132 Sudden Unexplained Death Syndrome (Asian)
Sudden unexplained death syndrome (SUDS) occurs when a relatively young healthy person, usually male and Asian, dies unexpectedly while sleeping. The victim has no known antecedent illnesses, and there are no factors that might precipitate cardiac arrest.
At autopsy, no cause of death can be identified in the heart, lung, or brain. Postmortem toxicologic screening tests reveal no poisons. A sudden fatality during sleep in a previously healthy member of an ethnic group subject to SUDS, but whose death is not investigated with an autopsy, is defined as a presumptive case of SUDS.Distribution and Incidence
SUDS has occurred in the 1980s among Southeast Asian refugees and immigrants in the United States, mainly among Laotians, Hmong, Kampucheans, and Filipinos. In Asia, SUDS has been described in the Japanese and Filipino medical literature and is also observed in refugee camps in Thailand. In 1983 the death rate ascribed to SUDS in the 25- to 44-year age group of Laotian and Hmong males in the United States, 87 per 100,000, was comparable to the sum of the four leading causes of natural death among other U.S. males in that age group. The incidence of SUDS has decreased since 1983, and there is evidence that the longer a refugee has been in the United States, the lower the risk.
Epidemiology
The first comprehensive report of SUDS in the United States was published by the Centers for Disease Control (CDC) on December 4, 1981; it described 38 victims, all Southeast Asian refugees. All but one of the cases were males: 25 Hmong, 8 Laotian, 4 Vietnamese, and 1 Kampuchean. Median period of time in the United States was 5 months (range, 5 days to 52 months) before death. Geographic distribution of the deaths reflected the distribution of the Southeast Asian refugees in the United States. The deaths occurred between 9:30 P.M.
and 7:00 A.M.Clinical Manifestations and Pathology
The victims whose deaths were witnessed by relatives appeared to be asleep prior to death or were just falling asleep. None of them had complained of illness or symptoms before going to bed, and all were considered by family members to have been in good health.
Witnesses of SUDS deaths become aware of abnormal breathing sounds, in some cases preceded by a brief groan. Victims cannot be aroused. Terminal respirations are said to be labored and deep, irregular and without wheezing or stridor. The victims remain flaccid during these events, although a few are described as having tonic rigidity. Some of the victims are incontinent of urine or feces. Witnesses recall no signs of pain or terrifying dreams. A few of the victims who are still alive when paramedics reach them are found to be in ventricular fibrillation.
Interviews with family members yield no clues as to why the victims have died. Spouses have not noted symptoms consistent with sleep apnea syndrome.
Etiology
In discussing the significance of SUDS cases, CDC investigators note that they “may constitute a new syndrome” because of the differences in the epidemiological pattern between these cases and other victims of sudden death. The quickness of the deaths is unusual, and there is a lack of any ascribed cause after extensive postmortem investigation.
The etiology of SUDS remains unknown. In 1982 researchers at the CDC performed a case control study using the first 26 cases of SUDS among Hmong and Laotians in the United States. Results were meager. No single variable was found that differentiated cases from controls. The victims tended to have been in the country less than 6 months, to have left Laos less than 3 years earlier, to have spent a greater proportion of their income on housing, and to have acquired fewer possessions in the United States than had other immigrants. Although cases had similar amounts of English training, they had less job training.
Cases had gained weight less frequently than controls and lost weight more frequently. The authors of the study concluded that factors that enhance emotional stress or result from such stress are a “possible precipitating element in these deaths.”History and Geography
Sudden death in healthy individuals is a phenomenon that has occurred throughout history and in many cultures. Because of their sudden and unexpected nature, many of these deaths have been attributed to supernatural or psychological causes. There has been speculation that SUDS among Southeast Asian refugees in the United States may be triggered by such factors as stress, night terror, evil spirits, or culture shock.
Yet a number of older reports in the medical literature of the Philippines have identified a sudden nocturnal death syndrome known as Bangungut. Previously healthy males die during the night, making moaning, snoring, or choking noises. Bangungut means “to rise and moan in sleep” in Tagalog, reflecting the folk belief that the deaths are caused by terror from nightmares. The victims are men 20 to 50 years old. No consistent cause has been found for these sudden deaths, even though they have been extensively evaluated with autopsies. The main postmortem finding is hemorrhagic pancreatitis, a condition most observers believe is not a cause of the syndrome but, rather, an effect after death.
Physicians in the Emergency Department at Philippine General Hospital in Manila state that they see numerous cases of SUDS every year. The typical profile of a victim is a young male adult with a stocky build, usually a poorly educated construction worker who migrated from the Visayan Islands to work in Manila and who had either been on a drink- _ ing spree shortly before sleeping or had just eaten a fatty meal prior to retiring for the night. The victim is brought to the Emergency Room by fellow workers who are unable to wake him, but who remember his moaning and groaning in sleep.
Nearly universally Filipinos have heard about Bangungut and believe in its authenticity. Many of them describe experiences as children being assigned to watch over their fathers’ afternoon naps.Similar episodes of sudden death among Filipinos living in the Hawaiian Islands were described in the medical and popular literature during 1930-60.
In Japan, there is a disease referred to as pokkuri, which is a sudden death similar to those described in Southeast Asians in the United States and in the Philippines. A study of 18,515 consecutive autopsies in Japan found cardiac death of unknown etiology in 76 cases. Almost all of these deaths occurred in young men who had been considered to be in good health and who died suddenly during sleep. Some Japanese pathologists believe that the cause of death is a fulminant deletion of myoglobin from myocardial fibers during a state of acute cardiac failure.
An American anthropologist and epidemiologist has studied SUDS in the refugee camps in Thailand. Although autopsies are not common in such settings, the deaths were very similar to SUDS deaths occurring among similar refugees in the United States.
Emotional trauma, voodoo, spirits, and magic have all been suggested as important factors for sudden unexplained death in folk cultures. Modern biomedical beliefs prescribe that psychological factors cannot cause deaths per se, but may trigger a fatal event. A different emphasis occurs in reports of sudden death among persons living in cultures where the concept of psychological sudden death has greater currency than in scientific Westernized cultures. For example, in Australia there was a belief among the northern Aborigines that a person who has been pointed at with a bone will die as a result. A government surgeon among the people of that region in 1897 wrote that he had witnessed three or four such cases. A phenomenon of wishful dying has been described among rural Bantu people in South Africa.
Several studies of the Hmong, the group hardest hit by SUDS in the United States, have proposed psychological triggers as explanations for their deaths.
An extensive cultural study of SUDS focused on Hmong religion and its relationship to health concepts, but no correlation could be found between the deaths and religious preference, degree of belief in traditional religion, or anxiety over religious questions. The author concluded that one possible triggering mechanism for SUDS might be overwhelming and inescapable stress. Another study conducted in the United States by two anthropologists also considered stress as a potential trigger in SUDS. The authors interviewed relatives of 28 victims of the syndrome and concluded that night terror might have contributed to their deaths. The researchers speculated that such terror was brought on by exhaustion, culture shock, family quarrels, or even the violent images found on television.Neal R. Holtan
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