Hypothyroidism (Myxedema)

  1. General information
    1. Slowing of metabolic processes caused by hypofunction of the thyroid gland with decreased thyroid hormone secretion; causes myxedema in adults and cretinism in children (see Congenital Hypothyroidism, in Unit 5).
    2. Occurs more often in women between ages 30-60
    3. Primary hypothyroidism: atrophy of the gland possibly caused by an autoimmune process
    4. Secondary hypothyroidism: caused by decreased stimulation from pituitary TSH
    5. Iatrogenic: surgical removal of the gland or overtreatment of hyperthyroidism with drugs or radioactive iodine
    6. In severe or untreated cases, myxedema coma may occur
      1. Characterized by intensification of signs and symptoms of hypothyroidism and neurologic impairment leading to coma
      2. Mortality rate high; prompt recognition and treatment essential
      3. Precipitating factors: failure to take prescribed medications; infection; trauma, exposure to cold; use of sedatives, narcotics, or anesthetics
  2. Medical management
    1. Drug therapy: levothyroxine (Synthroid), thyroglobulin (Proloid), dessicated thyroid, liothyronine (Cytomel)
    2. Myxedema coma is a medical emergency.
      1. IV thyroid hormones
      2. Correction of hypothermia
      3. Maintenance of vital functions
      4. Treatment of precipitating causes
  3. Assessment findings
    1. Fatigue; lethargy; slowed mental processes; dull look; slow, clumsy movements
    2. Anorexia, weight gain, constipation
    3. Intolerance to cold; dry, scaly skin; dry, sparse hair; brittle nails
    4. Menstrual irregularities; generalized interstitial nonpitting edema
    5. Bradycardia, cardiac complications (CAD, angina pectoris, MI, CHF)
    6. Increased sensitivity to sedatives, narcotics, and anesthetics
    7. Exaggeration of these findings in myxedema coma: weakness, lethargy, syncope, bradycardia, hypotension, hypoventilation, subnormal body temperature
    8. Diagnostic tests
      1. Serum T3 and T4 level low
      2. Serum cholesterol level elevated
      3. RAIU decreased
  4. Nursing interventions
    1. Monitor vital signs, I&O, daily weights; observe for edema and signs of cardiovascular complications.
    2. Administer thyroid hormone replacement therapy as ordered and monitor effects.
      1. Observe for signs of thyrotoxicosis (tachycardia, palpitations, nausea, vomiting, diarrhea, sweating, tremors, agitation, dyspnea).
      2. Increase dosage gradually, especially in clients with cardiac complications.
    3. Provide a comfortable, warm environment.
    4. Provide a low-calorie diet.
    5. Avoid the use of sedatives; reduce the dose of any sedative, narcotic, or anesthetic agent by half as ordered.
    6. Institute measures to prevent skin breakdown.
    7. Provide increased fluids and foods high in fiber to prevent constipation; administer stool softeners as ordered.
    8. Observe for signs of myxedema coma; provide appropriate nursing care.
      1. Administer medications as ordered.
      2. Maintain vital functions: correct hypothermia, maintain adequate ventilation.
    9. Provide client teaching and discharge planning concerning
      1. Thyroid hormone replacement
        1. take daily dose in the morning to prevent insomnia.
        2. self-monitor for signs of thyrotoxicosis.
      2. Importance of regular follow-up care
      3. Need for additional protection in cold weather
      4. Measures to prevent constipation