Myxedema coma: challenges and future directions, a systematic survey and review

There was no systematic study on myxedema coma (MC), this review summarizes clinical research on MC conducted over the past 20 years. Publications from 2004 to 2024 were retrieved from databases and included. A total of 584 published cases and 114 unpublished cases of MC were systematically analyzed. The estimated incidence rate of MC was 0.12 (95% confidence interval [CI], 0.10%-0.14%) per million per year. Precipitating factors were identified in 77.6% (95%CI: 73.7%-81.5%) of patients with MC. The overall mortality rate was 38.8% (271/698, 95%CI: 34.9%-42.7%), with shock and multiple organ failure (MOF) being the most common causes of death. The results demonstrated that 88.9% (95%CI: 86.9%-90.9%) of patients with confirmed MC had altered mental status (AMS). Approximately 71.9% (95CI:68.0%-75.8%) of patients with MC had hypothermia, and 66.2% (95CI:62.3%-70.1%) had a heart rate < 60 bpm. Seven signs (hypoglycaemia, hypotension, hypercarbia, hoarseness, dry skin, constipation, and puffiness) showed both negative and positive predictive values below 70% and were consequently excluded from the diagnostic criteria. Combined with literature reviews and statistical analysis, proposed diagnostic criteria for MC are presented. It is generally recommended to confirm the presence of decreased FT3 and/or FT4 levels as a necessary criterion for establishing a diagnosis of MC. Early recognition, clinical suspicion, prompt thyroid hormone replacement, supportive measures, and appropriate management of coexisting problems remain the cornerstone of managing this fatal endocrine emergency. Future research directions for MC should focus on: clinical validation and refinement of diagnostic criteria, elucidating the pathophysiological mechanism underlying MC, and conducting clinical studies to compare the efficacy of different treatment regimens.