Hyperthyroidism is a condition in which the thyroid gland produces an excess of thyroid hormones (T3 and T4), leading to a hypermetabolic state. It causes rapid weight loss, elevated heart rate, anxiety, tremors, and heat intolerance.
Causes of Hyperthyroidism
- Graves' Disease (Most Common): Autoimmune disorder where Thyroid-Stimulating Immunoglobulins (TSI) bind to and overstimulate TSH receptors.
- Toxic Multinodular Goiter (Plummer’s Disease): Thyroid nodules independently hypersecreting T3/T4.
- Thyroiditis (Thyroid Inflammation): Viral infection or postpartum inflammation releasing stored thyroid hormones into blood.
- Excessive Iodine Intake: High iodine exposure from amiodarone, contrast agents, or kelp supplements (Jod-Basedow phenomenon).
- Levothyroxine Overdose: Excessive exogenous thyroid hormone replacement therapy.
Symptoms of Hyperthyroidism
- Metabolic Symptoms: Unintentional rapid weight loss despite increased appetite, excessive sweating, heat intolerance, warm moist skin.
- Cardiovascular & Nervous Symptoms: Tachycardia (fast heart rate > 100 bpm), palpitations, atrial fibrillation, tremors (fine hand shaking), anxiety, irritability, severe insomnia.
- Digestive Symptoms: Frequent bowel movements or persistent diarrhea.
- Eye & Skin Symptoms (Graves' Specific): Exophthalmos (bulging eyes), eye grittiness, double vision, pretibial myxedema (swollen red shins).
- Reproductive Symptoms: Light or irregular menstrual cycles, reduced fertility in women, gynecomastia in men.
- Severe Complication (Thyroid Storm): Life-threatening crisis marked by high fever (> 104°F), severe tachycardia, agitation, delirium, and heart failure.
Diagnostic Workup
- Serum TSH Test: Suppressed/low TSH (< 0.1 mIU/L).
- Free T4 & Free T3 Blood Tests: Significantly elevated hormone levels.
- Thyroid Autoantibody Tests: TSH Receptor Antibodies (TRAb) / TSI positive in Graves' disease.
- Radioactive Iodine Uptake (RAIU) Test: Differentiates Graves' (diffuse high uptake) from thyroiditis (low uptake) or toxic nodules (nodular uptake).
- Thyroid Ultrasound: Visualizes nodules, goiter vascularity, and tissue architecture.
Treatment Modalities
- 1. Antithyroid Medications: Methimazole (MMI) or Propylthiouracil (PTU) block thyroid hormone synthesis.
- 2. Beta-Blockers (e.g., Propranolol, Atenolol): Rapidly alleviates heart palpitations, tremors, hypertension, and anxiety.
- 3. Radioactive Iodine (RAI-131) Therapy: Ablative treatment destroying hyperactive thyroid follicular cells.
- 4. Surgical Thyroidectomy: Partial or total thyroidectomy indicated for large goiters, malignancy, or medication intolerance.
Complications & Prevention
Untreated hyperthyroidism causes cardiac arrhythmias, heart failure, osteoporosis (rapid bone loss), and thyroid storm. Regular monitoring, stress control, and avoiding excess iodine supplements are critical.
