When the thyroid is underactive (hypothyroidism) or overactive (hyperthyroidism), it disrupts hormone balance and affects multiple body systems. Hypothyroidism causes fatigue, weight gain, and cold intolerance, while hyperthyroidism leads to weight loss, palpitations, and heat sensitivity.
Hypothyroidism occurs when thyroid hormone production is insufficient. This condition slows metabolism, impairs concentration, and may cause dry skin, constipation, and mood changes, requiring timely diagnosis and hormone replacement therapy.
Hyperthyroidism results from excessive thyroid hormone secretion. It accelerates heart rate, induces tremors, anxiety, and muscle weakness, often linked to conditions such as Graves’ disease or toxic multinodular goiter.
Diagnostic evaluation includes blood tests for TSH, T3, and T4 levels, supported by ultrasound or scintigraphy. Early detection enables appropriate treatment, ranging from medication and radioiodine therapy to interventional or surgical approaches.
What Health Problems Occur When the Thyroid Gland Is Underactive?
When the thyroid gland is underactive, a condition called hypothyroidism develops, causing a series of health problems. The common symptoms of hypothyroidism negatively affect the body’s general functioning. Metabolism slows down, leading to weight gain and low energy. Patients also often report increased cold sensitivity. Dry skin and hair are other symptoms caused by this condition.
Fatigue:
Persistent tiredness and lack of energy.
Weight Gain:
Weight increase due to a slower metabolism.
Mental Health Issues:
Depression and cognitive impairment.
Physical Sensitivities:
Increased sensitivity to cold, dry skin and hair.
Digestive Problems:
Digestive issues such as constipation.
These health issues can lead to more serious complications over time. Enlargement of the thyroid gland, known as goiter, can cause difficulty swallowing or breathing. The risk of heart disease increases, especially due to high cholesterol levels. Peripheral neuropathy causes pain and numbness due to nerve damage.
How Does Excess Production of Thyroid Hormones Affect the Body?
Excessive production of thyroid hormones, known as hyperthyroidism, affects various systems in the body. This condition leads to a significant increase in metabolic rate.
- Cardiovascular effects: rapid heart rate and excessive cardiac workload increase the risk of heart failure.
- Metabolic changes: weight loss and increased sweating despite high appetite.
- Neurological effects: irritability, anxiety, tremors, and sleep problems.
- Musculoskeletal effects: muscle weakness and persistent fatigue.
- Gastrointestinal effects: increased bowel movements, possibly diarrhea.
- Eye health: notable swelling of the eyes and double vision may develop.
- Skin: skin swelling and color changes, especially related to Graves’ disease.
- Skeletal system: decreased bone density, leading to osteoporosis and fractures.
- Reproductive system: menstrual irregularities and fertility issues.
What Complications May Develop If Hypothyroidism Is Untreated?
If hypothyroidism is left untreated, many serious health problems can arise. These complications affect various systems in the body and significantly lower the patient’s quality of life. The risk of heart disease increases because high LDL cholesterol levels can cause the arteries to harden. This sets the stage for heart failure and stroke. In addition, thyroid gland enlargement can lead to goiter, causing difficulty swallowing and breathing.
Cardiovascular Problems:
Arterial hardening, heart attack, and stroke risk.
Goiter:
Difficulty swallowing and breathing.
Mental Health Issues:
Depression and slowed mental function.
Myxedema Coma:
A critical condition involving hypothermia and confusion.
Peripheral Neuropathy:
Pain and numbness in the extremities.
Infertility and Menstrual Problems:
Irregular menstrual cycles and infertility.
Muscle and Joint Problems:
Muscle weakness and carpal tunnel syndrome.
Anemia:
Fatigue and weakness.
Pregnancy Complications:
Preeclampsia and premature birth.
Metabolic Issues:
Weight changes and sensitivity to cold.
Skin and Hair Issues:
Dry skin and hair loss.
Other Hormonal Issues:
Kidney dysfunctions.
The psychological effects should also not be ignored; depression and slowed mental functions are common. Severe cases can lead to life-threatening conditions such as myxedema coma, which requires urgent intervention. Hypothyroidism also negatively impacts the nervous system, leading to peripheral neuropathy.
What Are the Symptoms of Hyperthyroidism and How Is It Diagnosed?
The symptoms of hyperthyroidism occur when the thyroid gland is overactive. This condition speeds up energy metabolism, causing various physical and psychological effects. Individuals usually experience increased appetite despite losing weight. There is also an increase in body temperature and sweating, resulting in excessive heat sensitivity. Heart rate acceleration or irregularities may occur, felt as palpitations. The nervous system effects include irritability, anxiety, and tremors.
Muscle weakness is particularly noticeable in the upper arms and legs. Thinning of the skin and brittle hair may also be observed. Increased frequency of bowel movements and diarrhea are other common symptoms. Those struggling with hyperthyroidism may experience severe fatigue and sleep problems. Thyroid gland enlargement, known as goiter, is often observed in the front of the neck. In some cases, such as Graves’ disease, the eyes may protrude and there may be increased sensitivity to light.
To diagnose hyperthyroidism, several tests are performed:
Blood Tests:
- Thyroid Function Tests
- Thyroid Antibody Tests
Imaging Tests:
- Thyroid Ultrasound
- Radioactive Iodine Uptake Test
- Thyroid Scan
These tests measure thyroid hormone and antibody levels to determine the presence and type of disease. Imaging methods such as ultrasound are used to evaluate the structural condition of the thyroid gland. The radioactive iodine test measures the iodine absorption capacity of the gland and visually maps thyroid activity.
How Do Thyroid Function Disorders Affect Metabolism?
Thyroid function disorders significantly affect metabolism and can lead to various health problems. Underactivity of the thyroid gland, known as hypothyroidism, slows metabolism. This slowing causes energy levels and body temperature to decrease. Hypothyroidism triggers the following symptoms:
- Weight gain
- Constipation
- Depression
- Increased sensitivity to cold
In contrast, hyperthyroidism accelerates metabolism. This increase speeds up calorie burning and raises body temperature. Symptoms associated with hyperthyroidism include:
- Weight loss
- Rapid heart rate
- Increased appetite
- Irritability
- Sweating
In both cases, there are profound effects on the body’s basic functions. Thyroid hormones regulate heart rate and the use of carbohydrates, fats, and proteins.
What Are the Long-Term Effects of Thyroid Diseases?
The long-term effects of thyroid diseases can lead to serious health problems, depending on whether the gland is underactive or overactive. In hypothyroidism, bodily functions slow down and negatively affect various systems:
Cardiovascular Issues:
High LDL cholesterol levels can trigger heart disease.
Mental Health:
Mental fog and depression are common emotional issues.
Neurological Problems:
Peripheral neuropathy can cause pain and numbness.
Reproductive Health:
Menstrual irregularities and fertility issues may occur.
Myxedema Coma:
A life-threatening condition characterized by extreme fatigue and hypothermia.
Hyperthyroidism, on the other hand, accelerates the body and causes different health problems:
Cardiovascular Complications:
Heart rhythm disturbances and tachycardia.
Bone Health:
Increased risk of osteoporosis.
Eye Problems:
Swelling of the eyes and vision problems may develop.
Skin and Hair Changes:
Thinning skin and weakened hair.
How Are Thyroid Hormone Imbalances Treated?
Thyroid hormone imbalances are classified as hypothyroidism and hyperthyroidism, each with different treatment approaches tailored to the patient’s condition.
In hypothyroidism, missing hormones are replaced synthetically:
- Synthetic thyroid hormones are used.
- These medications are taken orally, daily.
- Hormone levels are monitored regularly with blood tests.
- Dosage adjustments are made according to test results.
Hyperthyroidism treatment focuses on reducing the effects of excessive thyroid hormone:
- Antithyroid drugs are used to suppress thyroid hormone production.
- Beta-blockers are given to manage symptoms.
- Radioactive iodine therapy destroys overactive thyroid cells.
Depending on the patient’s situation, part or all of the thyroid gland may be removed, especially if other treatment options are insufficient or inappropriate.
How Do Thyroid Problems Affect Weight Gain or Loss?
The thyroid gland is a vital organ that directly affects the body’s metabolic rate. Whether the gland is underactive or overactive, it can cause significant changes in weight. In hypothyroidism—when too little thyroid hormone is produced—metabolic rate drops. This slows the body’s ability to burn calories and usually results in weight gain. This weight gain is mostly due to water and salt retention, including:
- Generally a weight gain of 5 to 10 pounds
- Weight gain is mainly from water retention
On the other hand, hyperthyroidism leads to a high metabolic rate. Excess thyroid hormones make the body burn more calories, which generally causes weight loss. However, this is also associated with increased appetite, and in some cases, high calorie needs may be balanced by increased intake. The extent of weight loss may include:
- Weight loss may range from mild to significant
- Increased metabolic rate triggers calorie burning
In both cases, proper medical intervention and hormonal adjustments can restore weight and metabolic balance to normal. However, post-treatment weight changes are usually limited and mostly due to water weight loss. Therefore, the state of the thyroid gland directly affects body weight and overall health.
Interventional Radiology and Neuroradiology Speaclist Prof. Dr. Özgür Kılıçkesmez graduated from Cerrahpaşa Medical Faculty in 1997. He completed his specialization at Istanbul Education and Research Hospital. He received training in interventional radiology and oncology in London. He founded the interventional radiology department at Istanbul Çam and Sakura City Hospital and became a professor in 2020. He holds many international awards and certificates, has over 150 scientific publications, and has been cited more than 1500 times. He is currently working at Medicana Ataköy Hospital.
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