Hyperthyroidism
Hyperthyroidism occurs when the thyroid gland produces too much thyroid hormone, speeding up the body's metabolism. Common features include weight loss, rapid heartbeat, anxiety, and heat intolerance.
Table of Contents
Quick Facts
- Type: Endocrine disorder
- ICD-10: E05
- Most common cause: Graves' disease
- More common in: Women
Overview
The thyroid is a butterfly-shaped gland at the front of the neck. It produces hormones (T3 and T4) that regulate metabolism. In hyperthyroidism, the gland makes too much of these hormones, which speeds up many body functions.
The most common cause is Graves' disease, an autoimmune disorder in which antibodies stimulate the thyroid to overproduce hormones.
Symptoms
- Unintentional weight loss despite normal or increased appetite
- Rapid heartbeat, palpitations, or atrial fibrillation
- Anxiety, nervousness, irritability
- Heat intolerance and excessive sweating
- Tremor, especially of the hands
- Difficulty sleeping
- Fatigue and muscle weakness
- Frequent bowel movements or diarrhea
- Menstrual changes (lighter, less frequent periods)
- Eye changes in Graves' disease (bulging, dryness, redness)
- Enlarged thyroid (goiter)
Causes
- Graves' disease — autoimmune stimulation of the thyroid (most common cause)
- Toxic multinodular goiter — overactive nodules producing excess hormone
- Toxic adenoma — a single overactive thyroid nodule
- Thyroiditis — inflammation that releases stored hormone
- Excess iodine intake or contrast dye
- Excess thyroid hormone medication
Risk Factors
- Female sex (much more common in women)
- Family history of thyroid disease
- Personal history of autoimmune disease
- Recent pregnancy
- Smoking (especially for Graves' eye disease)
Diagnosis
- Blood tests — low TSH (thyroid-stimulating hormone), elevated T4 and/or T3
- Thyroid antibodies (TRAb, TPO) to identify Graves' disease
- Radioactive iodine uptake scan to identify cause
- Thyroid ultrasound for nodules
Treatment
Antithyroid medications
Methimazole or propylthiouracil reduce hormone production. They can lead to long-term remission in some Graves' disease patients.
Radioactive iodine
A single oral dose destroys overactive thyroid tissue. Most patients eventually need thyroid hormone replacement afterward.
Surgery (thyroidectomy)
Removal of part or all of the thyroid, especially for large goiters, pregnant patients who can't take antithyroid drugs, or those with severe eye disease.
Beta-blockers
Used to control symptoms such as rapid heartbeat and tremor while definitive treatment takes effect.
When to See a Doctor
See a doctor for unexplained weight loss, palpitations, persistent anxiety, heat intolerance, or any neck swelling.
Seek emergency care for a 'thyroid storm' — extreme symptoms including high fever, very fast heartbeat, confusion, and severe weakness. This is a life-threatening emergency.
Frequently Asked Questions
Hyperthyroidism is highly treatable. Antithyroid medications can induce remission in some people; radioactive iodine or surgery provides a permanent cure but usually leads to hypothyroidism requiring lifelong hormone replacement.
Graves' disease is the most common cause of hyperthyroidism, but they are not the same. Hyperthyroidism is the state of an overactive thyroid; Graves' is a specific autoimmune condition that produces it.
Yes — atrial fibrillation, heart palpitations, and increased risk of heart failure are well-recognized complications. Symptoms usually improve when the thyroid is treated.
Many people gain back the weight they lost during hyperthyroidism after treatment. Some gain more, especially if they become hypothyroid; managing thyroid hormone replacement properly helps.
References
- American Thyroid Association. Hyperthyroidism Patient Brochure.
- Endocrine Society. Hyperthyroidism Diagnosis and Management Guideline.