FAQs of Thyroid disease

The thyroid or thyroid gland is a butterfly-shaped endocrine gland normally located in the lower part of the front of the neck, above the sternum, in front of the trachea and the oesophagus. Under normal conditions it weighs between 15-20 grams, but it can reach hundreds of grams if there is a goitre.  

The thyroid gland produces thyroid hormones that are secreted into the blood and reach all the tissues in the body. The main thyroid hormones are thyroxine (L-thyroxine or T4) and triiodothyronine (T3). The main thyroid hormone in the blood is T4, while T3 is formed only in some tissues (brain, liver) by converting T4. Producing a normal amount of thyroid hormones requires an adequate intake of iodine, at least 100-150 micrograms a day.  

Thyroid hormones help the body to use energy and keep the so-called ‘basal metabolism’ stable, thus maintaining the body temperature required for the brain, heart, muscles and other organs to function under the optimal conditions necessary for the body’s processes.  

Control of thyroid gland function is primarily performed by the pituitary gland (also known as the hypophysis), a gland located at the base of the skull behind the bridge of the nose (see introduction to pituitary tumours chapter, figure 3) via a positive stimulation-type control mechanism in the case of a lack of hormones, and negative feedback (inhibition) in the case of an excess of peripheral thyroid hormones. At the same level as the hypothalamus, above the pituitary gland, TRH (thyrotropin-releasing hormone) is synthesised. This acts at the level of the pituitary gland and induces the production of TSH (thyroid-stimulating hormone). This TSH stimulates the follicular cells to produce thyroid hormones. If there is an excess of circulating thyroid hormones, these act on the hypothalamus and pituitary to decrease the production of TRH and TSH, respectively, to balance the hypothalamic-pituitary-adrenal axis and normalise thyroid hormone production. If, on the other hand, there is a lack of circulating thyroid hormones, TRH and TSH are stimulated to increase, so that thyroid hormone synthesis is induced.  

Hypothyroidism may be associated with a slight increase in weight, which is more or less significant depending on the patient and the degree of hypothyroidism. In the case of isolated weight gain without other accompanying symptoms such as tiredness, fatigue, sluggishness, feeling cold, low mood, impaired memory, constipation, drowsiness, slight weight gain, pallor, dry skin, hair loss and loss of the distal part of the eyebrows, aching muscles, irregular menstruation or increased bleeding, it is unlikely that the weight gain is due to hypothyroidism. If considerable weight gain is not explained by changes in diet or physical activity, consult your primary care physician. 

If your thyroid function is normal, with normal thyrotropin (TSH) and free thyroxine (free T4) values, there should be no substantial changes in weight and your tendency to gain or lose weight will be more closely related to changes in your diet and physical activity than to your hypothyroidism.  

Weight loss is one of the ways in which hyperthyroidism presents. It will be more pronounced the greater the degree and duration of hyperthyroidism. 

The symptoms of hyperthyroidism can, at first, be confused with an exaggerated stress response. This is why the diagnosis is sometimes made later, when the clinical presentation has progressed further. As the disease progresses, the clinical picture becomes clearer and the symptoms become more severe, for example increased sensitivity to heat, irritability, increased sweating, palpitations, hand tremors, anxiety, increased bowel transit (without diarrhoea), difficulty sleeping, warmer and thinner skin, thin and fragile hair, muscle weakness in the arms and thighs, altered menstrual rhythm and mild-to-moderate weight loss with sustained appetite.  If you have significant weight loss that cannot be explained by changes in diet or physical activity and/or any of the above symptoms, consult your primary care physician.  

Thyroiditis means inflammation of the thyroid gland.  As with inflammation of any organ in the body, thyroiditis can have several causes. Additionally, depending on the causes of thyroiditis, the duration may be longer or shorter, resulting in acute, subacute or chronic thyroiditis.  Thyroiditis treatment generally combats symptoms depending on their severity: pain, thyrotoxicosis or hypothyroidism. Antibiotic treatment may also be necessary if there is infection. The pain associated with subacute thyroiditis can be controlled with anti-inflammatory drugs, such as aspirin or ibuprofen (accompanied by gastric protection). Severe pain requires treatment with corticosteroids (e.g. prednisone). If the thyrotoxicosis produces symptoms of hyperthyroidism, non-selective beta-blocker drugs such as propranolol are recommended. Antithyroid drugs are not used routinely because the symptoms of thyrotoxicosis are secondary to hormones being released into the blood from the inflamed thyroid and not a result of increased hormone production from the thyroid gland itself.  In cases of Hashimoto’s thyroiditis, chronic hormone replacement therapy with Levothyroxine is prescribed. In the hypothyroid stage of subacute thyroiditis and postpartum hypothyroidism, hormone replacement therapy with thyroxine is given for approximately 6-12 months in patients with symptoms or significant analytical alterations. After this, the dose is gradually reduced to assess whether or not thyroid hormone is needed on a permanent basis. In most patients, thyroid function recovers (see thyroiditis treatment). 

Graves-Basedow Disease (GBD) is the most common form of autoimmune hyperthyroidism that activates the thyroid via antibodies that stimulate the thyroid hormone-producing cells that cause hyperthyroidism. In addition to hyperthyroidism and diffuse enlargement of the thyroid gland, this disease typically affects the eyes and, in some cases, also the skin (see Graves-Basedow disease). 

Hyperthyroidism treatment depends on the cause of the disease, the severity of the symptoms and your age.  Generally, it is treated with drugs that lower the level of thyroid hormones in the blood (synthetic antithyroid drugs) and those that also lower the side effects of these hormones (beta-blockers and anxiolytics). Depending on the cause of the hyperthyroidism, and after 12-18 months of treatment, definitive treatment is necessary to eliminate the cause of the hyperthyroidism: surgical removal of the gland or its partial destruction using radioactive iodine (see hyperthyroidism treatment). 

Worldwide, the most common cause of goitre formation is sustained dietary iodine deficiency, known as endemic goitre. Thyroid hormones have a high iodine content. The thyroid gland cannot produce enough thyroid hormone if it does not have enough iodine. As a result, it will produce an insufficient quantity of hormones, which will then lead to hypothyroidism. As a result, the pituitary gland detects low levels of thyroid hormones, and sends a signal hormone to the thyroid gland to stimulate the thyroid. The signal hormone is called thyrotropin (thyroid-stimulating hormone, or TSH). TSH stimulates the thyroid to produce the necessary amount of thyroid hormone at the expense of an increase in size, leading to the formation of a ‘goitre’ in accordance with the duration and intensity of the iodine deficiency.    

Iodine is found naturally in sea products as well as in plants that grow in iodine-rich soils. Salt for daily use is often fortified with iodine, and is known as iodised salt. In developed countries like Spain, the countries in the European Union and the United States, iodine deficiency is no longer a common problem thanks to epidemiological, socio-health and population education measures that promote the consumption of iodised salt. However, there are still areas and communities where iodine deficiency remains a problem.

Thyroid nodules are the most common endocrinological problem in our field. More than 95% of thyroid nodules are benign. Nodules may be silent and cause no symptoms, or they may grow and cause discomfort due to their size, or because they function independently from the rest of the thyroid (toxic nodule). However, up to 5% of thyroid nodules may be malignant. This means that when assessing a thyroid nodule, the main goal is to rule out its malignant potential. Approximately 1 in 10 people have a thyroid nodule and approximately 9 out of 10 nodules are benign (they do not contain cancer).

The vast majority of nodules tend to be asymptomatic and benign. Depending on the symptoms, the number and size of the nodules, their anatomical position, the ultrasound findings, and the result of the nodule puncture (as well as whether or not the nodule has altered thyroid function) follow-up with ultrasound and blood tests, size-reducing treatment or surgical excision is usually indicated.    

If the cytology shows malignancy or suspicion of malignancy, the indication is to have the entire thyroid gland removed (total thyroidectomy) by a specialist surgeon. A very high percentage of thyroid cancers are curable.    

If the cytology is benign, the size is small and the patient is asymptomatic, follow-up is usually performed with a physical examination and ultrasound to assess the growth of the nodule, initially at 6 months and then more or less frequently, depending on the size of the nodule. If the nodule shows a significant increase in size, it may be necessary to repeat the FNA (fine needle aspiration) to re-evaluate it. Surgery is recommended if the nodule causes symptoms of cervical compression due to its enlarged size.     If the nodule is cystic and it is large or uncomfortable, ultrasound-guided drainage of the fluid content may be performed. If this is not sufficient, it can be treated percutaneously by introducing sterile alcohol into the cyst to sclerose (harden) the cyst walls, thereby preventing recurrence. This may or may not be followed by percutaneous thermal treatment.    

(See thyroid nodule treatment)

Thyroid surgery is performed at specialist centres by expert surgeons. The conventional approach is at the level of the anterior neck, but there are innovative approaches that aim to prevent visibility of the scar by accessing the thyroid through the axilla (underarm) or the oral cavity, without increasing postoperative complications.

The risk of complications from this surgery is usually low, and depends on the experience of the surgical team, as well as the size of the thyroid and the individual’s anatomy. Specific complications include bleeding and cervical haematoma, decreased calcaemia due to involvement of the parathyroid glands and hoarse or dysphonic voice resulting from damage to the nerves controlling the vocal cords. In cases of partial thyroidectomy, hemithyroidectomy +/- isthmectomy or percutaneous treatments, local complications are even less frequent, but the thyroid function should be monitored and ultrasound monitoring performed to check whether any nodules are left in the remaining thyroid. In cases of total thyroidectomy for multinodular goitre, lifelong treatment with thyroxine is required. 

In radioactive iodine treatment, iodine is administered orally (capsule) or intravenously and enters the thyroid, where it is taken up by the overactive cells, and then slowly damages the thyroid cells over the next weeks or months.  Any free iodine remaining in the blood is excreted in 2-3 days, in urine, in a non-radioactive form.    

Radioactive iodine treatment for hyperthyroidism is carried out at the hospital’s nuclear medicine unit on an outpatient basis. Antithyroid treatment should be interrupted a few days beforehand to improve radioiodine uptake, but beta-blockers or anxiolytics should not be interrupted. The nuclear medicine team will give you all the necessary instructions before treatment. After treatment, antithyroid treatment will be re-initiated for one month. A blood test will be performed to assess the response of the patient’s thyroid to the treatment.  

The result of the treatment with iodine consists of reduction of the size of the thyroid and the progressive decrease of the levels of thyroid hormone in a few months. Most patients treated for hyperthyroidism will have an underactive thyroid (hypothyroidism) and will eventually require replacement therapy with Levothyroxine in a single daily dose. In some patients, the thyroid hormone level cannot be lowered enough to cure hyperthyroidism, in which case a second treatment with radioactive iodine will be required. This is a very safe treatment, and it is associated with very few complications.

If the patient chooses not to undergo surgery voluntarily or cannot undergo surgery due to a high surgical risk, percutaneous thermal ablation/reduction of the thyroid nodule is recommended. These percutaneous treatments are performed at specialist centres using ultrasound guidance, with or without sedating the patient, using targeted laser probes, radiofrequency, microwaves or ultrasound to necrotise the nodule with heat, while maintaining the rest of the thyroid and its function.

If your primary care physician or endocrinologist tells you that your hypothyroidism requires treatment with Levothyroxine, in most cases this will be a lifelong treatment. There are some exceptions, such as viral thyroiditis, in which thyroid function can recover after a few months. It may be necessary to adjust the dose of thyroxine over time. If you follow the prescribed daily treatment, you will remain free of the secondary symptoms of hypothyroidism and your quality of life and longevity will not be affected.

In general, people with thyroid disease usually have a good quality of life, with no particular limitations in terms of diet, exercise, work or sexual activity. Moderate dietary iodine intake (iodised salt, fish and vegetables) is recommended, with some exceptions: if in doubt, consult your doctor. If you present hypothyroidism, thyroid hormone replacement therapy with Levothyroxine may be required. This treatment is oral, easily administered, and taken daily.  If you have hyperthyroidism, you may require medical treatment. At first this will be temporary, until your thyroid function is controlled or your doctor suggests definitive treatment, which would mean radioactive iodine treatment and thyroidectomy.  If you have large thyroid nodules or goitre, you may experience difficulty swallowing, voice changes, or even occasional shortness of breath. In these cases, surgical treatment is usually indicated to improve the symptoms and your quality of life.    

The recommendations on toxic habits are similar to the general population: quitting smoking and low alcohol consumption are advised. A healthy diet is also recommended. If you undergo thyroid surgery, physical activity will be limited in the immediate postoperative period and can be gradually reintroduced depending on the surgeon’s instructions and the type of work or physical activity involved. Patients can travel normally. In cases where replacement treatment for hypothyroidism or medical treatment of hyperthyroidism is required, it is recommended that you pack enough medication for the whole trip. If possible, you should pack at least a few days’ doses in your hand luggage to prevent issues in the event that your checked-in luggage is lost.

Pregnancy is not contraindicated in principle. However, it is important to discuss this with your endocrinologist so you can plan your pregnancy and adjust your medication. In the case of replacement therapy for hypothyroidism, it is important that you inform your doctor of your pregnancy so that your dose can be increased. You will also be given guidelines to follow, and check-ups will be performed during pregnancy. In the case of hyperthyroidism, it is preferable to postpone pregnancy until the situation has been resolved. It is therefore important to inform your doctor of your desire to have a baby so that the best treatment can be planned. Iodine ablation treatment contraindicates pregnancy for about 6-12 months after the procedure and until thyroid function has been stabilised due to the risk of foetal malformation.

Thyroid pathology is a field of medical and surgical scientific interest, and there are multiple lines of research.    

Firstly, there are lines of surgical research that assess the results of thyroid surgeries using different approaches, and that assess complications and repercussions on quality of life, as well as the application of techniques using cutting-edge technology.

Hospital Clínic is a pioneer in the transaxillary approach and the application of sentinel node detection to localise nodal disease in patients with thyroid cancer.  

In the medical scope, Hospital Clínic has several ongoing lines of research, including work on the molecular basis of sporadic and hereditary thyroid cancer in order to assess prevention, early diagnosis, prognosis and drug response. Hospital Clínic also participates in multiple clinical trials for the systemic treatment of advanced thyroid cancer. New hybrid imaging techniques are also being investigated for diagnostic certainty relating to benign/malignant thyroid nodules. Likewise, minimally invasive percutaneous thermal ablation techniques are being investigated for the echo-guided ablative treatment of symptomatic benign thyroid nodules.  

The following research studies are currently being conducted at our centre. They focus on the differential diagnosis and medical and surgical treatment of nodular thyroid pathology:

• Assessment of short- and long-term complications and quality of life of the transaxillary approach in thyroid surgery. 

• Application of sentinel node detection for the localisation of nodal disease in patients with thyroid cancer. 

• Application of a hybrid diffuse ultrasound-optical tool in the differential diagnosis of thyroid nodules with non-diagnostic cytology. 

• Assessment of complication treatment and the long-term recurrence of benign thyroid nodules after percutaneous thermal ablative treatment (microwave, laser, radiofrequency). 

• Study of the molecular basis of sporadic and hereditary thyroid cancer to assess prevention, early diagnosis, prognosis and drug response.