• Clinical features of myxedema coma
  •  Classic combination of AMS and hypothermia but may also manifest with:
    • hypotension, bradycardia
    • hyponatremia, hypoglycemia
    • hypoventilation/hypercapnia
    • Non-pitting edema of the hands/feet/face and enlarged tongue (abnormal deposits of mucin)
  • Often precipitated by infection, cessation of thyroid replacement, ACS
  
  
  
  

  Posted 07/14/16 02:24:29 PM by Matthew Cummings

• Diagnostic pearls
  • Extensive scoring system exists surrounding above criteria but derived from small sample size (21 patients), thus...
  • MUST consider in any altered patient w/ hypothermia, hyponatremia, and/or hypercapnia and send TSH, FT4, and cortisol (assessing for concomitant adrenal insufficiency)
  
  
  
  

  Posted 07/14/16 02:32:22 PM by Matthew Cummings

• Supportive care for myxedema coma
  • Supportive care is CRUCIAL
    • Hypercapnia --> NPPV (depending on mental status), mechanical ventilation
    • Hypotension --> volume resuscitation
    • Hypothermia --> rewarming in monitored setting (at risk for hyperkalemia, arrhythmias)
    • Hyponatremia --> frequent BMPs, appropriate correction
    • Precipitant --> pan-culture/abx, EKG/troponin/TTE, etc
  • Glucocorticoid administration: treat empirically w/ "stress" dose hydrocortisone (100mg q8h) until can rule out adrenal insufficiency
    • Therefore important to send cortisol early prior to treatment if possible
  
  

  Posted 07/14/16 02:37:05 PM by Matthew Cummings

• Thyroid replacement strategies --> controversial issue (limited prospective clinical data)
  • Debate as to benefit of administering BOTH T3/T4 or just T4
  • Always prefer IV therapy (poor GI absorption in myxedema) 
    • T4 (levothyroxine): loading doses usually begin ~200mcg and then daily dose of ~1.5mcg/kg/day
    • T3 (liothyronine): loading doses begin ~5mcg, and then daily doses starting at 2.5mcg q8h
    • Prefer lower doses in elderly, underweight patients and those w/ arrhythmia, ACS, CHF) 
  
  

  Posted 07/14/16 02:46:19 PM by Matthew Cummings

• For further reading...

  Myxedema coma: clinical review
  Thyroid replacement in myxedema coma
  
  

  Posted 07/14/16 06:16:47 PM by Matthew Cummings

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