Key features:
(1) history of hypothyroidism
(2) typically >= 60 years of age
(3) altered mental status (which may or may not include coma)
(4) decreased serum thyroxine (T4) and elevated serum TSH
Additional clinical findings:
(1) alopecia with coarse hair
(2) urinary retention due to bladder dystonia and distention
(3) increased diastolic blood pressure early, with hypotension late
(4) decreased deep tendon reflexes with delayed relaxation
(5) dry, doughy skin
(6) nonpitting edema
(7) decreased gastrointestinal motility with ileus and/or constipation
(8) hypoventilation
(9) hypothermia
(10) macroglossia
(11) ptosis and periorbital edema
(12) bradycardia late
Additional laboratory findings:
(1) anemia (often normochromic, normocytic) and leukopenia
(2) elevated serum CPK (from skeletal muscle)
(3) elevated serum creatinine
(4) elevated serum transaminases
(5) hypercapnia and hypoxemia, with respiratory acidosis
(6) hyponatremia
(7) hypoglycemia
(8) features of precipitating cause (for example, an acute myocardial infarction would be associated with elevated serum troponin and CK-MB).
