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 Hypothyroidism is a condition in which the thyroid gland does not produce enough thyroid hormones (primarily T4 and T3), which are essential for regulating metabolism, temperature, heart rate, and many other bodily functions. It’s the opposite of hyperthyroidism (overactive thyroid).
Who Can Have Hypothyroidism?
Anyone can develop it, but it is most common in:
Women, especially over age 40
People with a family history of thyroid disease
Individuals with autoimmune conditions
Those who’ve had radiation to the neck, thyroid surgery, or radioactive iodine treatment
New mothers (postpartum thyroiditis)
The elderly
Hypothyroidism as an Autoimmune Disease
In many cases, hypothyroidism is caused by autoimmune thyroiditis, mainly Hashimoto’s thyroiditis, where the immune system attacks the thyroid gland.
Associated Autoimmune Conditions:
Type 1 diabetes
Celiac disease
Rheumatoid arthritis
Vitiligo
Pernicious anemia
Lupus (SLE)
Addison’s disease
Causes of Hypothyroidism
Autoimmune disease (Hashimoto’s) – most common in developed countries
Iodine deficiency – most common globally
Thyroid surgery or radiation therapy
Medications: lithium, amiodarone, interferon
Congenital hypothyroidism
Pituitary disorders (central hypothyroidism)
Postpartum thyroiditis
Subacute thyroiditis or silent thyroiditis (can progress to permanent hypothyroidism)
Symptoms of Hypothyroidism
Fatigue, sluggishness
Weight gain despite poor appetite
Cold intolerance
Dry skin, brittle nails
Hair thinning or hair loss
Depression, memory issues (“brain fog”)
Constipation
Menstrual irregularities or infertility
Puffy face, hoarseness
Bradycardia (slow heart rate)
Myxedema (in advanced cases)
Can Thyroiditis Cause Hypothyroidism?
Yes. Thyroiditis, especially Hashimoto’s, often destroys thyroid tissue over time, leading to permanent hypothyroidism. Other forms (postpartum, subacute) may cause transient hypothyroidism or progress to permanent disease.
Tests to Diagnose Hypothyroidism
1. TSH (Thyroid-Stimulating Hormone): First-line test. High TSH suggests primary hypothyroidism.
2. Free T4 (Thyroxine): Low in true hypothyroidism.
3. Anti-TPO antibodies: Present in Hashimoto’s thyroiditis.
4. Thyroid ultrasound: If nodules or enlargement is suspected.
Tests for Follow-Up in Treated Patients
For patients on levothyroxine:
Monitor TSH every 6–12 weeks after dose adjustment, then every 6–12 months when stable.
Monitor Free T4 in special cases (central hypothyroidism, pregnancy).
Adjust dose for weight changes, aging, pregnancy, or new medications.
Social Media Myths vs Medical Truths
Myth Medical Fact
You can cure hypothyroidism with diet or supplements Most hypothyroidism is permanent and needs lifelong treatment
Natural thyroid (desiccated) is better than synthetic Levothyroxine is safe, consistent, and first-line therapy
Iodine supplements help everyone Excess iodine can worsen autoimmune thyroiditis
All fatigue and weight gain are from thyroid Many other conditions can cause these; always test TSH
Hypothyroidism causes cancer No direct link, but nodules should be evaluated
Can Hypothyroidism Become Cancer?
Hypothyroidism itself doesn’t become cancer.
However, Hashimoto’s thyroiditis may slightly increase the risk of thyroid nodules or papillary thyroid cancer, but overall risk remains low.
Treatment Options
1. Medical
Levothyroxine (T4 replacement): Daily oral tablet, taken on an empty stomach.
Liothyronine (T3): Rarely used except in combination or special cases.
2. Surgical
Rarely indicated unless:
Large goiter causing compression
Suspicion or confirmation of cancer
Cosmetic disfigurement
3. Radioactive iodine or antithyroid drugs
Not used for hypothyroidism — used in hyperthyroidism.
Prognosis
Excellent if treated properly.
Most patients live normal lives with normal life expectancy.
Untreated, it may lead to severe complications.
Complications of Untreated Hypothyroidism
Goiter (thyroid enlargement)
Infertility, miscarriages
Heart problems (bradycardia, pericardial effusion, heart failure)
High cholesterol and atherosclerosis
Myxedema coma: life-threatening crisis with hypothermia, hypotension, and mental status changes
What Is a Hypothyroid Crisis (Myxedema Coma)?
A rare but deadly emergency, typically in elderly or untreated patients, triggered by:
Infections
Surgery
Cold exposure
Sedatives
Symptoms:
Hypothermia
Severe lethargy or coma
Respiratory depression
Low heart rate, blood pressure, and sodium
Requires ICU care, IV levothyroxine, and steroids.

Raulayalamd@mydoctoroncall.com