ICD-10 · E03.9
Hypothyroidism
Hypothyroidism means the thyroid gland produces too little thyroid hormone, slowing the body's metabolism. It is strikingly common in India, particularly among women over 35, and is easily treated once identified.
Symptoms
Fatigue, weight gain despite unchanged diet, cold intolerance, dry skin, hair fall, constipation, puffiness of the face, heavy or irregular periods, low mood and poor concentration.
Causes & risk factors
Autoimmune Hashimoto's thyroiditis is the leading cause. Others include iodine deficiency, thyroid surgery, radioactive iodine treatment, certain drugs such as lithium and amiodarone, and postpartum thyroiditis.
Diagnosis
A raised TSH with a low free T4 confirms overt hypothyroidism; a raised TSH with normal T4 is subclinical. Anti-TPO antibodies indicate an autoimmune cause. Testing should be done fasting and before the day's levothyroxine dose.
Treatment options
Levothyroxine taken once daily on an empty stomach, 30–60 minutes before breakfast, with the dose adjusted every 6–8 weeks based on TSH. Calcium, iron and antacids must be taken at least four hours apart because they block absorption. Treatment is usually lifelong, and the brand should not be switched casually since potency can vary slightly.
When to see a doctor
Palpitations, tremor or weight loss on treatment (a sign of over-replacement), a growing neck swelling, difficulty swallowing, severe drowsiness, or planning a pregnancy — dose needs review early.