eMedicine Specialties > Endocrinology > Thyroid

Myxedema Coma or Crisis: Follow-up

Author: Elena Citkowitz, MD, PhD, FACP, Clinical Professor of Medicine, Yale University School of Medicine; Director, Cholesterol Management Center, Director, Cardiac Rehabilitation, Department of Medicine, Hospital of St Raphael
Contributor Information and Disclosures

Updated: Aug 5, 2008

Follow-up

Further Inpatient Care

• Closely monitor vital signs, electrolytes, and glucose until the levels are within reference ranges and the patient is alert.
• Substitute oral medications for intravenous ones in patients who are extubated and eating.
• Watch for signs of infection, myocardial ischemia, and congestive heart failure.
• Patients who, before hospitalization, did not take their thyroid medication regularly must be evaluated to determine whether they require assistance in taking their thyroid hormone replacement every day.
• Institute physical therapy to assist in strength training and reconditioning.

Further Outpatient Care

• Follow-up care is necessary to ensure compliance with thyroid hormone replacement.
• If primary hypothyroidism was diagnosed, assess the TSH level every 6 weeks and adjust the T4 dose. Once a normal TSH level is obtained, it may be monitored yearly. If compliance is an issue, check the patient every 3-6 months.
• In hypothyroidism secondary to pituitary dysfunction, monitor free T4 levels. The TSH level is not an accurate measure of thyroid function.
• Obtain assurance that the precipitants of the initial presentation will not recur.

Inpatient & Outpatient Medications

• Oral levothyroxine is taken daily at least 1 hour before meals.
• If adrenal insufficiency or pituitary dysfunction has been diagnosed, replacement hormones must be taken as appropriate.

Transfer

• Patients who are awake, no longer dependent on a ventilator, and medically stable may be transferred from the intensive care unit to a medical floor. Before the patient is discharged to return home, transfer to a skilled-care nursing facility for further care and rehabilitation may be necessary.

Deterrence/Prevention

• Patients with a history of thyroid resection or ablation for hyperthyroidism and persons with a history of Hashimoto thyroiditis are at risk for developing hypothyroidism, and the TSH level should be monitored yearly. Such patients should be informed that hypothyroidism could occur in the future. They should understand the symptoms that signal the condition and the need to seek medical attention for appropriate testing.

• Patients who are likely to be noncompliant with medication regimens must have their thyroid function closely monitored.

• In cold climates, inadequately heated residences are a significant cause of myxedema coma/crises in patients with undiagnosed or inadequately treated hypothyroidism.

Complications

• Adrenal crisis is a major complication if patients presenting with myxedema coma/crisis also have adrenal insufficiency and are not treated concomitantly with stress doses of intravenous corticosteroids.
• Myocardial infarction can cause myxedema coma/crisis but may also be a complication of intravenous treatment with thyroid replacement hormones in patients whose myocardial function is already precarious.

Prognosis

Observational studies have analyzed the predictors of survival for patients presenting with myxedema coma.

• In a study of 11 patients with myxedema coma in which 7 survived, statistically significant factors correlated with survival included the following⁶ :
  • Coma on entry
  • Lower Glasgow Coma Scale
  • High APACHE II score 
•  The following factors were not significantly correlated with survival:
  • Age
  • Body temperature
  • Heart rate
  • Free T4, TSH
• In a study of 23 consecutive patients presenting with myxedema coma, 11 of whom survived, statistically significant predictors of mortality included the following¹³ :
  • Hypotension and bradycardia at presentation
  • Need for mechanical ventilation
  • Hypothermia that is not responsive to treatment
  • Sepsis
  • Intake of sedatives
  • Lower Glasgow Coma Scale
  • High APACHE II score
  • High Sequential Organ Failure Assessment (SOFA) score.  The SOFA score at baseline was most predictive, and a day 3 score of more than 6 was highly predictive of a poor outcome.

Patient Education

• Patients must be counseled regarding the necessity of taking daily thyroid hormone replacement and of being monitored on a regular basis so that their TSH level remains within the normal range.  
• Patients with a history of Hashimoto thyroiditis or who have undergone thyroid irradiation or resection should be counseled that hypothyroidism might occur in the future. They should be familiarized with the symptoms that suggest the presence of hypothyroidism and should understand the necessity of seeking prompt medical attention for appropriate testing.
• For excellent patient education resources, visit eMedicine's Endocrine System Center. Also, see eMedicine's patient education articles Thyroid Problems and Myxedema Coma.

Miscellaneous

Medicolegal Pitfalls

• Before presentation, many patients may have been treated with diuretics for edematous states, which may mask the manifestations of myxedema and cause a delay in diagnosis.¹³
• Missing the diagnosis of myxedema coma/crisis is a major cause of increased mortality.¹⁴ In patients presenting with lethargy, bradycardia, hypothermia, and respiratory depression, myxedema coma/crisis should be considered. Tests for thyroid and adrenal function must be drawn immediately, and treatment should be initiated with levothyroxine and hydrocortisone before test results are available.
• Even if myxedema coma/crisis is treated appropriately with thyroid replacement, failure to include stress doses of intravenous steroids can cause adrenal crisis in patients who have adrenal insufficiency on presentation.
• Signs of infection may be subtle in patients with myxedema coma/crisis. Patients are hypothermic, and leukocytosis is not common. A WBC differential may be one of the few clues to the presence of infection or sepsis. Pan-cultures should be obtained as part of the initial workup.
• In patients who have coronary artery disease, myocardial ischemia/infarction may be either a precipitant of myxedema coma/crisis or a consequence of rapid thyroid hormone replacement. Cardiac enzyme assays are a necessary part of the initial workup and management of these patients. Older patients should receive lower doses of thyroid hormone and should be closely monitored for signs of ischemia.

• Late intubation is a risk for increased mortality from myxedema coma. Respiratory support should be instituted if hypercapnia is detected.

• Administration of all medications must be adjusted for the reduction in drug metabolism and clearance that occurs with myxedema coma/crisis. Extremely careful oversight is necessary in order to avoid overmedication, especially of anesthetics and of drugs with a narrow therapeutic margin.

• For patients who have already been anticoagulated with warfarin, correction of hypothyroidism may necessitate a decrease in the dose of warfarin needed to maintain a therapeutic level of anticoagulation. The international normalized ratio (INR) should be closely monitored during thyroid hormone repletion.

Special Concerns

• Geriatric patients and patients with risk factors for coronary artery disease should be carefully monitored to ensure that an acute ischemic event is neither a precipitant of myxedema coma/crisis nor a consequence of treatment.

• Search for CME/CE on This Topic »

• Thyroid Problems Overview
• Thyroid Problems Treatment
• Thyroid Problems Causes
• Thyroid Problems Symptoms
• Endocrine System Center
• Myxedema Coma Overview