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myxedema coma; hypothyroid coma
Etiology:
- systemic illness superimposed on previously undiagnosed hypothyroidism
Epidemiology:
- rare
Pathology:
- severe hypothyroidism
- hemodynamic compromise
Clinical manifestations:
- poorly responsive (lethargy), unreponsive, coma
- hypotension, shock
- bradycardia
- hypothermia
- non-pitting peripheral edema, thickened skin [3]
Laboratory:
- serum TSH: very high
- serum thyroxine: very low; free thyroxine: very low
- serum glucose: hypoglycemia
- serum cortisol
- serum sodium: hyponatremia
Special laboratory:
- electrocardiogram
Radiology:
- chest X-ray: rule out pneumonia
Complications:
- aspiration pneumonia associated with hypoventilation & reduced level of consciousness
- cardiac arrhythmias associated with high-dose thyroxine
- mortality 20-15% [1]
Management:
- medical emergency
- administer IV hydrocortisone 100 mg every 8 hours [1]
- unless serum cortisol > 18 ug/dL [1]
- start prior to administration of thyroxine to treat possible comorbid adrenal insufficiency [1]
- 50-100 ug thyroxine IV every 6 hours for 24 hours
- 50-100 ug thyroxine IV daily until transition to oral thyroxine is possible [1]
- do not wait for confirmatory serum TSH prior to administration of thyroxine [3]
- monitor EKG
- ventilatory support as needed
- vasopressors as needed
- treat hypothermia [1]
- warmed intravenous fluids [1]
- treat precipitating systemic illness
General
myxedema; thyroid dermopathy (includes myxedema coma)
hypothyroidism
References
- Medical Knowledge Self Assessment Program (MKSAP) 16, 17, 18, 19.
American College of Physicians, Philadelphia 2012, 2015, 2018, 2022.
- Kwaku MP, Burman KD.
Myxedema coma.
J Intensive Care Med. 2007 Jul-Aug;22(4):224-31.
PMID: 17712058
- Geriatric Review Syllabus, 9th edition (GRS9)
Medinal-Walpole A, Pacala JT, Porter JF (eds)
American Geriatrics Society, 2016
- Geriatric Review Syllabus, 11th edition (GRS11)
Harper GM, Lyons WL, Potter JF (eds)
American Geriatrics Society, 2022
- Hampton J.
Thyroid gland disorder emergencies: thyroid storm and
myxedema coma.
AACN Adv Crit Care. 2013 Jul-Sep;24(3):325-32. Review.
PMID: 23880755
- Klubo-Gwiezdzinska J, Wartofsky L.
Thyroid emergencies.
Med Clin North Am. 2012 Mar;96(2):385-403. Review.
PMID: 22443982
- Ono Y, Ono S, Yasunaga H, Matsui H, Fushimi K, Tanaka Y.
Clinical characteristics and outcomes of myxedema coma:
Analysis of a national inpatient database in Japan.
J Epidemiol. 2017 Mar;27(3):117-122.
PMID: 28142035 Free PMC Article
- Kim J
Myxedema
N Engl J Med 2015; 372:764. February 19, 2015
PMID: 25693016
http://www.nejm.org/doi/full/10.1056/NEJMicm1403210