Thyroid Disorders

The thyroid gland is a vital endocrine organ that sits at the base of your neck, wrapping around the windpipe. Despite weighing only about 20 grams, it has an enormous impact on your health. The thyroid produces hormones - primarily thyroxine (T4) and triiodothyronine (T3) - that regulate metabolism, heart rate, body temperature, and many other functions.

How the Thyroid Works

• Hormone production: TSH from pituitary stimulates thyroid
• T4 and T3: Main thyroid hormones affecting metabolism
• Iodine requirement: Essential for hormone synthesis
• Feedback loop: Body maintains precise hormone levels
• Calcitonin: Also produces hormone for calcium regulation

Prevalence and Impact

• 20 million Americans have thyroid disease
• Up to 60% are unaware of their condition
• Women 5-8 times more likely to have thyroid problems
• 1 in 8 women will develop thyroid disorder in lifetime
• Can occur at any age, including infancy
• Often runs in families

Types of Thyroid Disorders

• Functional disorders:
  • Hypothyroidism (underactive thyroid)
  • Hyperthyroidism (overactive thyroid)
  • Subclinical thyroid disease
• Structural disorders:
  • Goiter (enlarged thyroid)
  • Thyroid nodules
  • Thyroid cancer
  • Thyroiditis (inflammation)
• Autoimmune disorders:
  • Hashimoto's thyroiditis
  • Graves' disease
  • Postpartum thyroiditis

Why Thyroid Health Matters

Thyroid hormones affect virtually every cell in your body. They regulate:

• Metabolic rate and energy production
• Heart rate and blood pressure
• Body temperature
• Digestive function
• Muscle control
• Brain development and function
• Bone maintenance
• Reproductive health

Hypothyroidism occurs when the thyroid doesn't produce enough hormones, slowing down body functions. It's the most common thyroid disorder.

Causes of Hypothyroidism

• Hashimoto's thyroiditis:
  • Most common cause in developed countries
  • Autoimmune attack on thyroid
  • Gradual thyroid failure
• Treatment-related:
  • Radioactive iodine therapy
  • Thyroid surgery
  • Radiation to neck
• Other causes:
  • Iodine deficiency (globally common)
  • Medications (lithium, amiodarone)
  • Congenital hypothyroidism
  • Pituitary disorders

Symptoms of Hypothyroidism

Symptoms develop slowly and may include:

• General: Fatigue, weakness, weight gain
• Cold intolerance: Feeling cold when others don't
• Skin/hair: Dry skin, hair loss, brittle nails
• Mental: Depression, memory problems, brain fog
• Physical: Constipation, muscle aches, joint pain
• Reproductive: Heavy periods, infertility
• Heart: Slow heart rate, high cholesterol
• Voice: Hoarseness, puffy face

Diagnosis

• TSH test: Elevated in primary hypothyroidism
• Free T4: Low levels confirm diagnosis
• Antibodies: TPO antibodies for Hashimoto's
• Reference ranges: May vary by lab and age

Treatment

• Levothyroxine:
  • Synthetic T4 hormone
  • Daily oral medication
  • Requires empty stomach
  • Lifelong treatment usually needed
• Monitoring:
  • Regular TSH checks
  • Dose adjustments as needed
  • Annual follow-up when stable

Hyperthyroidism occurs when the thyroid produces too much hormone, speeding up body functions. It's less common than hypothyroidism but can be more immediately serious.

Causes of Hyperthyroidism

• Graves' disease:
  • Most common cause (70-80%)
  • Autoimmune stimulation of thyroid
  • May cause eye problems
• Toxic nodules:
  • Single or multiple overactive nodules
  • More common in older adults
• Thyroiditis:
  • Temporary hyperthyroidism
  • Inflammation releases stored hormone
• Other causes:
  • Excessive iodine intake
  • Thyroid medication overdose
  • Pituitary adenoma (rare)

Symptoms of Hyperthyroidism

• Metabolic: Weight loss despite good appetite
• Heart: Rapid heartbeat, palpitations, irregular rhythm
• Nervous system: Anxiety, irritability, tremors
• Heat intolerance: Excessive sweating, warm skin
• Digestive: Frequent bowel movements, diarrhea
• Muscles: Weakness, especially in thighs
• Eyes: Bulging, irritation (Graves' disease)
• Skin: Thinning, fine hair
• Sleep: Insomnia, restlessness

Diagnosis

• TSH: Suppressed (very low)
• Free T4 and T3: Elevated
• Antibodies: TSI or TSHR for Graves'
• Radioactive iodine uptake: Determines cause
• Thyroid scan: Shows hot or cold nodules

Treatment Options

• Antithyroid medications:
  • Methimazole (preferred)
  • Propylthiouracil (PTU)
  • Block hormone production
• Radioactive iodine:
  • Destroys overactive thyroid tissue
  • Often leads to hypothyroidism
  • Not for pregnant women
• Surgery:
  • Thyroidectomy
  • For large goiters or cancer concern
  • Requires lifelong hormone replacement
• Beta blockers:
  • Control symptoms quickly
  • Reduce heart rate and tremors
  • Not a cure

Thyroid nodules are lumps in the thyroid gland. They're very common, especially in women and older adults. Most are benign (non-cancerous).

Facts About Nodules

• Present in up to 50% of adults by age 60
• Only 5-10% are cancerous
• Often discovered incidentally
• May be single or multiple
• Can be solid or fluid-filled (cysts)

Types of Nodules

• Colloid nodules: Benign overgrowths
• Follicular adenomas: Benign tumors
• Thyroid cysts: Fluid-filled, usually benign
• Inflammatory nodules: From thyroiditis
• Thyroid cancer: Various types
• Multinodular goiter: Multiple nodules

Evaluation Process

• Physical exam: Size, consistency, mobility
• Thyroid function tests: Usually normal
• Ultrasound: Determines size and characteristics
• Fine needle aspiration (FNA):
  • Biopsy for suspicious nodules
  • Usually for nodules >1 cm
  • Guided by ultrasound
• Molecular testing: For indeterminate biopsies

Management

• Benign nodules: Monitor with ultrasound
• Suspicious/malignant: Surgery usually needed
• Hyperfunctioning: May need treatment
• Large nodules: Surgery if compressive symptoms

A goiter is an enlargement of the thyroid gland. It can occur with normal, low, or high thyroid function.

Causes

• Iodine deficiency: Most common worldwide
• Hashimoto's thyroiditis: Autoimmune inflammation
• Graves' disease: Diffuse enlargement
• Multinodular goiter: Multiple nodules
• Thyroid cancer: Less common
• Pregnancy: Temporary enlargement
• Medications: Lithium, others

Symptoms

• Visible neck swelling
• Tight feeling in throat
• Difficulty swallowing
• Difficulty breathing when severe
• Coughing
• Voice changes
• May have no symptoms if small

Treatment

• Observation: Small, asymptomatic goiters
• Thyroid hormone: May shrink some goiters
• Radioactive iodine: For toxic goiters
• Surgery: Large or compressive goiters
• Iodine supplementation: If deficient

Thyroid cancer is relatively uncommon but generally has an excellent prognosis when detected early. Incidence has increased, partly due to improved detection.

Types of Thyroid Cancer

• Papillary (80%):
  • Most common and least aggressive
  • Excellent prognosis
  • Spreads to lymph nodes
• Follicular (10-15%):
  • Good prognosis
  • May spread to distant organs
• Medullary (3-4%):
  • From C cells
  • May be hereditary
  • Produces calcitonin
• Anaplastic (1-2%):
  • Very aggressive
  • Poor prognosis
  • Occurs in older adults
• Lymphoma: Rare, usually treatable

Risk Factors

• Radiation exposure to neck
• Family history
• Female gender
• Age (can occur at any age)
• Hereditary syndromes
• Large benign nodules

Treatment

• Surgery: Primary treatment
• Radioactive iodine: After surgery for some types
• Thyroid hormone: Suppression therapy
• External radiation: For advanced cases
• Chemotherapy: Rarely needed
• Targeted therapy: For advanced cancer

Thyroiditis is inflammation of the thyroid gland that can cause temporary hyperthyroidism followed by hypothyroidism.

Types of Thyroiditis

• Hashimoto's thyroiditis:
  • Most common form
  • Autoimmune
  • Leads to permanent hypothyroidism
• Subacute thyroiditis:
  • Painful thyroid
  • Often follows viral infection
  • Self-limited
• Postpartum thyroiditis:
  • Occurs within year after delivery
  • Affects 5-10% of women
  • Usually temporary
• Silent thyroiditis:
  • Painless
  • Similar to postpartum type
  • Often resolves
• Drug-induced:
  • From medications like amiodarone
  • Interferon
  • Lithium

General Pattern

• Phase 1: Hyperthyroid (weeks to months)
• Phase 2: Hypothyroid (weeks to months)
• Phase 3: Recovery (usually)
• Some develop permanent hypothyroidism

Blood Tests

• TSH (Thyroid Stimulating Hormone):
  • Most sensitive test
  • High in hypothyroidism
  • Low in hyperthyroidism
  • Normal range: 0.4-4.0 mIU/L (varies)
• Free T4:
  • Active thyroid hormone
  • Confirms diagnosis
  • Not affected by protein levels
• Free T3:
  • Active form
  • Useful in hyperthyroidism
  • May be normal in early hypothyroidism
• Thyroid antibodies:
  • TPO antibodies (Hashimoto's)
  • TSI or TSHR antibodies (Graves')
  • Thyroglobulin antibodies

Imaging Studies

• Ultrasound:
  • First-line imaging
  • Evaluates nodules
  • Guides biopsies
  • No radiation
• Radioactive iodine scan:
  • Shows function
  • Hot vs cold nodules
  • Determines cause of hyperthyroidism
• CT or MRI:
  • For large goiters
  • Evaluate extension
  • Cancer staging

Other Tests

• Fine needle aspiration: Biopsy of nodules
• Thyroid uptake: Measures iodine uptake
• Calcitonin: Screen for medullary cancer
• Genetic testing: For familial cancers

General Principles

• Treatment depends on specific disorder
• Goal is to restore normal thyroid function
• Regular monitoring essential
• Most conditions very treatable
• Individualized approach needed

Medication Tips

• Thyroid hormone replacement:
  • Take on empty stomach
  • Same time daily
  • Avoid calcium, iron within 4 hours
  • Be consistent with brand
• Antithyroid drugs:
  • Take as directed
  • Watch for side effects
  • Regular blood monitoring

Monitoring

• TSH checks every 6-8 weeks initially
• Annual monitoring when stable
• More frequent during pregnancy
• Adjust for symptoms, not just labs
• Consider age-specific ranges

Special Situations

• Pregnancy:
  • Increased hormone needs
  • Frequent monitoring
  • Critical for baby's development
• Elderly:
  • Start low, go slow
  • Watch cardiac effects
  • Different TSH goals
• Children:
  • Critical for growth/development
  • More frequent monitoring
  • Dose based on weight

Daily Management

• Take medications consistently
• Don't skip doses
• Keep regular doctor appointments
• Get blood tests as recommended
• Report new symptoms promptly
• Maintain medication list

Lifestyle Considerations

• Diet:
  • Adequate iodine (not excessive)
  • Limit goitrogens if hypothyroid
  • Avoid soy with medication
  • Balanced nutrition
• Exercise:
  • Regular activity helps symptoms
  • Start slowly if untreated
  • Adjust as treatment progresses
• Stress management:
  • Stress affects thyroid function
  • Practice relaxation techniques
  • Get adequate sleep

Symptom Tracking

• Keep symptom diary
• Note medication timing
• Track energy levels
• Monitor weight changes
• Record menstrual changes
• Share with doctor

Common Concerns

• Weight management:
  • Thyroid affects metabolism
  • Treatment helps normalize weight
  • Patience during adjustment
• Hair loss:
  • Common with thyroid disorders
  • Usually improves with treatment
  • May take months
• Mood changes:
  • Thyroid affects mood
  • Treatment helps
  • May need additional support

Long-term Outlook

Most thyroid disorders are very manageable with proper treatment. Key points:

• Treatment is usually lifelong but effective
• Regular monitoring prevents complications
• Quality of life can be normal
• Pregnancy possible with good control
• Life expectancy usually normal
• Stay informed about your condition