Myxedema coma: Difference between revisions

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==Background==
==Background==
#Hypothyroidism + mental status changes/coma + hypothermia + precipitating stressor
*Hypothyroidism + mental status changes/coma + hypothermia + precipitating stressor<ref>Wall CR. Myxedema coma: diagnosis and treatment. Am Fam Physician. Dec 1 2000;62(11):2485-90.</ref>
##80% mortality
*Majority of the patients will be > 60yo<ref>Davis PJ, Davis FB. Hypothyroidism in the elderly. Compr Ther. 1984;10:17–23.</ref>
#Occurs in 0.1% of patients with hypothyroidism
*Occurs in 0.1% of patients with hypothyroidism
*Mortality may be as high as 60%<ref>Arlot S et al. Myxoedema coma: response of thyroid hormones with oral and intravenous high-dose L-thyroxine treatment. Intensive Care Med. 1991;17:16–8.</ref>
*Coma does not need to be present but there will be a decline in the patient's mental status.  Sever hypothyroidism may present with severe decompensated hypothyroidism as the first presentation of undiagnosed hypothyroidism<ref>Nicoloff JT et al.  A form of decompensated hypothyroidism. Endocrinol Metab Clin North Am. 1993;22:279–90.</ref>
*The classic myxedematous face, which is characterized by generalized puffiness, macroglossia, ptosis, periorbital edema may not be present, but other signs such as a palpaple goiter and thyroid medication use will help in suspecting the diagnosis.


===Precipitants===
===Precipitants===
#Infection
#[[Sepsis]]
##Bradycardia and hypothermia may mask usual signs of fever
#Bradycardia and hypothermia
#Cold exposure
#Cold exposure
#Trauma
#Trauma
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#Metabolic conditions ([[hypoxia]], [[hypercapnia]], [[hyponatremia]], [[hypoglycemia]])
#Metabolic conditions ([[hypoxia]], [[hypercapnia]], [[hyponatremia]], [[hypoglycemia]])
#Burns
#Burns
#Meds: B-blockers, sedatives, narcotics, phenothiazine, amiodarone
#Meds: B-blockers, sedatives, narcotics, phenothiazine, amiodarone<ref>Mazonson PD et al. Myxedema coma during long-term amiodarone therapy. Am J Med. 1984;77:751–4.</ref>
#Medication non-compliance (thyroid meds)
#Medication non-compliance (thyroid meds)


==Diagnosis==
==Diagnosis==
#Hypothermia
===Hypothermia===
##So common in myxedema that a normal temperature should suggest an underlying infection
*Temperature <35.5°C (95.9°F).
##Absence of shivering distinguishes from accidental hypothermia
===Cardiovascular===
#Cardio
*[[Bradycardia]]
##Bradycardia
*[[Hypotension]]
##Hypotension
===Pulmonary===
#Pulm
*Hypoventilation
##Hypoventilation -> respiratory collapse  
**Early respiratory support with intubation is necessary to prevent respiratory collapse  
###CO2 narcosis
*[[Hypercapnia]]
##Pleural effusions
**There is often diaphragmatic dysfunction that causes worsening hypoventilation.  The dysfunction is reversed after thryroid hormone administration<ref>Martinez FJ et al. Hypothyroidism. A reversible cause of diaphragmatic dysfunction. Chest. 1989;96:1059–63.</ref>
##Upper airway obstruction from glottic edema, vocal cord edema, and macroglossia  
*[[Pleural Effusion]]
#Neuro
*Upper airway obstruction from glottic edema, vocal cord edema, and macroglossia can complicate intubation.
##AMS/coma
===Neurologic===
*[[AMS]]/[[Coma]]


==Work-Up==
==Work-Up==
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#CXR  
#CXR  
#EKG  
#EKG  
==Lab Abnormalities==
*Abnormal Thyroid Hormone Levels
**In primary hypothyroidism then TSH will be elevated and T4 and T3 will be low
**If the patient has secondary hypothroidism (Pituitary dysfunction) the TSH can be low or normal and T4 and T3 will be low
*[[Anemia]]
*[[Rhabdomyolysis|Elevated CPK]]
*[[Renal Failure|Elevated creatinine]]
*Elevated transaminases
*[[Hypercapnia]]
*Hyperlipidemia
*[[Hypoglycemia]]
*[[Hyponatremia]]
*[[Hypoxia]]
*Leukopenia
*Respiratory acidosis
   
   
==Differential Diagnosis==
==Differential Diagnosis==
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==Treatment==
==Treatment==
#Supportive care
===Respiratory Support===
##Respiratory distress
*Early mechanical ventilation will prevent resipatory collapse and severe respiratory acidosis.
###Mechanical ventilation if needed
===Fluid Resuscitation===
##Fluid resuscitation
*Patients are often intravsascularly depleted and have an underlying infection mandating agressive fluid resususcitation
###Patients tend to be intravascularly volume down
*In patients who are hyponatremia, be cautious with rapid correction of hyponatremia and choose an appropriate fluid  
###Hypoglycemia and hyponatremia may be seen
*Hypoglycemic patients will require intravenous dextrose added into the fluids
###Consider cautious fluid hydration with D5NS to address these issues
===Hypotension===
###May consider hypertonic saline if Na<120
*[[Vasopressors]] will be ineffective without concomitant thyroid hormone replacement
##Hypotension
===Hormone Replacment===
###Vasopressors (ineffective w/o thyroid hormone replacement)
*'''Hydrocortisone''' 100mg q8hr IV since there is also adrenal insufficiency present
###'''Hydrocortisone 100mg q8hr IV''' (adrenal insufficiency may also be present)
 
####Give first dose before starting thyroid replacement therapy
 
##Hypothermia
*'''Levothyroxine (T4)''' (generally agreed upon first line therapy)
###Treat w/ passive rewarming (active rewarming may cause hypotension)
**Dose: 100 to 500 mcg (4mcg/kg IV) followed by 75 to 100 mcg administered IV daily until the patient takes oral replacement.<ref>Smallridge RC. Metabolic and anatomic thyroid emergencies: a review. Crit Care Med. 1992;20:276–91</ref>
#Thyroid replacement therapy
**Does require extrathyroidal conversion which can be reduced in myxedema but will have a slow steady onset of action and potentially safer in patients with coronary artery disease (CAD).
##Optimal regimen is controversial
 
##Can give T3 or T4 or both
*'''T3'''
##T4
*Dose: 20mcg IV followed by 10mcg q8hr (Start with 10mcg if elderly or has CAD)
###Advantages
*Does not require extrathyroidal conversion and has more rapid onset but may be harmful in patients with severe coronary artery disease.
####Smooth, slow steady onset of action
===Hypothermia===
####May be safer in pts with CAD
*Treat with passive rewarming
###Disadvantages
*Hypothermia will also reverse with thryoid hormone administration
####Requires extrathyroidal conversion of T4 -> T3 to work (may be reduced in myxedema)
###Dose: Start '''4mcg/kg IV followed by 100mcg IV in 24hr'''
##T3
###Advantages
####Does not require extrathyroidal action to work
####Rapid onset of action
###Disadvantages
####Rapid onset of action (may not be desirable in pts w/ CAD)
###Dose: 20mcg IV followed by 10mcg q8hr until pt is conscious
####Start with 10mcg if elderly or has CAD
#Treat precipitating factors


==Disposition==
==Disposition==
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==Source==
==Source==
*Tintinalli's
<references/>
*Rosen's


[[Category:Endo]]
[[Category:Endo]]

Revision as of 21:15, 1 February 2015

Background

  • Hypothyroidism + mental status changes/coma + hypothermia + precipitating stressor[1]
  • Majority of the patients will be > 60yo[2]
  • Occurs in 0.1% of patients with hypothyroidism
  • Mortality may be as high as 60%[3]
  • Coma does not need to be present but there will be a decline in the patient's mental status. Sever hypothyroidism may present with severe decompensated hypothyroidism as the first presentation of undiagnosed hypothyroidism[4]
  • The classic myxedematous face, which is characterized by generalized puffiness, macroglossia, ptosis, periorbital edema may not be present, but other signs such as a palpaple goiter and thyroid medication use will help in suspecting the diagnosis.

Precipitants

  1. Sepsis
  2. Bradycardia and hypothermia
  3. Cold exposure
  4. Trauma
  5. MI
  6. CHF
  7. CVA
  8. GI bleed
  9. Metabolic conditions (hypoxia, hypercapnia, hyponatremia, hypoglycemia)
  10. Burns
  11. Meds: B-blockers, sedatives, narcotics, phenothiazine, amiodarone[5]
  12. Medication non-compliance (thyroid meds)

Diagnosis

Hypothermia

  • Temperature <35.5°C (95.9°F).

Cardiovascular

Pulmonary

  • Hypoventilation
    • Early respiratory support with intubation is necessary to prevent respiratory collapse
  • Hypercapnia
    • There is often diaphragmatic dysfunction that causes worsening hypoventilation. The dysfunction is reversed after thryroid hormone administration[6]
  • Pleural Effusion
  • Upper airway obstruction from glottic edema, vocal cord edema, and macroglossia can complicate intubation.

Neurologic

Work-Up

  1. Chemistry
  2. CBC
  3. TSH, FT4, FT3
  4. Cultures
  5. LFT
  6. Cortisol level
  7. VBG
  8. CXR
  9. EKG

Lab Abnormalities

Differential Diagnosis

Treatment

Respiratory Support

  • Early mechanical ventilation will prevent resipatory collapse and severe respiratory acidosis.

Fluid Resuscitation

  • Patients are often intravsascularly depleted and have an underlying infection mandating agressive fluid resususcitation
  • In patients who are hyponatremia, be cautious with rapid correction of hyponatremia and choose an appropriate fluid
  • Hypoglycemic patients will require intravenous dextrose added into the fluids

Hypotension

  • Vasopressors will be ineffective without concomitant thyroid hormone replacement

Hormone Replacment

  • Hydrocortisone 100mg q8hr IV since there is also adrenal insufficiency present


  • Levothyroxine (T4) (generally agreed upon first line therapy)
    • Dose: 100 to 500 mcg (4mcg/kg IV) followed by 75 to 100 mcg administered IV daily until the patient takes oral replacement.[7]
    • Does require extrathyroidal conversion which can be reduced in myxedema but will have a slow steady onset of action and potentially safer in patients with coronary artery disease (CAD).
  • T3
  • Dose: 20mcg IV followed by 10mcg q8hr (Start with 10mcg if elderly or has CAD)
  • Does not require extrathyroidal conversion and has more rapid onset but may be harmful in patients with severe coronary artery disease.

Hypothermia

  • Treat with passive rewarming
  • Hypothermia will also reverse with thryoid hormone administration

Disposition

  1. Admit to ICU
  2. Endocrine consult

See Also

Source

  1. Wall CR. Myxedema coma: diagnosis and treatment. Am Fam Physician. Dec 1 2000;62(11):2485-90.
  2. Davis PJ, Davis FB. Hypothyroidism in the elderly. Compr Ther. 1984;10:17–23.
  3. Arlot S et al. Myxoedema coma: response of thyroid hormones with oral and intravenous high-dose L-thyroxine treatment. Intensive Care Med. 1991;17:16–8.
  4. Nicoloff JT et al. A form of decompensated hypothyroidism. Endocrinol Metab Clin North Am. 1993;22:279–90.
  5. Mazonson PD et al. Myxedema coma during long-term amiodarone therapy. Am J Med. 1984;77:751–4.
  6. Martinez FJ et al. Hypothyroidism. A reversible cause of diaphragmatic dysfunction. Chest. 1989;96:1059–63.
  7. Smallridge RC. Metabolic and anatomic thyroid emergencies: a review. Crit Care Med. 1992;20:276–91