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Myxedema Coma Management

Myxedema Coma Management: Suspected Myxedema Coma (adult) → Recognise Clinical Features → Diagnostic Score (optional; never delay treatment) → 1. ICU: T...

Pathway Overview

13 steps

Algorithm Steps

13 total

  1. 01Start

    Suspected Myxedema Coma (adult)

    Reduced consciousness plus hypothermia, bradycardia, hypoventilation, hyponatraemia or a precipitant, in known or likely hypothyroidism. Not all features are needed. Treat on clinical suspicion; do not wait for thyroid results.

  2. 02Action

    Recognise Clinical Features

    Not every feature is present

    • Altered mental status: lethargy, confusion, coma
    • Hypothermia: measure core temperature
    • Bradycardia, hypotension
    • Hypoventilation: hypoxaemia and hypercapnia
    • Hyponatraemia, hypoglycaemia, reduced renal function
    • Non-pitting oedema, delayed reflexes; history of thyroid disease, surgery or radioiodine
  3. 03Action

    Diagnostic Score (optional; never delay treatment)

    Popoveniuc score. High clinical suspicion outweighs a low score.

    • 60 or more: highly suggestive of myxedema coma
    • 25-59: at risk of myxedema coma
    • Below 25: unlikely
    • Components: thermoregulation, CNS, GI, precipitant, cardiovascular, metabolic
  4. 04Action

    1. ICU: Take Bloods, Then Treat at Once

    Do not wait for results before treatment

    • TSH, free T4, free T3. Low or normal TSH with low free T4 suggests a pituitary cause
    • Random cortisol before hydrocortisone, if this does not delay it
    • Electrolytes, creatinine, glucose, FBC, blood gas, blood cultures
    • ECG; echocardiogram if hypotensive (pericardial effusion)
    • ICU: airway, continuous monitoring, core temperature
  5. 05Action

    2. Hydrocortisone Before Thyroid Hormone (adult doses)

    Give first. Do not delay thyroid hormone for cortisol results.

    • Adult: hydrocortisone 100 mg IV now, then 100 mg IV every 8 h
    • Thyroid hormone raises cortisol clearance and can cause adrenal crisis if adrenal or pituitary failure coexists
    • Continue until adrenal insufficiency is excluded, then taper and stop
  6. 06Warning

    Older Age, Coronary Disease or Arrhythmia: Use Lower Thyroid Hormone Doses

    Thyroid hormone can cause tachycardia, arrhythmia and myocardial infarction

    • Use the lower end of the T4 load and of T3 doses in older or small patients and with coronary disease or arrhythmia
    • Avoid high T3 doses: high serum T3 during treatment is linked to death
    • Do not withhold thyroid hormone: untreated myxedema coma is often fatal
  7. 07Action

    3. IV Levothyroxine (adult)

    Give after IV hydrocortisone (adrenal crisis risk). Lower doses in older, small or cardiac patients.

    • Adult: levothyroxine (T4) 200-400 microgram IV loading dose
    • Then 1.6 microgram/kg/day x 0.75 = 1.2 microgram/kg IV once daily (ideal body weight if obese); usually 50-100 microgram daily
    • Optional liothyronine (T3): 5-20 microgram IV load, then 2.5-10 microgram IV every 8 h until clearly recovering
    • Australia: IV T4 and IV T3 are not on the ARTG. Ask pharmacy for Special Access Scheme supply at once
    • If IV supply is delayed: T4 by NG tube, and oral liothyronine (Tertroxin 20 microgram tablets) by NG if needed; dose with endocrinology advice (absorption uncertain; aspiration risk)
  8. 08Action

    4. Supportive Care in ICU

    Ventilate early if needed. Avoid hypotonic fluid and sedatives. Raise sodium slowly.

    • Hypoventilation: intubation and ventilation; recovery can take days to weeks
    • Hypotension: cautious isotonic fluid; vasopressors if needed until hormones act
    • Hyponatraemia with severe symptoms: 3% saline 150 mL IV over 20 min, repeat per protocol
    • Raise sodium by no more than 10 mmol/L in the first 24 h and 8 mmol/L per 24 h after; hormones can raise it fast
    • Hypothermia: passive rewarming; active external warming can cause hypotension
    • Hypoglycaemia: IV glucose; use glucose-containing isotonic fluid
    • Mild hyponatraemia without hypotension: restrict free water
    • Avoid sedatives and opioids; if essential, give the lowest dose
  9. 09Action

    5. Find and Treat the Precipitant

    Infection is the most common trigger

    • Sepsis possible: blood cultures, then empirical broad-spectrum antibiotics
    • Drugs: sedatives, opioids, antipsychotics, antidepressants, anaesthetics, amiodarone, lithium
    • Stopped thyroid hormone; cold exposure
    • Stroke, myocardial infarction, heart failure, GI bleeding, trauma, surgery
  10. 10Action

    6. Monitor in ICU

    Clinical response is the main target

    • Mental status, core temperature, ventilation, BP, continuous ECG
    • Sodium every 4-6 h while low; glucose often
    • Free T4 and T3 every 1-2 days; TSH falls more slowly
    • High T3: reduce thyroid hormone dose
  11. 11Decision

    Improving? (mental status, temperature, BP, breathing)

    Organ function often improves within a week; check hormone levels at 1-2 days

  12. If Yes
    1. 12Outcome

      Improving: Continue, Then Change to Oral T4

      Continue IV therapy until the patient can take oral or enteral T4. Oral T4 dose is higher: IV dose divided by 0.75.

      • Change to oral T4 when awake and swallowing, or give by NG tube
      • Oral or NG T4: about 1.6 microgram/kg/day, ideal body weight if obese (for example 75 microgram IV = 100 microgram oral); lower in older or cardiac patients
      • Stop T3 when clearly recovering
      • Taper and stop hydrocortisone once adrenal insufficiency is excluded
      • Find the cause of hypothyroidism; arrange endocrinology follow-up
    If No
    1. 13Outcome

      Not Improving: Reassess and Escalate

      Seek endocrinology and ICU consultant advice. Recheck precipitant and thyroid levels.

      • Look again for sepsis, bleeding, myocardial infarction, pericardial effusion, adrenal crisis
      • Free T4 or T3 not rising, or TSH not falling: increase T4 and/or add T3, with cardiac caution
      • High T3: reduce the dose

Guideline Source

American Thyroid Association Guidelines for the Treatment of Hypothyroidism (Jonklaas et al., Thyroid 2014), Myxedema coma recommendations 21a-21d

DOI: 10.1089/thy.2014.0028View Guideline

Clinical Safety Information

Clinical Decision Support — Not a Substitute for Clinical Judgment

Individual patient factors may require deviation from these recommendations.

Known Limitations

  • Adults only: doses are not for children
  • Evidence is expert opinion and case series; no randomised trials
  • IV levothyroxine and IV liothyronine are not on the Australian ARTG; supply is via the Special Access Scheme
  • Reported mortality is 25-60% even with prompt treatment

Contraindicated Populations

pediatric

Applicable Regions

AUUSEU

AU: IV levothyroxine and IV liothyronine are not on the ARTG; hospital pharmacy obtains them via the Special Access Scheme. Oral liothyronine (Tertroxin 20 microgram tablets) is registered.

EU: Similar management approach

US: IV levothyroxine preparation availability varies

Version 2Next review: 2027-09-30

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Frequently Asked Questions

What is the Myxedema Coma Management?

The Myxedema Coma Management is a emergency clinical algorithm for Endocrinology. It provides a structured decision tree to guide clinical decision-making, based on American Thyroid Association Guidelines for the Treatment of Hypothyroidism (Jonklaas et al., Thyroid 2014), Myxedema coma recommendations 21a-21d.

What guideline is the Myxedema Coma Management based on?

This algorithm is based on American Thyroid Association Guidelines for the Treatment of Hypothyroidism (Jonklaas et al., Thyroid 2014), Myxedema coma recommendations 21a-21d (DOI: 10.1089/thy.2014.0028).

What are the limitations of the Myxedema Coma Management?

Known limitations include: Adults only: doses are not for children; Evidence is expert opinion and case series; no randomised trials; IV levothyroxine and IV liothyronine are not on the Australian ARTG; supply is via the Special Access Scheme; Reported mortality is 25-60% even with prompt treatment. Individual patient factors may require deviation from these recommendations.

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