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Myxedema coma

Simmons, Susan PhD, RN, ARNP-BC

doi: 10.1097/01.NURSE.0000376307.36712.6a
Department: ACTION STAT

Myxedema coma

Nurse Practitioner

Walk-in Healthcare Olathe, Kan.

Quivira Family Care Overland Park, Kan.

ARLENE GRANGER, 65, arrives by ambulance accompanied by her husband. She's unresponsive to verbal and noxious stimuli. Mr. Granger says that for the past few days his wife complained of weakness, fatigue, and feeling cold. She also complained of constipation and being unable to empty her bladder completely.

Ms. Granger's vital signs are: BP, 152/120; heart rate, 50; respirations, 12; and temperature, 96° F (35.5° C). You note that her face is puffy with periorbital edema and that her tongue seems enlarged. She's not drooling and her gag reflex is intact. You also note diffuse alopecia and bilateral nonpitting pretibial edema, as well as diminished deep tendon reflexes.

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What's the situation?

Mr. Granger said that when he arrived home from work and found his wife unresponsive, he called 911. She'd been diagnosed with pneumonia a week ago and was taking azithromycin. She has a history of hypothyroidism, but Mr. Granger says he suspects that his wife hasn't taken her levothyroxine for a few months.

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What's your assessment?

Based on Ms. Granger's clinical status and history, including her recent infection, you suspect myxedema coma, a rare but life-threatening condition that occurs when thyroid hormone levels drop too low. The mortality from myxedema coma is 15% to 80% depending on access to immediate and appropriate treatment. Patients at highest risk of death are those with advanced age and refractory bradycardia and hypothermia.

Causes include undiagnosed or undertreated hypothyroidism, discontinuation of hypothyroidism therapy, trauma, surgery, infection (especially respiratory or urinary tract infections), heart failure, or stroke.

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What must be done immediately?

Assess and support Ms. Granger's airway, breathing, and circulation. As ordered, administer 100% oxygen via non-rebreather mask, place her on a cardiac monitor, start an I.V. infusion of 5% dextrose in 0.45% sodium chloride solution, and insert a urinary catheter. The 5% dextrose in 0.45% sodium chloride solution will treat hyponatremia and hypoglycemia associated with myxedema coma.

Obtain blood specimens for arterial blood gas (ABG) analysis, complete blood cell count, chemistry profile, and thyroid function tests. Also obtain a urine specimen for urinalysis. Obtain an ECG and a chest X-ray. Blood test results may show infection or anemia, electrolyte imbalances, hypoglycemia, elevated creatinine, and increased creatine kinase. The urinalysis may show signs of a urinary tract infection; ABGs may show acidosis, hypoxemia, and hypercapnia secondary to bradypnea. The ECG may reveal conduction abnormalities and bradycardia.The chest X-ray may show an enlarged heart and pulmonary edema.



An elevated thyroid-stimulating hormone will confirm the myxedema diagnosis, but treatment can't be delayed while awaiting the lab results. Thyroid replacement with levothyroxine (T4) is the top priority. Ms. Granger is admitted to the ICU for treatment and close monitoring—coma puts her at risk for aspiration and I.V. thyroid hormone can cause dysrhythmias and myocardial infarction. Closely monitor Ms. Granger's respiratory status; if she develops respiratory distress, she may need endotracheal intubation and mechanical ventilation. Monitor her vital signs and follow your facility's policy and procedure for treating hypothermia if it occurs.

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What should be done later?

Ms. Granger is monitored in the ICU for 4 days until she's alert and oriented and can take oral fluids without risk of aspiration. She's then transferred to the medical unit with orders for daily levothyroxine and treatment for pneumonia.

Before discharge, teach Ms. Granger and her husband why she must take her thyroid medication as prescribed and teach them the signs and symptoms of hypo- and hyperthyroidism. Give them printed information to reinforce learning and for future reference at home.

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