What are the symptoms and treatment options for myxedema?

Symptoms and Treatment of Myxedema

Myxedema is characterized by severe hypothyroidism with distinctive symptoms including fatigue, cold intolerance, mental slowness, dry skin, facial puffiness, and hoarse voice, which can progress to life-threatening myxedema coma if left untreated. 1

Clinical Presentation of Myxedema

Common Symptoms

• Fatigue and weakness
• Cold intolerance
• Mental and physical slowness
• Dry skin and hair loss
• Characteristic facial puffiness (myxedematous facies)
• Hoarse voice
• Weight gain
• Constipation
• Muscle cramps
• Intellectual slowness and memory impairment
• Insomnia 2, 1, 3

Advanced Signs

• Bradycardia
• Hypothermia
• Non-pitting edema (especially periorbital)
• Delayed relaxation of deep tendon reflexes
• Macroglossia (enlarged tongue)
• Altered mental status 4, 1

Myxedema Coma - Medical Emergency

Myxedema coma represents the extreme manifestation of hypothyroidism and is characterized by:

• Altered mental status/coma
• Hypothermia
• Bradycardia
• Hypoventilation
• Hypotension
• Hyponatremia
• Hypoglycemia 4, 5

Precipitating factors for myxedema coma include:

• Infection (most common)
• Cold exposure
• Trauma
• Medications (sedatives, narcotics)
• Stroke
• Heart failure 5

Diagnostic Approach

Diagnosis is based on:

1. Clinical presentation
2. Laboratory confirmation:
   • Elevated TSH level
   • Low free T4 level 1, 3

Treatment Protocol

For Myxedema Without Coma

1. Levothyroxine (T4) replacement therapy:

   • Starting dose: 1.5-1.8 mcg/kg/day orally
   • For elderly patients (>60 years) or those with cardiac disease: Start with lower dose (12.5-50 mcg/day) 3
   • Titrate dose gradually every 4-6 weeks based on TSH levels 4

2. Monitoring:

   • Check TSH and free T4 every 4-6 weeks during dose adjustment
   • Once stable, monitor every 6-12 months 4
   • Target: Normalization of TSH within reference range 4

For Myxedema Coma (Medical Emergency)

1. Immediate hospitalization in intensive care unit 4, 5

2. Thyroid hormone replacement:

   • First-line: IV levothyroxine - loading dose of 200-400 mcg on day 1 4
   • If IV levothyroxine unavailable: Oral levothyroxine 300-500 μg loading dose, followed by tapering over 3-5 days 6
   • Alternative: Liothyronine (T3) via nasogastric tube 1

3. Supportive care:

   • Hydrocortisone 100 mg IV every 8 hours (to cover potential adrenal insufficiency) 4, 5
   • Careful fluid management (monitor for hyponatremia)
   • Passive rewarming for hypothermia
   • Ventilatory support if needed
   • Treatment of precipitating factors (especially infection) 5

Special Considerations

• Elderly patients: Start with lower doses and titrate more slowly to avoid cardiac complications 7
• Cardiac disease: Use caution as overtreatment may precipitate angina or arrhythmias 7
• Diabetes: Thyroid hormone replacement may worsen glycemic control; monitor blood glucose and adjust antidiabetic medications 8, 7
• Adrenal insufficiency: Must treat with glucocorticoids before starting thyroid hormone replacement 8, 7
• Anticoagulants: Monitor prothrombin time closely as thyroid status affects anticoagulant sensitivity 8

Pitfalls to Avoid

1. Delayed diagnosis: Consider hypothyroidism in patients with unexplained hyponatremia 5
2. Overly aggressive treatment in elderly or cardiac patients
3. Failure to identify and treat precipitating factors in myxedema coma
4. Missing concomitant adrenal insufficiency
5. Inadequate monitoring during treatment

Early recognition and appropriate treatment of myxedema, particularly myxedema coma, is essential to reduce mortality and improve outcomes.