ُmyoexedema

myxedema coma

Myxedema coma is a life-threatening disorder that progresses
from hypothyroidism.
causes Causes of hypothyroidism include:
• pituitary failure to produce TSH
• hypothalamic failure
• chronic autoimmune thyroiditis (Hashimoto’s disease)
• amyloidosis and sarcoidosis
• inability to synthesize hormones
• pituitary failure to produce TSH
• postthyroidectomy effects
• postradiation therapy effects.
Myxedema coma is a life-threatening form of hypothyroidism.

There are two classifications of hypothyroidism: primary and secondary. Primary hypothyroidism originates as a disorder of the thyroid gland. Secondary hypothyroidism is caused by a failure to stimulate normal thyroid function or an inability to synthesize thyroid hormones due to an iodine deficiency (usually dietary) or use of antithyroid medications.
causes
Myxedema coma can result from either primary or secondary hypothyroidism or progresses slowly and gradually. It’s usually precipitated by infection, exposure to cold, or sedative use. Cellular metabolism decreases to a fatal level if the patient with myxedema coma is left untreated.
The progression to myxedema coma is usually gradual but may develop abruptly if stress aggravates severe or prolonged hypothyroidism.
Inspect and assess

Periorbital edema; dry, flaky skin; thick, brittle nails; and sacral or peripheral edema may be present in the patient with myxedema coma. Cardiac assessment may reveal muffled or S3 heart sounds.
In addition, look for changes in the patient’s overall appearance and behavior, including:
• decreased mental ability (slight mental slowing to severe obtundation) • thick and dry tongue,• hoarseness
• slow and slurred speech.Assessment findings also include:
• progressive stupor, • significantly depressed respirations and adventitious breath sounds
• hypoglycemia
• hyponatremia
• hypotension and bradycardia
• severe hypothermia without shivering
• decreased deep tendon reflexes
• alopecia
• rough, dry skin.
Lab. Finding
Several test findings are useful in diagnosing myxedema coma:
• Serum levels of T3 and T4 are decreased.
• Serum levels of TSH are increased.
• Radioactive iodine (131I) testing reveals low serum levels of thyroid hormones.
• Radioisotope scanning of thyroid tissue is used to identify ectopic thyroid tissue.
• A CT scan, MRI, or skull X-ray may disclose an underlying cause, such as pituitary or hypothalamic lesions.
• Chest X-ray may show pleural effusion.
Treatment
Rapid treatment may be necessary for patients in myxedema coma, including:
• administration of I.V. hydrocortisone and I.V. levothyroxine (a thyroid agent)
• possible ventilatory support if the patient is comatose, • I.V. fluid replacement• warming devices
• maintenance thyroid replacement.
Nursing Management
• Assess the patient’s LOC and ability to maintain a patent airway.
• Monitor the patient’s respiratory status, adequacy of ventilation and oxygen saturation, and ABG levels Administer
supplemental oxygen as ordered and anticipate the need for intubation and mechanical ventilation.
• Monitor vital signs and cardiac arrhythmias. Auscultate for muffled heart sounds or changes such as S3.
• Monitor temperature closely until the patient is stable, and institute warming measures such as applying a warming blanket.
• Administer medications as ordered. Withhold sedatives or give
them in reduced dosages.• Administer I.V. fluids as ordered and monitor fluid balance status,
serum electrolytes, and blood glucose levels.• Assess for possible sources of infection—such as blood, sputum, and urine—and provide meticulous skin care.