Early recognition of myxedematous respiratory failure in the elderly.

Objective: To report the clinical characteristics of myxedematous respiratory failure in the elderly and to facilitate early recognition of hypothyroidism in critically ill old patients.

Methods: Clinical characteristics of our reported 4 patients and that of 17 patients with myxedematous respiratory failure reported previously were reviewed. Demographic information, vital signs, basic laboratory studies, and blood gas analysis were compared.

Results: All 4 patients were older than 60 years and were hypoxic and hypercarbic upon presentation. All were found to have either anemia or marked electrolyte abnormalities and markedly elevated levels of thyroid-stimulating hormone once these levels were evaluated. Three of the 4 patients presented with profound lethargy and/or constipation, slowed intellectual ability, and dry skin.

Conclusions: Early recognition of hypothyroidism in elderly patients with myxedematous respiratory failure is crucial to prognosis. Whereas hypothermia, myxedema, and a history of thyroid disease mandate the thyroid function tests in patients with type 2 respiratory failure, the following 5 elements also warrant the thyroid function tests: bradycardia, anemia, hyponatremia, pleural or pericardial effusion, and a history of weight gain. Where mechanical ventilation has been applied, patients with difficult weaning from ventilator support should also be evaluated and screened for hypothyroidism.