Mystery Deaths Plague Coroners
Human skulls used by students for experiments are shown on a shelf inside the forensic anthropology lab at Western Carolina University, Monday July 24, 2006, in Cullowhee, N.C.
Credit: AP Photo/Alan Marler

WASHINGTON—Edge-of-your-seat story lines ripped from the headlines and saturated with mind-taxing scientific clues are the hallmarks of forensic shows such as "CSI: Crime Scene Investigation."

While the coroners’ sleuthing can typically hone in on a cause of death by the show’s end, real medical examiners across the country are puzzled by a certain number of cases that cross their examination tables.

Now scientists are starting to get a handle on some of the trends. About 3 percent of all bodies autopsied in the United States get classified as “undetermined cause of death,” said Gregory Davis, a forensic pathologist at the University of Alabama at Birmingham and a Jefferson County, Alabama, coroner and medical examiner. Davis led a panel discussion featuring forensic pathologists who spoke here this week at a meeting of the American Physiological Society (APS).

“Undetermined is a one-word way of saying, 'I’ve done everything I know to do and I can’t figure out the cause of death,'” Davis said.

But recently, intensive medical probing is pointing to three types of explanations for the deaths, explanations that can resolve at least a small subset of the mysteries—drugs, police restraint techniques and something to do with sleeping babies.

Drug deaths

Davis and his colleagues, who carried out a study of deaths in Jefferson County in Birmingham, found that people who died of an undetermined cause were four times more likely to have a history of drug abuse when compared to the control group. The study is detailed in the March 2005 issue of the Journal of Forensic Science. “There’s something about using drugs, even if you can’t find the drugs in your system, that makes you susceptible to sudden death," he said

“Several times a year, a case will come in to our office, and it’ll be a young person, and somehow or another I’ll know the person had a history of using drugs,” Davis told LiveScience.

A few years ago, Davis examined the body of a medical student who had come to town to take a medical-exam review class. The guy was found dead in the bathroom of his hotel room.

The student’s friends told Davis, “He partied harder than any other guy in our class. We know he took stuff to stay awake and stuff for fun, and there’s no telling what you’re going to find in his system.”

But Davis found no traces of drugs, and the autopsy didn’t turn up any clues that would suggest a cause of the lethal collapse—another undetermined death.

Drug genetics

The interaction of drugs as well as an individual’s ability to metabolize different drugs are lines of research that Davis thinks show promise in explaining the drug-related mystery cases.

Recent research has shown that mutations to a gene dubbed CYP2D6 could cause some individuals to break down drugs either much slower or quicker than the “normal population.” Those with the gene variant that causes sluggish metabolism can accumulate five-times more of a drug in their systems than doctors would expect. That could make a non-lethal dose of say methadone or the pain drug OxyContin deadly. Up to 60 percent of methadone deaths may be linked to such a genetic mutation, according to one recent study.

“I’m not naïve enough to think people would stop using cocaine if you told them they were genetically unfit to do so. But nevertheless it would help us in trying to understand why some people die and others do not,” Davis said.

Stun science

Another post-mortem conundrum involves the use of restraint and force, including when police officers place a suspect into a chokehold or use pepper spray.

An estimated 50 to 150 deaths per year are associated with restraint in the United States, according to the Harvard Center for Risk Analysis. However, few states require the reporting of deaths linked to restraint. So any estimates for police restraint-related deaths are iffy.

“It’s possible that the actions of the restrainers played a role in the death, but it’s also possible that the actions of the restrainers didn’t play a role in the death,” said James Keith Pinckard, a forensic pathologist at the Southwestern Institute of Forensic Science in Dallas and at the University of Texas Southwestern Medical Center.

One restraint technique that has entered the spotlight is the use of Tasers, devices that work in a similar manner to stun guns, but let officers shoot from a farther distance. Once the cross-hairs latch onto a target, voltage enters the person's body and causes the muscles to contract uncontrollably, leading to temporary paralysis.

Since June 2001, more than 150 people have died after being struck by Tasers, with 61 of those deaths occurring in 2005, according to Amnesty International. Autopsies have revealed other factors, such as a phenomenon called excited delirium, that may have contributed to the deaths.

“I think what we have [is] a subset of sudden deaths that occur in association with restraint of a very agitated suspect, and a lot of those cases are actually cases of excited delirium. We usually see excited delirium in cases that involve drugs," Pinckard said.

Hyped up

The term "excited delirium," which is not recognized by the American Medical Association (AMA) as a medical or mental-health condition, emerged in the 1980s to explain sudden deaths while in police custody, the same era during which cocaine use ramped up.

Excited delirium does have a profile. It is embodied by a typical “COPS” case in which an unruly suspect “goes whack,” tearing off clothes, kicking and screaming, seemingly incoherent,.

Pinckard says the suspect generally has cocaine or another drug in their system and shows symptoms such as an increase in heart rate, insensitivity to pain and great strength—the latter two features making restraint even more difficult for officers. Pinckard suggests this vicious cycle of restraint-causing-excited delirium-causing-more-restraint could lead to physiologic changes that make a person more susceptible to dying.

A recent study published last year in the journal Prehospital Emergency Care found that of 75 Taser-related deaths, nearly half had cardiovascular disease and about 80 percent had an illegal substance in their blood. Three-quarters were diagnosed as having excited delirium. The scientists concluded that the use of a Taser was either a potential or contributory cause of death in more than one-quarter of the cases.

Infant deaths

In deaths of infants under the age of one, another word for “undetermined” is “SIDS,” or sudden infant death syndrome, explained Amy Gruszecki, a forensic pathologist at the University of Texas Southwestern Medical Center and the Southwestern Institute of Forensic Science.

Scientists have long puzzled over the actual cause of SIDS, with theories including heart problems, a faulty nervous system and a scenario in which the baby loses the ability to breathe—called asphyxia.

None of the theories has been proven. “By saying an infant died of SIDS, we’re saying we don’t know why the infant died,” Gruszecki said.

The pattern of blood pooling beneath the baby’s skin can suggest suffocation. In one case she described, the infant’s skin around the mouth and nose was ghost-white, indicating those areas had been pressed up against the mattress or pillow. The baby likely wasn’t able to breathe.

Gruszecki finds other potential crime-scene clues. For instance, an infant’s crib could be chock full of blankets, pillows and stuffed animals—objects that up the chances of suffocation. Also whether the infant had been in bed with parents can be a clue.

“Inadvertently, a parent’s arm or something lands on the infant at night, and as you know your arm is heavy,” Gruszecki said. “It’s too much for the infant to try to breathe against.”

She added, “This is very hard for families, because the best I can do as a forensic pathologist is say ‘I don’t know why your child died, but I can tell you, you shouldn’t be sleeping with your children.’”

Gruszecki would like to find some sort of chemical marker that is specific to asphyxia.