Contents
1. Etiology (Causes)
Myxedema is a severe form of hypothyroidism where extreme thyroid hormone deficiency causes:
- Primary Causes:
- Autoimmune thyroiditis (Hashimoto’s disease)
- Thyroidectomy (surgical removal)
- Radioactive iodine treatment
- Severe iodine deficiency
- Secondary Causes:
- Pituitary/hypothalamic dysfunction
- Certain medications (lithium, amiodarone)
2. Symptoms
Classic Physical Signs:
- Non-pitting edema (swelling that doesn’t indent when pressed)
- Puffy face (“moon face”) and swollen eyelids
- Thickened skin with waxy, dry texture
- Hoarse voice and slowed speech
- Hair loss (especially outer eyebrows)
Systemic Effects:
- Hypothermia (low body temperature)
- Bradycardia (slow heart rate)
- Mental sluggishness (confusion, depression)
- Constipation
- Muscle weakness
3. Diagnosis
Key Tests:
- Thyroid Function Tests:
- Extremely high TSH (often >50 mIU/L)
- Very low free T4
- Antibody Tests (anti-TPO for Hashimoto’s)
- Emergency Tests for Myxedema Coma:
- Low sodium (hyponatremia)
- High CO₂
- Anemia
Imaging:
- Thyroid ultrasound (check for atrophy/nodules)
- Brain MRI (if pituitary cause suspected)
4. Treatment
Immediate (Myxedema Coma):
- IV levothyroxine (T4) + IV liothyronine (T3)
- IV glucocorticoids (hydrocortisone)
- Gradual rewarming (avoid rapid temperature changes)
Long-Term Management:
- Oral levothyroxine (1.6 mcg/kg/day)
- Dose adjustments every 6-8 weeks until TSH normalizes
- For Elderly/Heart Patients: Start with 25-50 mcg/day
5. Prevention
- Regular TSH checks if at risk (family history, autoimmune diseases)
- Proper iodine intake (150 mcg/day) – but avoid excess
- Medication adherence for known hypothyroidism
- Prompt treatment of thyroiditis
6. When to Seek Emergency Care
Go to the ER immediately if a hypothyroid patient develops:
- Body temperature <35°C (95°F)
- Extreme lethargy/confusion
- Difficulty breathing
- Seizures/loss of consciousness
7. How to Avoid Myxedema?
✔ Never stop thyroid meds without doctor supervision
✔ Monitor for symptoms if you’ve had thyroid surgery/radiation
✔ Treat infections promptly (can trigger crisis)
✔ Wear medical alert jewelry if diagnosed with hypothyroidism
Key Takeaways
- Myxedema is life-threatening untreated but preventable
- Skin changes + mental decline are red flags
- Myxedema coma has 30-50% mortality – requires ICU care
- Levothyroxine must be taken lifelong for thyroid failure
Did You Know?
Cold weather can worsen symptoms – patients often feel coldest in winter!
