Myxedema coma: Difference between revisions

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**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>
**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>
**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).  
**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'''
*'''T3'''  
*Dose: 20mcg IV followed by 10mcg q8hr (Start with 10mcg if elderly or has CAD)
**Dose: 20mcg IV followed by 2.5-10mcg q8hr<ref>Jonklaas J, Bianco AC, Bauer AJ, Burman KD, Cappola AR, Celi FS, et al. Guidelines for the treatment of hypothyroidism: prepared by the american thyroid association task force on thyroid hormone replacement. Thyroid. 2014 Dec. 24 (12):1670-751.</ref>(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.
**Does not require extrathyroidal conversion
**More rapid onset but may be harmful in patients with CAD
*American Thyroid Association recommends combination therapy T4 with T3
 
===Hypothermia===
===Hypothermia===
*Treat with passive rewarming  
*Treat with passive rewarming  

Revision as of 20:06, 18 February 2016

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

Clinical Features

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

Differential Diagnosis

Diagnosis

Work-Up

  • Chemistry
  • CBC
  • TSH, FT4, FT3
  • Cultures
  • LFT
  • Cortisol level
  • VBG
  • CXR
  • EKG

Lab Abnormalities

Management

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 2.5-10mcg q8hr[8](Start with 10mcg if elderly or has CAD)
    • Does not require extrathyroidal conversion
    • More rapid onset but may be harmful in patients with CAD
  • American Thyroid Association recommends combination therapy T4 with T3

Hypothermia

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

Disposition

  • Admit to ICU

See Also

References

  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
  8. ↑ Jonklaas J, Bianco AC, Bauer AJ, Burman KD, Cappola AR, Celi FS, et al. Guidelines for the treatment of hypothyroidism: prepared by the american thyroid association task force on thyroid hormone replacement. Thyroid. 2014 Dec. 24 (12):1670-751.
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