fatigue and muscle weakness;
• Sensitivity to heat;
• Difficulty sleeping;
• Frequent bowel movements.

In this case, the thyroid is underactive, producing insufficient hormone levels, which can slow down the metabolism and compromise several biological processes. One of the most common causes of hypothyroidism is Hashimoto’s Thyroiditis, an autoimmune disorder that destroys thyroid cells and reduces the thyroid’s secretion capacity.

The symptoms of hypothyroidism include:
• Fatigue;
• Unexplained weight gain;
• Cold intolerance;
• Constipation;
• Dry skin, coarse hair and brittle nails;
• Swollen face and legs;
• Difficulty concentrating and poor memory;
• Depression.

As the name suggests, this condition includes the development of nodules or abnormal lumps that can vary in number (can be one or multiple) and size. Most thyroid nodules are benign (non-cancerous), but they can also be malignant.

There are various causes for the development of thyroid nodules, but the most common is iodine deficiency. Furthermore, when the thyroid itself is enlarged, it is more likely to develop nodules.

Nodules are usually only discovered during routine check-ups, as they do not cause symptoms. When they are in an advanced stage, patients may experience swelling in the neck, difficulty swallowing, hoarseness or voice changes, neck pain and, more seldom, difficulty breathing.

Goitre results from the abnormal growth of the thyroid gland, frequently resulting in a visible lump in the neck. This growth can be diffuse, nodular or multinodular. The most common causes of goitre include iodine deficiency, autoimmune disorders and some drugs that affect the thyroid, among others.

This thyroid disease may or may not cause noticeable symptoms. When these occur, symptoms can include:
• Swelling in neck;
• Difficulty swallowing;
• Tightness in throat;
• Hoarse voice;
• Choking sensation;
• Persistent cough.

Hypothyroidism can help cause weight gain, but is not necessarily a direct cause of obesity. When the thyroid gland fails to produce hormones, the body’s metabolism can decrease, which may lead to weight gain or obesity. However, this is not true for everyone with hypothyroidism, and when it does occur, the weight gain is usually insignificant and gradual.

Although iodine is essential for a healthy thyroid, overconsumption can aggravate or provoke thyroid dysfunction. Ordinarily, our daily diet guarantees the necessary iodine intake for good thyroid function.

When untreated, thyroid diseases can increase the risk of complications during pregnancy, such as miscarriage, premature delivery, preeclampsia, low birth weight and intellectual disability in the baby, among others. Therefore, it is important for women who are pregnant (or are planning pregnancy) to closely monitor thyroid health.

Although less frequent, children can also develop thyroid diseases, especially in the event of autoimmune disorders or when, for congenital reasons, the body does not produce a normal amount of hormones.