Overview#
Hypothyroidism is a condition where the thyroid gland does not produce enough thyroid hormones (T3 and T4), slowing the body's metabolism. It is extremely common in India, affecting an estimated 11 % of the population, with a higher prevalence among women. Subclinical hypothyroidism – mildly elevated TSH with normal T4 – is even more widespread. Hashimoto's thyroiditis (an autoimmune disorder) is the most common cause.
Causes & Risk Factors#
- Hashimoto's thyroiditis – autoimmune destruction of thyroid tissue; the most frequent cause in iodine-sufficient areas.
- Iodine deficiency – still a concern in certain regions of India despite universal salt iodization programmes.
- Post-surgical or post-radioactive iodine treatment – thyroid removal or ablation for hyperthyroidism or cancer.
- Medications – lithium, amiodarone, and certain anti-cancer drugs can impair thyroid function.
- Women aged 30-50 are disproportionately affected; risk increases during pregnancy and after menopause.
Signs & Symptoms#
- Unexplained weight gain and difficulty losing weight
- Persistent fatigue and lethargy
- Cold intolerance – feeling cold when others are comfortable
- Dry skin, brittle nails, and hair loss (especially outer third of eyebrows)
- Constipation
- Puffiness around the face and eyes (myxoedema)
- Muscle aches, joint stiffness
- Irregular or heavy menstrual periods in women
Diagnosis#
Thyroid function tests are the cornerstone of diagnosis:
- TSH (Thyroid Stimulating Hormone) – elevated TSH (> 4.5 mIU/L) is the earliest marker. Book Thyroid Profile
- Free T4 (FT4) – low FT4 with high TSH confirms primary hypothyroidism.
- Anti-TPO antibodies – elevated in Hashimoto's thyroiditis, helping identify the autoimmune cause.
- Lipid Profile – hypothyroidism frequently causes elevated cholesterol. Book Lipid Profile
Treatment Options#
Levothyroxine (T4 replacement) is the standard treatment. It is taken once daily on an empty stomach, 30-60 minutes before breakfast. Dose is adjusted based on TSH levels checked every 6-8 weeks initially, then every 6-12 months once stable.
Lifestyle tips:
- Take levothyroxine with plain water; avoid calcium, iron supplements, and tea/coffee for at least 1 hour after the dose.
- Include selenium-rich foods like Brazil nuts, eggs, and mushrooms which support thyroid function.
- Regular exercise helps combat fatigue and weight gain.
Prevention#
- Ensure adequate iodine intake through iodized salt (most Indian households already use this).
- Women planning pregnancy should get TSH tested as untreated hypothyroidism can affect fetal brain development.
- If you have a family history of thyroid disorders, get screened annually starting at age 25.
- Avoid excessive consumption of raw cruciferous vegetables (cabbage, cauliflower) in large amounts if iodine intake is borderline.
When to See a Doctor#
Consult a doctor if you experience persistent unexplained weight gain, constant fatigue, hair loss, or menstrual irregularities. Pregnant women with a TSH > 2.5 mIU/L in the first trimester should be treated promptly. Seek urgent care for symptoms of myxoedema crisis: extreme drowsiness, hypothermia, and confusion – this is a medical emergency.