Hypothyroidism – Symptoms and Causes
Overview
Hypothyroidism occurs when the thyroid gland produces insufficient thyroid hormone, also known as an underactive thyroid. Early stages of this condition often show no obvious symptoms.
However, untreated hypothyroidism can eventually cause serious health complications, including elevated cholesterol levels and heart issues.
Doctors diagnose hypothyroidism through blood testing. Treatment typically involves thyroid hormone medication. This treatment is generally straightforward and effective once the proper dosage is established for each patient.
Most patients can manage hypothyroidism successfully with proper medical supervision and consistent medication.
Signs and Symptoms
Hypothyroidism symptoms often develop slowly over several years. In the early stages, symptoms like tiredness and weight gain might seem like normal aging. As your metabolism slows further, more noticeable problems may appear.
Common symptoms include:
- Feeling tired often
- Being more sensitive to cold
- Hard or infrequent bowel movements
- Dry skin
- Weight gain
- Swelling in the face
- Voice changes (hoarseness)
- Rough skin and hair
- Weak muscles
- Muscle pain and stiffness
- Heavier or irregular periods
- Hair loss
- Slow heartbeat
- Feeling sad or depressed
- Trouble remembering things
Babies with Underactive Thyroid
Babies born with a missing or poorly working thyroid gland may not show symptoms right away. Without treatment, these signs may develop:
- Trouble feeding
- Slow growth
- Poor weight gain
- Yellow skin and eyes (jaundice)
- Constipation
- Weak muscle tone
- Dry skin
- Hoarse crying
- Larger than normal tongue
- Bulge near the belly button (umbilical hernia)
Even mild cases of untreated hypothyroidism in babies can lead to serious physical and mental development issues.
Young Children and Teenagers with Thyroid Problems
Children and teens with hypothyroidism often have symptoms like adults. They may also experience:
- Slow growth leading to shorter height
- Delayed tooth development
- Late puberty
- Poor mental development
When to Talk to a Doctor
Visit your doctor if you feel tired without reason or have other hypothyroidism symptoms.
If you already take thyroid medication, follow your doctor’s advice about checkups. At first, you’ll need regular appointments to ensure you’re taking the right dose.
Later, you’ll need checkups so your doctor can monitor your condition and adjust your medication if needed.
Causes
When the thyroid gland doesn’t produce enough hormones, hypothyroidism develops. This small, butterfly-shaped gland sits at the base of the neck below the Adam’s apple.
It makes two key hormones—thyroxine (T-4) and triiodothyronine (T-3)—that affect every body cell, controlling metabolism, body temperature, heart rate, and protein production.
Several conditions can lead to hypothyroidism:
Autoimmune Disease
Hashimoto’s disease is the most common cause of hypothyroidism. In this autoimmune condition, the body’s immune system creates antibodies that attack the thyroid tissue, reducing its ability to produce hormones.
Surgical Intervention
Removing part or all of the thyroid gland through surgery can significantly decrease or completely stop hormone production.
Radiation Exposure
Treatment for head and neck cancers using radiation therapy can damage the thyroid gland, leading to reduced function.
Thyroid Inflammation
Thyroiditis, or inflammation of the thyroid gland, can result from infections or autoimmune disorders. This condition can cause the thyroid to release all its hormones at once, leading to temporary hyperthyroidism, followed by a period of low activity.
Medication Effects
Some medications can interfere with thyroid function. Lithium, used to treat certain psychiatric conditions, is a notable example that may cause hypothyroidism.
Less common causes include:
Congenital Issues – Some babies are born with an underdeveloped or absent thyroid gland. Most states require newborn thyroid screening because symptoms aren’t always noticeable at birth.
Pituitary Problems – When the pituitary gland fails to produce enough thyroid-stimulating hormone (TSH), often due to benign tumors, the thyroid doesn’t receive proper signals to make hormones.
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Pregnancy-Related – Hypothyroidism can develop during or after pregnancy. Untreated, it increases the risks of:
- Miscarriage
- Premature birth
- Preeclampsia (dangerous high blood pressure in late pregnancy)
- Fetal development issues
Iodine Deficiency or Excess
The thyroid requires iodine to produce hormones. While deficiency is rare in the United States due to iodized salt, it remains common in other parts of the world. Too much iodine can worsen existing hypothyroidism.
| Risk Factor | How It Affects Thyroid Function |
|---|---|
| Autoimmune disease | Immune system attacks thyroid tissue |
| Surgery | Reduces or eliminates hormone-producing tissue |
| Radiation | Damages thyroid cells and function |
| Inflammation | Disrupts normal hormone production cycle |
| Certain medications | Interfere with hormone synthesis or release |
| Congenital problems | Thyroid doesn’t develop properly before birth |
| Pituitary dysfunction | Reduces signals telling thyroid to produce hormones |
| Pregnancy | Changes hormone needs and immune function |
| Iodine imbalance | Affects basic building blocks of thyroid hormones |
Risk Factors
Several factors can raise your chance of developing hypothyroidism:
- Gender: Women face a higher risk than men.
- Genetics: Having family members with thyroid problems increases the risk.
- Autoimmune conditions: Conditions like type 1 diabetes or celiac disease.
- Previous treatments: Past hyperthyroidism treatment
- Radiation exposure: Previous radiation to the neck or chest area.
- Surgical history: Prior thyroid surgery
Health Complications
Untreated hypothyroidism can lead to several serious health issues. Understanding these potential complications can help people seek timely treatment.
Enlarged Thyroid (Goiter)
When hypothyroidism remains untreated, the thyroid gland may grow larger, forming a goiter. This enlargement can cause difficulty swallowing, breathing problems, and discomfort in the neck area.
Cardiovascular Issues
People with untreated hypothyroidism face higher risks of heart disease and heart failure. An underactive thyroid often leads to increased levels of LDL (bad) cholesterol in the bloodstream, which can cause these issues.
Nerve Damage
Long-term untreated hypothyroidism can damage peripheral nerves. This damage, called peripheral neuropathy, can cause pain, numbness, and tingling sensations in the arms and legs.
Fertility Problems
Low thyroid hormone levels can disrupt ovulation, making it harder to conceive. Additionally, some conditions that cause hypothyroidism can further impact fertility.
Risks During Pregnancy
Babies born to parents with untreated thyroid disease may have a greater risk of birth defects than those born to healthy individuals.
Infant Development
If hypothyroidism in newborns goes untreated, it can lead to serious physical and mental development problems. However, with early diagnosis and treatment within the first few months, chances for normal development remain excellent.
Myxedema Coma
This rare but life-threatening condition can occur when hypothyroidism remains untreated for extended periods. Triggers include sedative medications, infections, and physical stress.
Symptoms include severe cold intolerance and drowsiness, followed by extreme lethargy and potentially unconsciousness. This condition requires immediate emergency medical treatment.
