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Thyroid Emergencies

Prompt recognition of thyroid emergencies is critical to decrease complications and mortality. Management requires both medical and supportive treatment provided in the critical care setting.

Myxedema Coma

Myxedema coma is a severe, life-threatening emergency that can occur in long-standing, untreated hypothyroidism. Diagnosis is based on laboratory results consistent with hypothyroidism and corresponding clinical manifestations. Treatment should be started quickly given the increased risk of mortality.

Signs and Symptoms of Myxedema Coma

Extreme lethargy and decreased mental status
Hypothermia
Hypotension
Hypoventilation
Hypercapnia
Hypoglycemia
Hyponatremia
Myxedema of lower extremities
Bradycardia
Pericardial effusion

Treatment of Myxedema Coma

Thyroid hormone replacement with T4 and/or T3, usually IV
Glucocorticoids, until coexisting adrenal insufficiency is ruled out
IV fluids for electrolyte replacement
Warming blankets

Nursing Considerations

IV hormone replacement should be administered only as a push through a syringe, rather than through infusion tubing due to high concentrations lost from adherence to polypropylene tubing.
Improvements in serum T3 and T4 concentrations may be seen before the normalization of serum TSH concentrations, and serum thyroid function tests should be obtained every one to two days during treatment.
Improvements in clinical cardiovascular, renal, pulmonary, and metabolic parameters may take as long as a week.

Thyroid Storm

Thyroid storm refers to elevated thyroid hormone concentrations; thyroid storm is a rare diagnosis and is usually triggered by events such as trauma, myocardial infarction, surgery or infection. Diagnosis of thyroid storm is made using a combination of biochemical laboratory tests confirming thyrotoxicosis in a patient displaying the severe, life-threatening symptoms of hyperthyroidism.

Symptoms of Thyroid Storm
Clinical manifestations include exaggeration of common hyperthyroid symptoms (anxiety, fatigue, diaphoresis, heat intolerance, tremors, palpitations, tachycardia, weight loss, hyperreflexia, warm and moist skin, menstrual abnormalities). The following may also be present:
     • Fever
     • Tachycardia and congestive heart failure
     • Vomiting
     • Impaired mental status

Treatment of Thyroid Storm

Beta-blocker to control heart rate
Methimazole or propylthiouracil to decrease production of thyroid hormone
Iodine solution to inhibit thyroid hormone release
Glucocorticoids to decrease the conversion of T4 to T3
Supportive measures include:
- IV fluids
- Oxygen
- Cooling
- Treatment of any precipitating causes
Plasmapheresis when traditional therapy is unsuccessful

Nursing Considerations

Thyroid storm can occur in patients with or without preexisting hyperthyroidism.
Patients with known severe hyperthyroidism who are noncompliant with prescribed antithyroid medications may develop thyroid storm.

References:

Leung, A. M. (September/October 2016). Thyroid emergencies. Journal of Infusion Nursing, 281-286.

Mccaron, K. C. (2009). Deciphering diagnostics: deciphering thyroid function testing. Nursing Made Incredibly Easy, 11-14.

Ross, D. (2017). Myxedema coma. UpToDate. Retrieved from https://www.uptodate.com/contents/myxedema-coma

Ross, D. (2018). Thyroid storm. UpToDate. Retrieved from https://www.uptodate.com/contents/thyroid-storm

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Thyroid Emergencies