I. Definition of hypothyroid crisis Mucinous edema refers to severe hypothyroidism, and patients often have undiagnosed or untreated hypothyroidism for a long time. Mucinous edema coma is the most serious condition of hypothyroidism and is an endocrine emergency. The mortality rate of mucinous edema coma used to be as high as 85%, but recently, due to early detection and aggressive management, the mortality rate has decreased, but it is still as high as 25%. Because the manifestation of mucinous edema is not common in most patients with mucinous edema coma, and not all patients with severe hypothyroidism are in coma, so now mucinous edema coma is called hypothyroid crisis. (a) Triggers As shown in Table 1, most hypothyroid crisis occurs in winter, when the lowering of temperature reduces the threshold of ventilation. Other predisposing factors include pneumonia, sepsis, stroke, and cardiovascular disease. Infection is the second major predisposing factor, with pneumonia being the most common infection, possibly secondary to cardiovascular accidents and after airway aspiration, followed by urinary tract infections. Patients may also have slow onset of hypothyroid crisis during hospitalization for other diseases, such as occurring after hospitalization for fracture or as a result of taking some drugs that inhibit respiratory and brain functions, such as sedatives, narcotic painkillers, antidepressants, sleeping pills and anesthetics, which inhibit respiratory drive causing carbon dioxide retention and leading to coma. (B) General manifestations 1. Patients with mucinous edema exhibit hypometabolism, including dry skin, thinning hair, hoarseness, anterior tibial non-concussive swelling, large tongue, delayed Achilles reflex relaxation period and hypothermia. Abnormal laboratory tests include hyponatremia, hypoglycemia, anemia, hypercholesterolemia, elevated lactate dehydrogenase and creatine kinase, and carbon dioxide retention. The main symptoms are altered mental status, hypothermia, bradycardia, hypotension, hypoglycemia, hypoxemia, and hypercapnia. According to a report of 24 cases of hypothyroid crisis: 80% of hypothyroid crisis patients showed hypoxemia; 54% of hypothyroid crisis patients showed hypothermia (most of them had body temperature.)