14 Thyroid Disease

Thyroid Disease

The thyroid gland, located in the neck, produces hormones that regulate metabolism, energy production, and growth. Thyroid diseases, including hypothyroidism and hyperthyroidism, result from the overproduction or underproduction of thyroid hormones.

1. Hypothyroidism
   • Pathophysiology: Hypothyroidism occurs when the thyroid gland produces insufficient thyroid hormones (thyroxine [T4] and triiodothyronine [T3]), leading to a slowdown in metabolic processes. The most common cause is Hashimoto’s thyroiditis, an autoimmune disorder where the immune system attacks the thyroid gland.
   • Clinical Manifestations:
     • Fatigue and Weakness: Due to decreased metabolic rate and energy production.
     • Weight Gain: Often occurs despite no change in diet or exercise, due to a slowed metabolism.
     • Cold Intolerance: Patients with hypothyroidism may feel excessively cold.
     • Bradycardia: Slowed heart rate is common in hypothyroidism.
     • Constipation: A slowed digestive process can lead to constipation.
     • Dry Skin and Hair: Reduced oil production by the skin can lead to dryness, and hair may become brittle.
   • Diagnosis: Hypothyroidism is diagnosed through elevated thyroid-stimulating hormone (TSH) levels and low free T4 levels in the blood.
   • Management:
     • Thyroid Hormone Replacement: The standard treatment is levothyroxine, a synthetic form of T4, which normalizes thyroid hormone levels and alleviates symptoms.
     • Regular Monitoring: Patients require regular monitoring of TSH levels to ensure the correct dosage of medication.
2. Hyperthyroidism
   • Pathophysiology: Hyperthyroidism occurs when the thyroid gland produces excessive thyroid hormones, leading to an accelerated metabolic rate. The most common cause is Graves’ disease, an autoimmune disorder where antibodies stimulate the thyroid to produce too much hormone.
   • Clinical Manifestations:
     • Weight Loss: Despite normal or increased appetite, patients with hyperthyroidism may lose weight due to increased metabolism.
     • Heat Intolerance: Patients often feel excessively warm and may sweat more than usual.
     • Tachycardia and Palpitations: Increased heart rate and palpitations are common symptoms.
     • Nervousness and Anxiety: Due to increased stimulation of the nervous system.
     • Tremors: Fine tremors of the hands can occur.
     • Exophthalmos: Protrusion of the eyes, commonly seen in Graves’ disease.
   • Diagnosis: Hyperthyroidism is diagnosed through low TSH levels and elevated free T4 and T3 levels. Thyroid uptake scans and antibody testing may be used to identify the underlying cause.
   • Management:
     • Antithyroid Medications: Such as methimazole or propylthiouracil (PTU) to reduce thyroid hormone production.
     • Radioactive Iodine Therapy: Used to destroy overactive thyroid cells, leading to a decrease in hormone production.
     • Surgical Intervention: Thyroidectomy, the removal of the thyroid gland, may be necessary in severe cases.
     • Beta-Blockers: Used to control symptoms such as tachycardia and tremors.