Epidemiological, clinical and pathological features of the unexplained sudden death clustered in the mountain area of Yunnan province in China: A retrospective study of 44 cases from 1975 to 2013  期刊论文  

Objectives: Despite significant progress has been made to understand the unusual unexplained sudden death (SD) exclusively reported from Yunnan, China (YNSD) in rainy season and mainly clustered in families, unanswered questions remain. Pathological characteristics from autopsy and their correlation with the epidemiological and clinical features were determined in this study. Methods: YNSD was defined as that 2 or more successive SD within 7 days between June and September occurred in mountain villages of YN, or one SD occurred at the same season and condition with at least 2 YNSD reported from the same place in previous year. Epidemiological and clinical information were obtained by retrospective investigation and surveillance. Informed consents for autopsies were completed. Heart (n=44), brain (n=9) and other vital organs were re-examined as necessary. The diagnosis of myocarditis, arrhythmogenic right ventricle cardiomyopathy (ARVC) and Keshan Disease (KSD) were made based on the pathological criteria of each disease. Results: A total of 44 eligible autopsy cases, accounting for 11% of the 416 YNSD from 1975 to 2013, were enrolled in this study. There were 26 and 17 cases reported in July and August from 36 rural families in 30 villages in 15 counties, respectively. All lived in the mountain areas. Number of cases were 31 of out-of-hospital death and 37 were witnessed and 23 males and 21 females, mean age of 33 (7-68) years old, 26 nationally minority and 18 Han Chinese. Occupationally of farmer in 37 and 7 children or students. No suspicious toxin and/or drug exposure could be disclosed except for eating wild mushroom in 14 cases. All were in apparently healthy previously. Nonspecific prodromal symptoms were shown in 12. Acute symptoms were witnessed in 30, crying death or dropped dead in 7 cases. No encephalic, visceral lesions or common poisoning could explain the cause of death. Based on the pathology, the most common findings were focal rather than diffuse myocarditis (lymphocytic in 19 and neutrophil in 3, respectively), ARVC (n=8), no significant pathological findings (n=5), adipositas cordis (n=5). No cases suffered from KSD and idiopathic dilated cardiomyopathy. Among 17 cases of family-clustered SD, 1 couple had ARVC, the other 2 siblings and 1 old-sister's husband had lymphocytic myocarditis. For the rest 6 pairs (12 cases), different pathological changes were found in the first and the subsequent death. Conclusions: The time-space clustering characteristics of YNSD make it unique compared to any other SD. The cardiac attack is the most likely cause of death. But it's hard to explain the causes of death in the 44 cases as the high diversity of the cardiac pathological findings. Multiple seasonal factors acted on victims with vulnerable hearts from underlying heart diseases are the major suspicious. This hypothesis needs to be further determined by searching possible pathogens, testing genetic abnormalities and detection wild mushroom toxins from postmortem specimens.