Myxedema coma with normothermia

Q: 34 years old female with a known history of hypothyroidism is admitted to the ICU with hypotension, hyponatremia, hypoglycemia, bradycardia, and mental status change. Myxedema coma is suspected. Patient's temperature taken on arrival is reported as normal. The first clinical maneuver should be? - select one

A) Reconsider the diagnosis of myxedema coma

B) Recheck temperature with a reliable thermometer

C) Consult endocrinologist

D) Redraw labs to confirm hyponatremia

E) Request pharmacy to send IV vasopressin STAT

Answer: B

A frankly hypothermic body temperature may not be measured by a regularly used thermometer, and may even falsely be reported as normal. The establishment of the severity of hypothermia (choice B) is essential, as the severity of hypothermia is directly proportional to mortality in severe hypothermia.

Reconsidering the diagnosis of myxedema coma (choice A), like all diagnoses, is a prudent thing. Still, it should not bar a physician from starting the crucial time-sensitive treatment and clinical path.

Consulting an endocrinologist (choice C) is the right thing to do, too, but it will take a lot of time and may not be the first step.

Redrawing labs to confirm hyponatremia (choice D) is not required, as labs are usually reliable if they correlate with clinical signs. They can be redrawn after a period of treatment to confirm the improvement of the clinical condition.

Starting Intravenous (IV) vasopressin as a first step (choice E) is not a good choice, as it may even harm the patient, particularly if hyponatremia is present. Hyponatremia in myxedema coma is due to an impairment in free water excretion due to inappropriate excess vasopressin secretion. Concomitant adrenal insufficiency or acute kidney injury may be playing roles too. 

#endocrinology

Referencxes:

1. Mathew V, Misgar RA, Ghosh S, Mukhopadhyay P, Roychowdhury P, Pandit K, Mukhopadhyay S, Chowdhury S. Myxedema coma: a new look into an old crisis. J Thyroid Res. 2011;2011:493462. doi: 10.4061/2011/493462. Epub 2011 Sep 15. PMID: 21941682; PMCID: PMC3175396.

2. Iwasaki Y, Oiso Y, Yamauchi K, et al. Osmoregulation of plasma vasopressin in myxedema. J Clin Endocrinol Metab 1990; 70:534.

3. Liamis G, Filippatos TD, Liontos A, Elisaf MS. MANAGEMENT OF ENDOCRINE DISEASE: Hypothyroidism-associated hyponatremia: mechanisms, implications and treatment. Eur J Endocrinol 2017; 176:R15.