Hyperthyroidism

Based on the underlying cause, the main types of hyperthyroidism are the following:

• Graves’ disease or toxic diffuse goiter
• Toxic multinodular goiter (Plummer’s disease), in which multiple thyroid nodules produce excessive hormones
• Toxic solitary adenoma, where a single nodule is hyperfunctioning
• Subacute thyroiditis, a transient inflammation of the thyroid gland causing temporary hyperthyroidism
• Iatrogenic (drug-induced) hyperthyroidism, caused by excessive intake of thyroxine or other medications

The symptoms of hyperthyroidism vary, involve nearly all body systems, and may appear suddenly or gradually. Some of the most common include:

• Fatigue, muscle weakness, and easy exhaustion
• Tachycardia, palpitations, or a “fluttering” sensation
• Irritability, nervousness, and anxiety
• Hand tremors
• Increased sweating and heat intolerance
• Sleep disturbances (insomnia)
• Weight changes
• Menstrual irregularities
• Watery stools or diarrhea
• Thyroid enlargement (goiter)
• Eye disorders such as exophthalmos, dryness, blurred vision, or diplopia
• Thin and fragile skin and hair
• Osteopenia, osteoporosis
• Reduced sexual drive
• Low mood or depression
• Severe anxiety and mood fluctuations

Mild subclinical hyperthyroidism is characterized by low TSH levels, while thyroid hormones FT4 and FT3 remain within normal limits, and it usually does not present with obvious symptoms.

Suspicion for hyperthyroidism arises when some of the above symptoms are present. However, in some cases there are no symptoms, leading to what is known as latent or subclinical hyperthyroidism.

Diagnosis is confirmed through blood tests measuring thyroid hormone levels. A hallmark finding is suppressed thyroid-stimulating hormone (TSH) accompanied by elevated T3 and T4 levels (and their free fractions FT3 and FT4). Thyroid autoantibodies are also measured.

Thyroid-stimulating hormone (TSH) is produced and secreted by the pituitary gland and stimulates the thyroid gland to produce thyroxine (T4) and subsequently triiodothyronine (T3), which affects the metabolism of nearly all body tissues.

Low TSH indicates HYPERTHYROIDISM, while high TSH indicates HYPOTHYROIDISM.

Normal TSH levels generally range from 0.40 to 4.00 mIU/L and depend on age, sex, pregnancy, and other factors.

TSH plays a critical role through the negative feedback mechanism, regulating metabolism, growth, and energy expenditure. It influences metabolic rate, cardiac function, digestion, muscle control, and brain development.

Hyperthyroidism accelerates metabolism, leading to increased energy consumption and unintentional weight loss, despite increased appetite.

Because appetite is also increased, some patients may not lose weight or may even gain weight, depending on caloric intake.

Dietary and other factors that should be avoided in hyperthyroidism include:

• Fish, seafood, and shellfish
• Seaweed products and soy products
• Gluten (protein in wheat, barley, rye), nitrates
• Antiseptics and food preservatives
• Exposure to mercury (heavy metals)
• Infections from the herpes virus family (HSV) and Epstein–Barr virus (EBV)
• Certain medications (e.g., the antiarrhythmic drug amiodarone)

Hyperthyroidism is closely linked to a patient’s psychological state, as it often causes intense symptoms that significantly affect daily life. These include anxiety, irritability, nervousness, emotional instability, and persistent unexplained stress.

Historically, individuals with Graves’ disease were sometimes mistakenly confined to psychiatric institutions, as medical science at the time was unaware of this thyroid disorder and its now readily available treatment.

The autoimmune nature of hyperthyroidism, through hormonal dysfunction, can impair conception and the successful completion of pregnancy. Surgical treatment often provides a definitive solution for couples wishing to conceive, with many achieving pregnancy postoperatively.

Uncontrolled hyperthyroidism during pregnancy carries serious risks, including miscarriage, preterm delivery, preeclampsia, low birth weight, and cardiac complications for both mother and fetus. Additionally, antithyroid drugs cross the placenta and may cause fetal goiter, hypothyroidism, or neurological complications in the newborn.

Untreated or poorly controlled hyperthyroidism may lead to:

• Cardiovascular complications, including atrial fibrillation, which may cause stroke or heart failure
• Arterial hypertension
• Osteoporosis and fractures
• Glucose intolerance, insulin resistance, and hyperinsulinemia
• Menstrual disturbances such as oligomenorrhea or amenorrhea
• Reduced libido, infertility, erectile dysfunction in men, oligospermia, and sterility
• Severe ophthalmopathy: exophthalmos, dry eyes, discomfort, photophobia, blurred vision, diplopia, reduced eye mobility
• Thyroid storm (thyrotoxic crisis), a life-threatening condition characterized by high fever, severe tachycardia, confusion, and reduced consciousness

Temporary disease remission may be achieved with antithyroid medications. 

These potent drugs (methimazole, carbimazole, propylthiouracil) reduce thyroid hormone production and are typically administered for 6 to 18 months. Long-term use is discouraged due to risks such as hepatotoxicity (liver damage) and hematological side effects (leukopenia). Adverse effects may include rash, hair loss, dizziness, aplastic anemia, lupus-like syndrome, and hepatitis.

Frequent blood tests are required for dose adjustments. They achieve a temporary remission of the disease, however, as an autoimmune disorder, it may relapse at any time.

Beta-blockers are often prescribed to alleviate symptoms such as arrhythmias, anxiety, muscle weakness, and nervousness. They provide purely symptomatic relief while it is being administered, without curing the underlying disease.

Radioactive iodine is another conservative treatment approach. It involves the administration of radioactivity to the patient with the aim of gradually destroying the hyperfunctioning thyroid cells. This often results in hypothyroidism and the need for lifelong thyroxine replacement therapy. The radioactive energy “ablates” the thyroid tissue, however, because the thyroid gland remains in the body, compressive symptoms may still occur, and the risk of malignant transformation, although low, remains present. Radioactive iodine therapy is also frequently associated with worsening of thyroid eye disease. Finally, the use of radioactive iodine imposes restrictions in cases where pregnancy is desired.

In Europe, radioactive iodine therapy is not widely practiced.

Today, hyperthyroidism due to Graves’ disease can be treated safely, definitively, and effectively with thyroidectomy.

It is noteworthy that the hyperthyroid state, through the psychological disturbances it induces, often prevents the individual from making the decision to pursue a definitive solution to the problem. Unfortunately, the patient may enter a vicious cycle that makes it difficult to reach a rational decision regarding definitive treatment.

Surgical removal of the thyroid gland (thyroidectomy) offers significant advantages over other treatments, including:

• Provides a safe and definitive cure of the disease, maintaining long-term therapeutic effectiveness
• Offers a reduced cardiovascular risk compared with medical therapy
• Reduces the incidence of atrial fibrillation compared with pharmacological treatment
• Decreases the risk of developing diabetes mellitus
• Has a comparatively minimal recurrence rate when performed by a specialized endocrine surgeon
• Eliminates exposure to the adverse effects of potent antithyroid medications, which are contraindicated for lifelong use
• Relieves the patient from the burden and cost of frequent hormonal testing and repeated endocrinological evaluations
• Contributes to avoiding the administration of high doses of radioactivity (I-131 therapy), benefiting both the patient and their close environment
• Provides a definitive solution by removing an enlarged thyroid gland that causes compressive symptoms
• Ensures complete excision of the pathological tissue (which is always subjected to histological examination), thereby allowing simultaneous removal of coexisting thyroid carcinomas
• Definitively corrects hormonal dysfunction, freeing the body from the systemic adverse effects of hyperthyroidism across multiple organs and systems
• Finally, it leads to a remarkable improvement in the psychological disturbances associated with the disease

Graves’ disease is a treatable condition that can be fully controlled surgically. 

In most cases, the improvement in quality of life is dramatic.

Postoperatively, patients experience relief from constant tension and anxiety and regain stable physical and psychological well-being.

Dr. Evangelos Karvounis MD, PhD, FACS is an award-winning endocrine surgeon, PhD graduate of the Medical School of Athens, Fellow of the American College of Surgeons, and Director of Endocrine Surgery at Euroclinic of Athens. He is available to answer all questions regarding hyperthyroidism and to recommend individualized treatment. Contact the doctor today by phone or through the contact form to schedule your appointment for accurate diagnosis and personalized care.