What Is Thyroid Disease?

  • Maha Ahmed MBBS, Intarnal Medicine and General Surgery, Cairo University, Egypt
  • Ellen Rogers MSc in Advanced Biological Sciences, University of Exeter


At the base of your neck, right below your Adam’s apple, sits a little butterfly-shaped gland called the thyroid. This gland produces thyroid hormone, which is carried throughout your body by your blood and affects several aspects of your body’s metabolism, including how quickly you burn calories and your heartbeat. Thyroid disorders can result in either the overproduction or underproduction of thyroid hormones. As such, individuals with thyroid disease may experience fatigue or agitation or might lose or gain weight, depending on how much (or how little) hormone the thyroid produces. Thyroid disorders are more common in women than males, particularly following menopause and immediately after pregnancy.1

Causes of thyroid disease

Hypothyroidism (underactive thyroid) and hyperthyroidism (overactive thyroid) are the two primary forms of thyroid disease. However, other illnesses that affect the thyroid gland’s functionality and hormone production may be the root cause of other disorders.

 Hypothyroidism can be caused by:

  • Thyroiditis: thyroiditis refers to the inflammation (swelling) of the thyroid gland. Your thyroid’s ability to produce thyroid hormones may be reduced by thyroiditis.
  • Hashimoto’s thyroiditis: Hashimoto’s thyroiditis is an inflammatory disease that causes the thyroid gland to become inflamed. It often causes a goitre (swelling in the neck brought on by an enlarged thyroid gland) and other symptoms. 
  • Postpartum thyroiditis: after giving birth, the thyroid gland may be affected by postpartum thyroiditis, which can result in hyper- or hypothyroidism. Medication can be used to treat it, and in about 80% of instances, it goes away after 12 to 18 months.
  • Iodine deficiency: the thyroid needs the mineral iodine to make thyroid hormones. Several million people worldwide are affected by an iodine shortage.
  • A non-functioning thyroid gland: the thyroid gland occasionally malfunctions from birth. One in 4,000 babies is affected by this. Affected babies may have physical and mental problems in the future if untreated, so all babies receive a screening blood test in the hospital.

Hyperthyroidism can be caused by the following:

  • Graves’ disease: in patients with Graves’ disease, the thyroid may become overactive and release an excessive amount of thyroid hormone. Graves’ disease is also known as “diffuse toxic goitre” (enlarged thyroid gland).
  • Nodules: overactive thyroid nodules can result in hyperthyroidism. A goitre caused by many affected nodules is known as a “toxic multi-nodular thyroid nodule”, whilst a goitre caused by a single nodule becoming overactive is known as a “toxic autonomously functioning thyroid nodule”.
  • Thyroiditis: this condition may not cause any pain but does cause stored (and potentially excessive) hormones to be released. This may continue for several weeks or months.
  • Excessive iodine: if the body contains too much iodine, the thyroid produces more thyroid hormones than it needs. Cough syrup and some drugs, such as the heart medication amiodarone, contain an excessive amount of iodine.2

Signs and symptoms of thyroid disease

Signs and symptoms of hyperthyroidism

  • Nervousness, trembling, and agitation
  • Irritability
  • Inability to focus
  • Reduced menstrual blood flow
  • Palpitation or a pounding heartbeat
  • Heat intolerance
  • Altered bowel activity
  • Thyroid gland enlargement or swelling
  • Skin thinning
  • Brittle hair
  • Increased appetite, hunger, and sweating

Signs and symptoms of Hypothyroidism3

  • Feeling uncomfortable in or being more sensitive to cold water
  • Hoarse throat
  • Dry skin
  • Constipation
  • Fatigue
  • Memory issues
  • Hair loss or thinning
  • Slow heart rate
  • Mental cloudiness or sluggishness
  • Feeling down
  • Excessive or protracted menstrual bleeding
  • Fluid retention, feeling bloated, and facial puffiness
  • Joint aches and pains
  • Weight gain
  • High cholesterol levels 

Management and treatment of thyroid disease

Treating hyperthyroidism

Your age and state of health, as well as the severity and underlying cause of your hyperthyroidism, will determine the best course of action. Further, as you and your healthcare professional choose a course of action, your personal preferences should also be considered. Treatment options include:

  • Anti-thyroid medicine: these drugs gradually reduce the symptoms of hyperthyroidism by inhibiting the production of excess thyroid hormone. Propylthiouracil and methimazole are two anti-thyroid medicines. Anti-thyroid medication treatment normally lasts 12 to 18 months. After that, if symptoms subside and your thyroid hormone levels have returned to normal, the dose may be gradually reduced or stopped altogether.
  • Beta-blockers: While these medications do not directly affect thyroid hormone levels, they can help treat symptoms of hyperthyroidism, such as tremors, fast heartbeat, and palpitations. They may occasionally be prescribed by medical professionals to treat your symptoms until thyroid hormone levels align with normal ranges. People with asthma are often advised against taking these medications. 
  • Radioiodine therapy: like iodine, radioiodine (radioactive iodine) is absorbed by the thyroid and causes it to shrink, reducing the amount of hormone it produces. Radioiodine is administered orally and normally causes your symptoms to fade within a few months. The thyroid gland typically becomes underactive due to this medication, and you may eventually need to take medication to restore your thyroid’s activity to normal levels.
  • Thyroidectomy: This procedure involves removing all, or part of, the thyroid gland. It is not frequently used to treat hyperthyroidism and is mainly reserved for people who cannot take radioiodine therapy or anti-thyroid medications.

Vocal cord and parathyroid gland injury are risks of this procedure.4

Treating hypothyroidism:

  • Levothyroxine: levothyroxine (also known as Levo-T or Synthroid) is a thyroid hormone medication often used to treat hypothyroidism. This medication is taken daily and by mouth. It restores thyroid hormone levels to a healthy range and helps treat symptoms of hypothyroidism. If your doctor decides to give you levothyroxine, they will assess your TSH level about 6 to 8 weeks after you begin taking levothyroxine to determine your optimal dosage going forward. Six months later, you might require another blood test to evaluate your TSH levels. It’s important to note the side effects of levothyroxine, which can include:
    • Tiredness
    • Increased appetite
    • Issues with sleep
    • Shakiness
    • Heart palpitations are often known as heart pounding.

Levothyroxine should be taken at the same time every day on an empty stomach, and you should wait 30 to 60 minutes before eating or taking any other medications. If you take medication before bed, you should wait at least four hours after your last meal to take it.5


The thyroid is a butterfly-shaped gland that is found in the front of the neck and produces hormones that control various aspects of your metabolism. Due to the role of thyroid hormones in our general health and wellbeing, thyroid disorders can affect heart rate, mood, energy level, metabolism, bone health, pregnancy, and many other functions.

Thyroid disorders, which include hypothyroidism, hyperthyroidism, and thyroid nodules, are among the most common illnesses affecting our endocrine (hormonal) system and are commonly identified, diagnosed and monitored by measuring levels of thyroid-stimulating hormone in the blood. Once detected, thyroid diseases can be treated using a range of treatments based on your age, health, and the severity of your disease. Thus, whilst it is important you seek treatment quickly, thyroid diseases are rarely life-threatening, and cases are often treated very effectively.


How is thyroid disease diagnosed?

If your doctor suspects you have a thyroid disease, they will run several tests. These include: 

  • Blood tests: Blood tests can help diagnose abnormalities or disorders associated with hypertension or hypothyroidism. These include:
    • Thyroiditis
    • Graves’ disease
    • Hashimoto’s disease
    • Goiter
    • Thyroid nodule
    • Thyroid cancer

Specifically, your doctor will check the levels of the following thyroid hormones and chemicals in your blood: 

  • Thyroid-stimulating hormone (TSH)
  • Thyroxine (T4)
  • Free Thyroxine (FT4)
  • Triiodothyronine (T3)
  • Free Triiodothyronine (FT3)
  • Thyroid antibodies
  • Calcitonin
  • Thyroglobulin 
  • Imaging tests: in many instances, visually examining the thyroid can provide your doctor with a wealth of information. As such, your doctor may perform a thyroid scan. This allows them to look at your thyroid and check for abnormalities in its size or shape or the presence of growths (nodules) on it. Your doctor may also use an ultrasound.
  • Physical exam: a physical exam performed in your doctor’s office is another easy technique to examine the thyroid. During this quick and painless test, your doctor will feel your neck for any growths or swelling.

Can thyroid disease be prevented?

The following precautions may help lower your risk of thyroid disease:

  • Quit smoking
  • Consume less soy
  • Request to wear a thyroid collar during X-rays to shield your thyroid gland from radiation exposure
  • Consume selenium supplements
  • Regular health checkups 

Who is at risk of thyroid disease?

You may have an increased risk of thyroid disease if:

  • You have a relative with thyroid disease.
  • You have Sjogren syndrome, Turner syndrome, Type 1 diabetes, primary adrenal insufficiency, lupus, or rheumatoid arthritis.
  • You use iodine-rich medications, such as amiodarone.
  • You are above 60 (particularly women).
  • You have previously received therapy for a thyroid disorder or cancer (such as thyroidectomy or radiation)

How common is thyroid disease?

According to the American Thyroid Association, more than 12% of people will develop a thyroid issue at some point in their lives. Further, women are five to eight times more likely than men to experience thyroid issues, particularly after childbirth and menopause. Despite this, thyroid disease frequently goes undiagnosed - with up to 60% of people unaware they have it. This statistic highlights the importance of getting regular medical checkups.

When should I see a doctor?

You should get your thyroid tested if you have noticed any of the following symptoms:

  • Dramatic weight loss/gain without significantly altering your lifestyle 
  • Changes in your appearance, such as weaker or more brittle hair, dry, red, itchy, thinning, or irritated skin, swelling in your joints, a swollen face, or swelling at the base of your neck
  • Insomnia, fatigue, muscle weakness, and/or sensitivity to heat and cold.
  • Missing periods without being pregnant


  1. Women’s Health. Thyroid disease [Internet]. [Cited 2023 Feb 27]. Available from: https://www.womenshealth.gov/a-z-topics/thyroid-disease
  2. Cleveland Clinic. Thyroid disease: causes, symptoms, risk factors, testing & treatment [Internet]. [Cited 2023 Feb 27]. Available from: https://my.clevelandclinic.org/health/diseases/8541-thyroid-disease
  3. MedicineNet. 30 thyroid disease symptoms, signs, types, and treatments [Internet]. [Cited 2023 Feb 27]. Available from: https://www.medicinenet.com/thyroid_disease_symptoms_and_signs/article.htm
  4. McDermott MT. Hyperthyroidism. Ann Intern Med. 2020;172:ITC49. 
  5. Mayo Clinic. Hypothyroidism (Underactive thyroid) [Internet]. [Cited 2023 Feb 27]. Available from: https://www.mayoclinic.org/diseases-conditions/hypothyroidism/diagnosis-treatment/drc-20350289
This content is purely informational and isn’t medical guidance. It shouldn’t replace professional medical counsel. Always consult your physician regarding treatment risks and benefits. See our editorial standards for more details.

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Jaya Choudhary

Bachelor of Dental Surgery, MBA-HA, India

Jaya is a Dental surgeon with MBA in Hospital Administration. She has 2 years of
experience with exposure to both clinical and non-clinical work environments and a strong
passion for medical writing and educating the public about health and wellbeing.

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