Myxedema coma: Difference between revisions

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==Background==
==Background==
*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>
*[[Hypothyroidism]] + [[AMS|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>
*Majority of the patients will be > 60yo<ref>Davis PJ, Davis FB. Hypothyroidism in the elderly. Compr Ther. 1984;10:17–23.</ref>  
*Majority of the patients > 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
**Usually occurs after precipitating incident in patient with untreated hypothyroidism <ref>Thiessen, M. (2018). Thyroid and Adrenal Disorders. Rosen's Emergency Medicine (9th ed.). Philadelphia, PA: Elsevier/Saunders.</ref>
*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>
*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>
*Untreated mortality approaches 100% <ref>Thiessen, M. (2018). Thyroid and Adrenal Disorders. Rosen's Emergency Medicine (9th ed.). Philadelphia, PA: Elsevier/Saunders.</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.
*~50% of cases become evident '''''after''''' admission
*Severe hypothyroidism may be first time presentation of hypothyroid<ref>Nicoloff JT et al.  A form of decompensated hypothyroidism. Endocrinol Metab Clin North Am. 1993;22:279–90.</ref>


===Precipitants===
===Precipitants===
*Bradycardia and hypothermia
*[[Bradycardia]] and [[hypothermia]]
*Burns
*[[Burns]]
*[[CHF]]
*[[CHF]]
*[[CVA]]
*[[CVA]]
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*[[GI bleed]]
*[[GI bleed]]
*Metabolic abnormalities ([[hypoxia]], [[hypercapnia]], [[hyponatremia]], [[hypoglycemia]])
*Metabolic abnormalities ([[hypoxia]], [[hypercapnia]], [[hyponatremia]], [[hypoglycemia]])
*Medications: 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>
*Medications: [[Beta blockers]], [[sedatives]], [[opioids]], [[phenothiazines]], [[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)
**Especially medications with CNS depressant effect <ref>Thiessen, M. (2018). Thyroid and Adrenal Disorders. Rosen's Emergency Medicine (9th ed.). Philadelphia, PA: Elsevier/Saunders.</ref>
*Medication non-adherence (thyroid meds)
*[[MI]]
*[[MI]]
*[[Sepsis]]
*[[Sepsis]]
*Trauma
*[[Trauma]]
*[[PE]]


==Clinical Features==
==Clinical Features==
===Hypothermia===
===[[Hypothermia]]===
*Temperature <35.5°C (95.9°F).  
*Temperature <35.5°C (95.9°F).  
===Cardiovascular===
===Cardiovascular===
*[[Bradycardia]]
*[[Bradycardia]]
*[[Hypotension]]
*[[Hypotension]]
*[[Pericardial effusion]]
===Pulmonary===
===Pulmonary===
*Hypoventilation
*Hypoventilation, [[hypercapnia]]
**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 thyroid hormone administration<ref>Martinez FJ et al. Hypothyroidism. A reversible cause of diaphragmatic dysfunction. Chest. 1989;96:1059–63.</ref>
**There is often diaphragmatic dysfunction that causes worsening hypoventilation.  The dysfunction is reversed after thyroid hormone administration<ref>Martinez FJ et al. Hypothyroidism. A reversible cause of diaphragmatic dysfunction. Chest. 1989;96:1059–63.</ref>
**Early respiratory support with intubation may be necessary to prevent respiratory collapse
*[[Hypoxia]]
*[[Pleural Effusion]]
*[[Pleural Effusion]]
*Upper airway obstruction from glottic edema, vocal cord edema, and macroglossia can complicate intubation.
*Upper airway obstruction from glottic edema, vocal cord edema, and macroglossia can complicate intubation.
===Neurologic===
===Neurologic===
*[[Altered mental status]]/[[Coma]]
*[[Altered mental status]]/[[Coma]] due to CO2 narcosis
*[[Coma]] is very rare
*Pseudomyotonic "hung up" deep tendon reflexes
**Particularly Achilles reflex
**Relaxation phase of DTR twice as long as contraction phase
*Neuropsychiatric symptoms <ref>Thiessen, M. (2018). Thyroid and Adrenal Disorders. Rosen's Emergency Medicine (9th ed.). Philadelphia, PA: Elsevier/Saunders.</ref>
**[[Depression]]
**[[Psychosis]]


==Differential Diagnosis==
==Differential Diagnosis==
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*[[Sepsis]]
*[[Sepsis]]


==Diagnosis==
==Evaluation==
===Work-Up===
===Work-Up===
*TSH, FT4, FT3
**In primary hypothyroidism TSH will be elevated and T4 and T3 will be low
**If the patient has secondary hypothyroidism (Pituitary dysfunction) the TSH may be low or normal and T4 and T3 will be low
*Chemistry
*Chemistry
**[[Hyponatremia]]
**[[Hypoglycemia]]
**+/- [[renal failure|Elevated creatinine]]
*CBC
*CBC
*TSH, FT4, FT3
**Mild [[anemia]], [[leukopenia]]
*Cultures
*[[Blood cultures]]
*LFT
*[[LFTs]]
**Elevated transaminases
*[[Rhabdomyolysis|Elevated CPK]]
*Cortisol level  
*Cortisol level  
*VBG
*[[VBG]]/ABG
*CXR
**[[Hypercapnia]]
*EKG
**Hypoxia
 
*Lipid levels
===Lab Abnormalities===
**Hypercholesterolemia
*Abnormal Thyroid Hormone Levels
*[[CXR]]  
**In primary hypothyroidism then TSH will be elevated and T4 and T3 will be low
*[[ECG]]  
**If the patient has secondary hypothyroidism (Pituitary dysfunction) the TSH can be low or normal and T4 and T3 will be low
**Sinus bradycardia
*[[Anemia]]
**Non-specific ST-T wave changes
*[[Rhabdomyolysis|Elevated CPK]]
**Prolonged QTc
*[[Renal Failure|Elevated creatinine]]
**Ventricular dysrhythmias
*Elevated transaminases
*Bedside [[cardiac US]] for [[pericardial effusion]]
*[[Hypercapnia]]
*Hyperlipidemia
*[[Hypoglycemia]]
*[[Hyponatremia]]
*[[Hypoxia]]
*Leukopenia
*Respiratory acidosis


==Management==
==Management==
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*Early mechanical ventilation will prevent respiratory collapse and severe respiratory acidosis.  
*Early mechanical ventilation will prevent respiratory collapse and severe respiratory acidosis.  
===Fluid Resuscitation===
===Fluid Resuscitation===
*Patients are often intravsascularly depleted and have an underlying infection mandating aggressive fluid resuscitation
*Often intravascularly depleted
*In patients who are hyponatremia, be cautious with rapid correction of hyponatremia and choose an appropriate fluid  
**May have underlying illness causing dehydration
*Hypoglycemic patients will require intravenous dextrose added into the fluids
*In patients who are hyponatremic, be cautious with rapid correction of hyponatremia
===Hypotension===
**Consider fluid restriction
*Use D5NS if hypoglycemic
 
===[[Hypotension]]===
*[[Vasopressors]] will be ineffective without concomitant thyroid hormone replacement
*[[Vasopressors]] will be ineffective without concomitant thyroid hormone replacement
===Hormone Replacement===
===Hormone Replacement===
*'''Hydrocortisone''' 100mg q8hr IV since there is also adrenal insufficiency present
*'''[[Levothyroxine]] (T4)''' (generally agreed upon first line therapy)
**Alternative: Dexamethasone 2-4mg q12hrs (will not affect cortisol level or ACTH stimulation test)
*'''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.<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
**Does require extrathyroidal conversion which can be reduced in myxedema but will have a slow steady onset of action
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**Does not require extrathyroidal conversion
**Does not require extrathyroidal conversion
**More rapid onset but may be harmful in patients with CAD
**More rapid onset but may be harmful in patients with CAD
===Hypothermia===
 
*Treat with passive rewarming  
===[[Adrenal Insufficiency]]===
*Hypothermia will also reverse with thryoid hormone administration
*[[Hydrocortisone]] 100 mg IV q8h for possible concomitant adrenal insufficiency
**Alternative: [[dexamethasone]] 2-4mg q12hrs (will not affect cortisol level or ACTH stimulation test)
 
===[[Hypothermia]]===
*Treat with passive rewarming
*[[Hypothermia]] will also reverse with thyroid hormone administration
*Avoid mechanical stimulation
*Do not actively rewarm:
**Usually are volume depleted
**Rapid peripheral vasodilation may induce worsening hypotension


==Disposition==
==Disposition==
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<references/>
<references/>


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

Revision as of 16:37, 28 September 2019

Background

  • Hypothyroidism + mental status changes/coma + hypothermia + precipitating stressor[1]
  • Majority of the patients > 60yo[2]
  • Occurs in 0.1% of patients with hypothyroidism
    • Usually occurs after precipitating incident in patient with untreated hypothyroidism [3]
  • Mortality may be as high as 60%[4]
  • Untreated mortality approaches 100% [5]
  • ~50% of cases become evident after admission
  • Severe hypothyroidism may be first time presentation of hypothyroid[6]

Precipitants

Clinical Features

Hypothermia

  • Temperature <35.5°C (95.9°F).

Cardiovascular

Pulmonary

  • Hypoventilation, hypercapnia
    • There is often diaphragmatic dysfunction that causes worsening hypoventilation. The dysfunction is reversed after thyroid hormone administration[9]
    • Early respiratory support with intubation may be necessary to prevent respiratory collapse
  • Hypoxia
  • Pleural Effusion
  • Upper airway obstruction from glottic edema, vocal cord edema, and macroglossia can complicate intubation.

Neurologic

Differential Diagnosis

Evaluation

Work-Up

Management

Respiratory Support

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

Fluid Resuscitation

  • Often intravascularly depleted
    • May have underlying illness causing dehydration
  • In patients who are hyponatremic, be cautious with rapid correction of hyponatremia
    • Consider fluid restriction
  • Use D5NS if hypoglycemic

Hypotension

  • Vasopressors will be ineffective without concomitant thyroid hormone replacement

Hormone Replacement

  • 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.[11]
    • Does require extrathyroidal conversion which can be reduced in myxedema but will have a slow steady onset of action
    • Potentially safer in patients with CAD
    • American Thyroid Association recommends treatment with both T4 and T3[12]
  • T3 20mcg IV followed by 2.5-10mcg q8hr
    • Start with 10mcg if elderly or has CAD
    • Does not require extrathyroidal conversion
    • More rapid onset but may be harmful in patients with CAD

Adrenal Insufficiency

  • Hydrocortisone 100 mg IV q8h for possible concomitant adrenal insufficiency
    • Alternative: dexamethasone 2-4mg q12hrs (will not affect cortisol level or ACTH stimulation test)

Hypothermia

  • Treat with passive rewarming
  • Hypothermia will also reverse with thyroid hormone administration
  • Avoid mechanical stimulation
  • Do not actively rewarm:
    • Usually are volume depleted
    • Rapid peripheral vasodilation may induce worsening hypotension

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. Thiessen, M. (2018). Thyroid and Adrenal Disorders. Rosen's Emergency Medicine (9th ed.). Philadelphia, PA: Elsevier/Saunders.
  4. 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.
  5. Thiessen, M. (2018). Thyroid and Adrenal Disorders. Rosen's Emergency Medicine (9th ed.). Philadelphia, PA: Elsevier/Saunders.
  6. Nicoloff JT et al. A form of decompensated hypothyroidism. Endocrinol Metab Clin North Am. 1993;22:279–90.
  7. Mazonson PD et al. Myxedema coma during long-term amiodarone therapy. Am J Med. 1984;77:751–4.
  8. Thiessen, M. (2018). Thyroid and Adrenal Disorders. Rosen's Emergency Medicine (9th ed.). Philadelphia, PA: Elsevier/Saunders.
  9. Martinez FJ et al. Hypothyroidism. A reversible cause of diaphragmatic dysfunction. Chest. 1989;96:1059–63.
  10. Thiessen, M. (2018). Thyroid and Adrenal Disorders. Rosen's Emergency Medicine (9th ed.). Philadelphia, PA: Elsevier/Saunders.
  11. Smallridge RC. Metabolic and anatomic thyroid emergencies: a review. Crit Care Med. 1992;20:276–91
  12. 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.