The thyroid is a small, butterfly-shaped gland located at the base of the neck below the Adam’s apple. It produces thyroid hormones that help regulate growth, development, metabolism and other important body functions. Thyroid disease refers to a group of disorders that affect the thyroid gland.
Some quick answers to common questions:
– Is thyroid disease common? Yes, thyroid disorders are very common, affecting around 12% of the population. Women are 5-8 times more likely to have thyroid problems compared to men.
– What are the main types of thyroid disease? The main types are hypothyroidism (underactive thyroid), hyperthyroidism (overactive thyroid), thyroid nodules and thyroid cancer.
– What are the symptoms? Symptoms can include fatigue, weight changes, constipation, increased sensitivity to cold, dry skin, hair loss, muscle aches, depression, irregular periods in women, and more.
– Is thyroid disease serious? Thyroid disease can range from mild to life-threatening if left untreated. However, most thyroid problems can be managed with proper treatment.
Causes and Risk Factors
There are various causes and risk factors for developing thyroid disorders:
– Autoimmune disease – The immune system attacks the thyroid gland, causing inflammation and impaired thyroid function. Hashimoto’s thyroiditis is the most common cause of hypothyroidism.
– Iodine deficiency or excess iodine – Iodine is needed to produce thyroid hormones. Too little or too much iodine can disrupt hormone production.
– Radiation exposure – Radiation treatment to the head, neck or chest can damage the thyroid.
– Genetics – A family history increases risk.
– Pregnancy – Thyroid problems occur more often in women after giving birth.
– Age – Thyroid disorders become more common with age.
– Gender – Women are much more likely to be affected.
– Other medical conditions – Diabetes, rheumatoid arthritis, lupus, celiac disease, and other conditions can increase risk.
– Medications – Drugs that interfere with thyroid function include lithium, amiodarone, interferon alpha, and more.
– Damage to the pituitary gland – The pituitary gland controls the thyroid, so damage to it can disrupt thyroid function.
– Too much or too little iodine intake
Types of Thyroid Disease
The major types of thyroid disease include:
Hypothyroidism
In hypothyroidism, the thyroid gland does not produce enough thyroid hormones. This slows metabolism and other body functions.
Causes include:
– Hashimoto’s thyroiditis – autoimmune destruction of the thyroid
– Treatment for hyperthyroidism – removal of part of the thyroid, or radioactive iodine therapy
– Radiation therapy – can damage thyroid cells
– Congenital hypothyroidism – babies born with an underactive thyroid
– Iodine deficiency
– Pituitary gland disorders
Symptoms include fatigue, weight gain, feeling cold, constipation, dry skin, depression, muscle weakness, and more.
Hyperthyroidism
Hyperthyroidism is when the thyroid gland is overactive and produces too much thyroid hormone. This speeds up metabolism.
Causes include:
– Grave’s disease – most common cause, autoimmune disorder
– Thyroid nodules – lumps in the thyroid that may overproduce hormones
– Inflammation (thyroiditis)
– Excess iodine intake
– Taking too much synthetic thyroid hormone medication
Symptoms include anxiety, fatigue, weight loss, rapid heartbeat, hand tremors, excessive sweating, diarrhea, and more.
Goiter
A goiter is an enlargement of the thyroid that causes a swelling in the front of the neck.
Causes include:
– Iodine deficiency – most common worldwide
– Hashimoto’s thyroiditis
– Graves’ disease
– Thyroid nodules
– Thyroid cancer
A large goiter may create a feeling of tightness in the throat, coughing, hoarseness, and trouble swallowing or breathing.
Thyroid Nodules
Thyroid nodules are lumps that form within the thyroid gland. They are usually benign but can sometimes be cancerous.
Risk factors include:
– Age over 50 years old
– Radiation exposure
– Family history
– Iodine deficiency
– Being female
Most nodules do not cause symptoms. Some may secrete excess thyroid hormones and cause hyperthyroidism. Large nodules may obstruct breathing or swallowing.
Thyroid Cancer
Thyroid cancer starts in the cells of the thyroid gland. It is uncommon compared to other cancers.
Types include:
– Papillary carcinoma – most common, usually grows slowly
– Follicular carcinoma
– Medullary carcinoma – can run in families
– Anaplastic carcinoma – rare, aggressive
Risk factors include being female, radiation exposure, family history, and certain genetic syndromes.
Symptoms can include a lump or swelling in the neck, hoarseness, difficulty swallowing, and swollen lymph nodes. Treatment involves surgery, radioactive iodine therapy, thyroid hormone therapy, radiation, chemotherapy, or targeted therapy.
Thyroiditis
Thyroiditis refers to inflammation of the thyroid gland, usually due to an autoimmune attack. This can cause thyroid hormones to leach out into the blood initially, causing hyperthyroidism, followed by a hypothyroid phase as hormone reserves get depleted.
Types include:
– Hashimoto’s thyroiditis – chronic autoimmune inflammation leading to hypothyroidism
– Postpartum thyroiditis – occurs after pregnancy
– Subacute thyroiditis – painful inflammation, often following a viral infection
– Drug-induced thyroiditis – inflammation triggered by a medication
– Trauma-induced thyroiditis – inflammation after physical injury to thyroid
Symptoms depend on the phase and type of thyroiditis. Overall, it often goes through an initial hyperthyroid phase with symptoms like anxiety, weight loss, rapid heartbeat, and difficulty sleeping. This transitions into a hypothyroid phase with fatigue, weight gain, feeling cold, and muscle weakness.
Diagnosis
Thyroid disorders are diagnosed through a medical history, physical exam, blood tests, and imaging:
– Physical exam – The doctor looks for enlargement or nodules in the thyroid gland and signs of hypothyroidism or hyperthyroidism.
– Blood tests – Blood levels of thyroid hormones (TSH, T4, T3) are measured. This helps diagnose hyperthyroidism or hypothyroidism. Autoimmune markers may also be tested.
– Ultrasound – An ultrasound uses sound waves to create images of the thyroid to identify nodules, inflammation, tumors, etc.
– Radioiodine scan – Patients swallow a radioactive iodine solution which is taken up by thyroid cells. Abnormal cells like tumors show up on the scan.
– Biopsy – A needle biopsy of a nodule may be done to test for cancer cells.
Other tests like an MRI, CT scan, or thyroid nuclear scan may be used in some cases.
Complications
Untreated thyroid disease can lead to serious complications:
Hypothyroidism complications:
– Goiter
– Heart problems – increased risk of heart failure and heart attacks
– Mental health issues – depression, dementia
– Peripheral neuropathy – nerve damage causing numbness and tingling
– Myxedema coma – intensive hypothyroidism leading to life-threatening coma
– Birth defects – in babies born to mothers with untreated hypothyroidism
Hyperthyroidism complications:
– Irregular heartbeat – potential atrial fibrillation increasing stroke risk
– Heart failure
– Brittle bones – thyroid hormones increase bone turnover
– Thyroid storm – extremely high thyroid hormone levels become life-threatening
Goiter complications:
– Difficulty breathing or swallowing for large goiters
– Hoarseness or coughing due to pressure on windpipe
Thyroid nodules and cancer complications:
– Difficulty breathing or swallowing
– Spread of cancerous cells to other organs like lymph nodes, lungs, liver, bones (metastasis)
Treatment
Treatment depends on the specific type and cause of thyroid disorder:
Hypothyroidism treatment:
– Levothyroxine (synthroid, levoxyl) – daily oral thyroid hormone replacement medication
– Proper dosage to restore thyroid hormone levels
– Lifelong treatment, with regular monitoring of TSH levels
– Treatment of underlying autoimmune disease if due to Hashimoto’s
Hyperthyroidism treatment:
– Antithyroid drugs – methimazole, propylthiouracil to block excess hormone production
– Radioactive iodine – destroys overactive thyroid cells
– Surgery – removal of thyroid, or part of thyroid
– Beta blockers – control symptoms like rapid heart rate
Goiter treatment:
– Radioactive iodine
– Surgery to remove part or all of enlarged thyroid
– Thyroid hormone replacement if it causes hypothyroidism
Thyroid nodules and cancer treatment:
– Surgery to remove nodules or thyroid cancer
– Radioactive iodine to destroy remaining thyroid cells
– Thyroid hormone therapy
– External radiation
– Chemotherapy
– Targeted therapy for advanced cancers
Treatment aims to return thyroid function to normal levels, manage symptoms, remove cancerous tissue, and prevent complications.
Outlook and Prognosis
With proper treatment, most thyroid problems can be managed effectively:
– Hypothyroidism – Patients treated with thyroid hormone replacements can manage their condition throughout life with regular monitoring and dose adjustments. The prognosis is excellent.
– Hyperthyroidism – Antithyroid drugs, radioactive iodine, or surgery can often permanently correct hyperthyroidism. Relapse occurs in about 30% of patients. With treatment, most patients lead normal lives.
– Goiter – Most goiters respond well to radioactive iodine treatment. Surgery successfully removes large goiters. Prognosis is good with treatment.
– Thyroid nodules – The vast majority of nodules are non-cancerous. Only about 5% are malignant. Benign nodules are usually left alone or removed if causing problems. Cancerous nodules are treated with surgery and have a good prognosis when found early before spreading.
– Thyroid cancer – For localized thyroid cancers detected early, the 10-year survival rate is 97-98%. However, anaplastic thyroid cancer has a poor prognosis. With proper treatment, many patients achieve long-term remission.
Overall, most thyroid problems are very manageable if treated. Patients can expect to live a normal lifespan. Close follow up and monitoring is key to preventing recurrence and complications.
Prevention
While thyroid disease can’t always be prevented, the following practices may lower risk:
– Ensure adequate iodine intake from foods like seafood, eggs, dairy, grains, and iodized salt. Too little (or too much) iodine impacts thyroid function.
– Have any lumps or growths on the neck evaluated promptly, since early treatment of thyroid cancer leads to better outcomes.
– Avoid excess radiation exposure to the head, neck or chest. Use protective shields and equipment as appropriate.
– For autoimmune thyroid disease, work with your doctor to manage triggers. Get regular TSH checks done.
– Don’t smoke and avoid secondhand smoke – this increases thyroid cancer risk.
– Discuss any family history of thyroid disease with your doctor and appropriate monitoring.
– Women should have thyroid levels evaluated routinely before and after pregnancy.
– Be cautious with thyroid hormone replacement dosage and work with your provider to find the optimal dose.
– Speak to your doctor about any symptoms you’re experiencing to determine appropriate thyroid testing.
Conclusion
Thyroid disorders are very common, but often manageable with the right treatment and monitoring. Hypothyroidism and hyperthyroidism usually respond well to medications, radioactive iodine, or surgery. Thyroid enlargements like goiter may improve with iodine treatment or surgery if severe. Thyroid cancer is fairly rare and highly treatable when detected early. While thyroid disease can potentially become serious if untreated, patients who receive appropriate long-term care can expect an excellent outcome and normal life expectancy. Staying attuned to your body, getting regular checkups, and discussing any thyroid-related family history with your doctor can go a long way in preventing complications.