Hypothyroidism is a medical condition in which the thyroid gland produces insufficient quantities of essential thyroid hormones—Triiodothyronine (T3) and Thyroxine (T4)—leading to a generalized slowing of body metabolism. It is more common in women and can range from mild subclinical cases to severe myxedema.
Causes of Hypothyroidism
- Hashimoto’s Thyroiditis (Autoimmune Disease): Most common cause; the body's immune system produces autoantibodies (anti-TPO) that destroy thyroid tissue.
- Iodine Deficiency: Dietary lack of iodine, which is essential for thyroid hormone synthesis.
- Post-Thyroid Surgery or Radiation Therapy: Partial/total thyroidectomy or radioactive iodine treatment for hyperthyroidism/thyroid cancer.
- Congenital Hypothyroidism: Infants born with an underdeveloped or absent thyroid gland.
- Pituitary Gland Dysfunction: Secondary hypothyroidism caused by inadequate TSH secretion from the pituitary gland.
- Medication-Induced: Drugs such as Lithium, Amiodarone, and interferon-alpha interfering with thyroid function.
Symptoms of Hypothyroidism
- General Physical Symptoms: Chronic fatigue, muscle weakness, unexplained weight gain (despite normal eating), cold intolerance (feeling cold when others are comfortable), dry rough skin, brittle hair & nails, puffy face, swollen hands/feet (myxedema).
- Mental & Cognitive Symptoms: Depression, mood swings, difficulty concentrating ("brain fog"), memory impairment, slow speech.
- Metabolic & Digestive Symptoms: Constipation, slow heart rate (bradycardia), hoarse voice, high cholesterol.
- Reproductive Symptoms: Irregular or heavy menstrual bleeding (menorrhagia), infertility, increased miscarriage risk.
- Severe Cases (Myxedema Crisis – Life-Threatening): Extreme hypothermia, severe bradycardia, hypoventilation, confusion, or myxedema coma (requires immediate emergency ICU care).
Diagnostic Evaluation
- Serum TSH (Thyroid-Stimulating Hormone): Elevated TSH is the primary sensitive marker for primary hypothyroidism.
- Free T4 (Thyroxine): Low Free T4 levels confirm overt hypothyroidism.
- Thyroid Autoantibodies (Anti-TPO, TgAb): High titers confirm Hashimoto's Thyroiditis.
- Thyroid Ultrasound: Evaluates goiter, thyroid nodules, or parenchymal echotexture.
Treatment & Management Protocol
1. Daily Hormone Replacement Therapy
- Levothyroxine (Synthroid, Eltroxin): Synthetic T4 hormone taken daily on an empty stomach with water (30–60 minutes before breakfast).
- Dose Titration: Blood TSH levels rechecked every 6–8 weeks until optimal dosage is established.
2. Dietary & Lifestyle Guidance
- Nutritional Support: Ensure adequate iodine, selenium, and zinc intake (nuts, seeds, seafood, eggs).
- Avoid Absorption Interferences: Do not take calcium, iron supplements, antacids, or soy products within 4 hours of levothyroxine. Avoid excessive raw goitrogenic vegetables (raw cabbage, broccoli).
- Regular Exercise: Helps combat weight gain, constipation, and muscle lethargy.
Complications (If Untreated)
- Goiter: Thyroid enlargement causing swallowing or breathing discomfort.
- Cardiovascular Disease: Elevated LDL cholesterol, pericardial effusion, and heart failure.
- Infertility & Developmental Delay: Maternal hypothyroidism can cause congenital birth defects or cognitive impairments in infants.
- Myxedema Coma: Fatal end-stage hypothyroid emergency.
