What are thyroid diseases?
The thyroid is a gland in the lower front of the neck. Through the hormones it secretes, it affects many of the body’s functions. Thyroid diseases may present as the gland working too little or too much, becoming enlarged (goitre), or developing nodules. The diagnosis rests on blood tests and examination together.
The General Directorate of Public Health (opens in a new tab) of the Ministry of Health of the Republic of Türkiye states that iodine is necessary for the gland to produce thyroid hormones, and describes goitre as the best-known consequence of iodine deficiency. The same source reports that iodine deficiency is one of the leading causes of preventable intellectual disability, and that women of childbearing age, pregnant women, infants and children make up the highest risk group.
Table salt contains iodine under the programme for the prevention of iodine deficiency disorders and the iodisation of salt, which has been running in Türkiye since 1994.
What are the symptoms?
Symptoms do not establish a diagnosis on their own; they are assessed together.
Symptoms that may be related to enlargement of the gland
- Swelling or fullness in the neck
- A feeling of something catching when swallowing
- Hoarseness
- Shirt collars beginning to feel tight
Symptoms that may be seen when the hormone level is lower than expected
- Fatigue
- Feeling cold
- Dry skin
- Hair loss
- Constipation
- Weight gain
- Forgetfulness
- Menstrual irregularity
Symptoms that may be seen when the hormone level is higher than expected
- Palpitations
- Trembling of the hands
- Excessive sweating
- Intolerance of heat
- Weight loss
- Insomnia
- Restlessness
- Diarrhoea
Because some of the symptoms progress slowly, they may be noticed late.
How is the diagnosis made?
- Medical history. When the symptoms began and how they are progressing, family history, previous thyroid investigations, any history of radiotherapy to the neck, and all current medication and supplements.
- Examination of the neck. The physician assesses by hand the size and consistency of the gland and whether any lump can be felt within it.
- Blood tests. Thyroid function tests are requested; where necessary, antibody levels are added.
- Imaging. According to the examination and the test results, a thyroid ultrasound may be requested.
- Further assessment. If a nodule is detected, additional investigations or referral to the relevant specialty may be needed, depending on its characteristics.
In which patients is it assessed differently?
- In pregnant patients and in patients planning a pregnancy, the reference ranges for thyroid hormones are different, and follow-up takes place at closer intervals and jointly with obstetrics and gynaecology
- In patients who are breastfeeding
- In patients with a history of radiotherapy to the neck
- In patients with a family history of thyroid cancer
- In patients with a heart rhythm disorder, because thyroid hormones may affect the rhythm, the assessment is made jointly
- In patients with osteoporosis, the targets for hormone levels may be set differently
- In patients over 65, the symptoms may be subtle
- In patients under 18 years of age, follow-up lies within the field of paediatric endocrinology
Follow-up and how often it takes place
Because every patient’s course unfolds differently, it would be wrong to give a definite answer on how often follow-up is needed; the interval is determined according to the clinical picture and the medicine being taken. In patients who have been started on a medicine or whose dose has been changed, blood tests are repeated after a certain period and the dose is adjusted where necessary. Where the course is stable, the interval may lengthen.
In patients in whom a nodule has been detected, follow-up is planned according to the characteristics of the nodule, and imaging may be repeated at set intervals.
What should you do before and after the consultation?
When you come for the consultation, bring:
- A list of all the medicines and supplements you use
- Your previous thyroid test results
- Your ultrasound report, if you have one
Report products containing iodine or biotin in particular; they may affect some tests.
If treatment has been started: the physician sets the time of day at which the medicine is taken and the gap between it and other medicines. Keeping to this routine matters if the results are to be assessed correctly.
Risks and points to be aware of
A single test result is not assessed on its own. Laboratory reference ranges may differ from one institution to another, and they change in pregnancy.
Do not take products containing iodine on your own initiative. Taking iodine unnecessarily or in a high dose may affect thyroid function. Table salt already contains iodine under the programme; additional iodine requires assessment by a physician.
Do not change the dose of your medicine on your own initiative. With hormone medicines, a change of dose may have consequences for heart rhythm and bone health.
Not every swelling that can be felt in the neck means the same thing. The distinction is made by examination and, where necessary, imaging.
Some supplements may affect test results. Report every product you take.
Results vary from person to person.
When should you see a physician without delay?
If you notice these symptoms, consult a physician without delay:
- Swelling in the neck that is enlarging rapidly
- Hoarseness that does not go away
- Difficulty swallowing or a feeling of something catching in the throat
- Difficulty breathing that increases over days
- Marked palpitations, trembling of the hands, excessive sweating
- Unintentional and rapid weight loss
- A hard, painless mass felt in the neck
In the event of sudden shortness of breath or an inability to swallow, go directly to the emergency department.
Frequently asked questions
Which tests are requested for the thyroid?
Thyroid function tests are generally the starting point; according to the examination and the results, antibody levels may be added. Where necessary, a thyroid ultrasound is requested. Which of these are needed depends on your complaint.
Are goitre and thyroid disease the same thing?
Goitre describes enlargement of the thyroid gland. The gland may be enlarged while the hormone levels are within the healthy range, or the hormone level may have changed while the gland is not enlarged. For this reason, the size of the gland and the hormone level are assessed separately.
Do I have to take thyroid medicine permanently?
This depends on what is causing the clinical picture. In some situations the treatment is temporary; in others long-term monitoring is needed. The duration cannot be determined in advance; it is reassessed at follow-up.
I have a nodule; should I be worried?
Thyroid nodules are common, and most are of a type that calls for monitoring. The characteristics of the nodule are assessed with ultrasound and, where necessary, additional investigations. The follow-up plan is drawn up according to this assessment.
Does thyroid disease get better with diet?
Nutrition plays a part in thyroid health through iodine intake. However, the management of a diagnosed thyroid disease is planned by a physician, and changes to diet do not replace treatment.
Is follow-up different in pregnancy?
Yes. In pregnancy the reference ranges for thyroid hormones change and follow-up takes place at closer intervals. If you are pregnant or planning a pregnancy, please say so at the beginning of the consultation.
Sources
- Ministry of Health of the Republic of Türkiye, General Directorate of Public Health, Küresel İyot Eksikliği Bozukluklarını Önleme Günü (iodine, thyroid hormones and the salt iodisation programme). https://hsgm.saglik.gov.tr/tr/haberler-cocukergen/kuresel-iyot-eksikligi-bozukluklarini-onleme-gunu.html (opens in a new tab)
- World Health Organization, Noncommunicable diseases fact sheet, 25 September 2025. https://www.who.int/news-room/fact-sheets/detail/noncommunicable-diseases (opens in a new tab)
