Hypothyroidism

Underactive Thyroid (Hypothyroidism): Complete Guide with FAQs

Introduction

• Hypothyroidism, or underactive thyroid, is a condition where the thyroid gland does not produce enough thyroid hormones to meet the body’s needs.
• It can lead to symptoms such as fatigue, weight gain, cold intolerance, and depression.
• Common causes include autoimmune diseases like Hashimoto’s thyroiditis, iodine deficiency, and certain medications.

Causes of Hypothyroidism

• Autoimmune conditions (e.g., Hashimoto’s thyroiditis).
• Iodine deficiency or excess.
• Post-thyroidectomy (surgical removal of the thyroid gland).
• Radiation therapy to the neck or head.
• Certain medications (e.g., lithium, amiodarone).
• Congenital hypothyroidism (present at birth).
• Pituitary or hypothalamic dysfunction (secondary hypothyroidism).

Symptoms

• Fatigue and low energy levels.
• Weight gain despite no change in appetite.
• Sensitivity to cold temperatures.
• Dry skin and hair, hair thinning.
• Constipation.
• Depression or low mood.
• Hoarseness.
• Puffy face and swelling in the extremities.
• Slow heart rate.
• Menstrual irregularities or heavy periods.

Diagnosis

• Thyroid Function Tests (TFTs):
  • Elevated TSH (thyroid-stimulating hormone).
  • Low free T4 (thyroxine) levels.
• Antibody Tests: Detect anti-thyroid antibodies in autoimmune hypothyroidism (e.g., TPO antibodies).
• Imaging: Ultrasound of the thyroid gland in certain cases.

Treatment

Thyroid Hormone Replacement Therapy

• Levothyroxine: Synthetic thyroid hormone that replaces T4.
  • Typical starting dose: 25–75 mcg daily, adjusted based on TSH levels and clinical response.
  • Taken on an empty stomach, at least 30–60 minutes before breakfast.

Lifestyle Modifications

• Balanced diet rich in iodine, selenium, and zinc (important for thyroid function).
• Regular exercise to improve energy levels and metabolism.
• Avoiding excessive intake of goitrogenic foods like raw cruciferous vegetables.

Complications of Untreated Hypothyroidism

• Goiter (enlarged thyroid gland).
• Cardiovascular issues (e.g., high cholesterol, heart disease).
• Infertility.
• Myxedema (severe hypothyroidism), which can lead to life-threatening coma.
• Depression and cognitive impairment.

Monitoring and Follow-Up

• Regular TSH and T4 tests to ensure proper dosing of levothyroxine.
• Monitoring for symptoms of over-treatment (e.g., palpitations, weight loss).
• Annual thyroid function tests for stable patients.

Patient Counseling Points

• Take levothyroxine as prescribed, on an empty stomach, for optimal absorption.
• Avoid taking iron or calcium supplements within 4 hours of thyroid medication.
• Report symptoms of hyperthyroidism (e.g., rapid heart rate, sweating) to your doctor.
• Maintain regular follow-up appointments to monitor thyroid function.
• Practice a healthy lifestyle to support overall well-being.

Use in Children

• Congenital hypothyroidism requires early treatment to prevent developmental delays.
• Levothyroxine doses are weight-based and adjusted with growth.

Use in Pregnancy

• Untreated hypothyroidism during pregnancy can cause complications like preeclampsia and low birth weight.
• Pregnant women may need increased levothyroxine doses to maintain normal thyroid function.

Use in Elderly

• Start with lower doses of levothyroxine to avoid strain on the heart.
• Monitor closely for signs of over-treatment, such as atrial fibrillation or bone loss.

FAQs About Underactive Thyroid

Q1: What causes hypothyroidism?

• The most common cause is Hashimoto’s thyroiditis, an autoimmune condition. Other causes include iodine deficiency, thyroid surgery, and radiation therapy.

Q2: How is hypothyroidism diagnosed?

• Through blood tests measuring TSH and free T4 levels, and sometimes antibody tests for autoimmune causes.

Q3: Can hypothyroidism be cured?

• While it cannot be cured, it can be effectively managed with lifelong thyroid hormone replacement therapy.

Q4: What is levothyroxine?

• Levothyroxine is a synthetic form of T4, the primary treatment for hypothyroidism.

Q5: How long does it take to feel better after starting treatment?

• Most patients start to feel better within 2–4 weeks, but full symptom resolution may take months.

Q6: Can diet affect thyroid function?

• Yes, iodine, selenium, and zinc are crucial for thyroid health. Avoid excessive consumption of goitrogenic foods like raw cabbage or kale.

Q7: Can hypothyroidism cause weight gain?

• Yes, it can slow metabolism, leading to weight gain. Treatment helps regulate metabolism.

Q8: What happens if hypothyroidism is untreated?

• Untreated hypothyroidism can lead to complications such as goiter, heart problems, infertility, and in severe cases, myxedema coma.

Q9: Is hypothyroidism common during pregnancy?

• Yes, pregnancy can increase the demand for thyroid hormones, making hypothyroidism more common.

Q10: Can hypothyroidism cause depression?

• Yes, low thyroid hormone levels can lead to symptoms of depression or low mood.

Q11: Should I avoid certain foods if I have hypothyroidism?

• Avoid excessive intake of soy, raw cruciferous vegetables, and processed foods high in iodine.

Q12: Can hypothyroidism run in families?

• Yes, autoimmune thyroid disorders like Hashimoto’s thyroiditis often have a genetic component.

Q13: Can hypothyroidism affect my skin and hair?

• Yes, it can cause dry skin, brittle hair, and hair thinning.

Q14: How often should thyroid function tests be done?

• Every 6–8 weeks after starting or adjusting treatment, then every 6–12 months once stable.

Q15: Is it safe to take thyroid medication with other medications?

• Certain medications, such as calcium and iron supplements, can interfere with levothyroxine absorption. Take them at least 4 hours apart.

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