Thursday, October 28, 2010
Friday, October 22, 2010
Saturday, October 16, 2010
For the latter half of October I have opted to do undertake (pun intended) a 3-part series on scary sleep disorders. If all goes as scheduled, I shall deliver the final installment of this terrifying trilogy just in time for Halloweekend. And now, we begin our journey into darkness with a topic that is sure to keep you up all night…
Humans divide their time between 3 main conscious states. Wakefulness, slow-wave non-rapid eye movement sleep (NREM) and rapid eye movement sleep (REM).* Generally these states are experienced sequentially, and all is well. However, the absence or mixing of any of the states can be disorienting, debilitating and even deadly
Insomnia is the most frequently reported sleep disorder in the general population. It is defined as the inability to obtain enough sleep in order to feel rested, which can mean insufficient quantity or quality of sleep, or both. Its causes are diverse, ranging from physical problems such as obstructive sleep apnea † and restless leg syndrome‡ to social and psychological ones like night shift work and anxiety. Sometimes there is no traceable cause. As a lifelong poor sleeper, insomnia is a familiar experience that I would describe as frustrating to maddening, depending on severity. I was, however, surprised to learn that the condition could also be completely incapacitating and ultimately lethal. Such is the fate of those afflicted with fatal familial insomnia (FFI), a genetic disease as disturbing as it is rare.
FFI is, in fact, extremely rare. So much so that the mere diagnosis of a new case is often deemed worthy of its own journal article. The conditional was first described in a 1986 New England Journal of Medicine article and is believed to affect only about 40 families in the world today. It is a prion disease with autosomal dominant inheritance.§ This means that it requires only one gene with the disease-causing mutation from either parent. As with other lethal dominantly-inherited diseases, such as Huntingtons, FFI was able to persist because its symptoms generally do not manifest until after childbearing age. A parent who carries the problematic gene has a 50% chance of passing it on to any one of his or her children, but may appear to be in perfect health until things go dreadfully awry somewhere in middle to late adulthood.
Prion diseases cause degeneration within the central nervous system. FFI does its damage to the thalamus, a region of the brain that is involved, among other things, with the regulation of sleep and wakefulness. The clinical presentation of FFI begins with a progressive inability to sleep. Patients may also exhibit weight loss, difficulties with focus and memory, loss of coordination of muscles and muscle twitching. Gradually they become completely incapable of achieving slow-wave or REM sleep. During this process another curious set of symptom appears – hallucinations and the enactment of dreams during wakefulness. It is as though the dreams normally experienced during REM sleep begin to intrude into the waking state. Patients live in a gloomy, clouded limbo, neither fully asleep nor fully awake. Eventually coma and death arrive to turn off the lights. The course of this entire nightmare varies from about 8 month to 2 years. It is a long time to go without a good night’s sleep.
The name fatal familial insomnia may be a bit misleading, as it implies that its victims actually die from insomnia. Since the inability to sleep present in FFI is caused by the destruction of the thalamus, insomnia could just as easily be viewed as another byproduct of the disease. A symptom rather than a cause. It’s one of those tricky chicken-or-the-egg questions. Scientists are pretty good at designing experiments in which animals drop dead after being forcibly kept awake for weeks, but they have a harder time determining what exactly killed them. Examinations of the animals after they die tend to turn up healthy organs and no clear signs as to what physically went wrong. Sleep is a nebulous field. There is little debate that we need it, but no solid proof as to why we need it. So cherish the sleep that you can fit in to your busy schedule, lest it be brutally taken from you by a rare genetic illness.**
* REM sleep is the stage in which dreaming occurs. During REM sleep the brain is active but the body’s voluntary muscles are paralyzed, theoretically to protect the sleeper from acting out dreams.
† Obstructive sleep apnea is the blocking of airways during sleep, which leads to multiple brief awakenings during the night to obtain more air (up to 100 per hour of sleep). Sufferers may not even realize that they are losing sleep at night as they will not recall these episodes and experience their symptoms mostly in the form of daytime sleepiness. The condition also causes snoring.
‡ Restless leg syndrome was recently mocked (by me) in another article. It is a real malady, it is just not as prevalent as the pharmaceutical industry would have you believe. It is characterized by uncomfortable creepy-crawling feelings in the legs and a subsequent urge to move them. These symptoms worsen during inactive periods, for example – lying down and attempting to go to sleep.
§ A prion is a mis-folded protein that replicates itself using healthy cells, not unlike a virus. You have likely read about prions before, as they are also the culprit behind bovine spongiform encephalopathy, aka mad cow disease.
** There is no actual causal relationship between these two things. I’m just being dramatic. It’s October.
Who told you this?
Mahowald, M.W. and Schenck, C.H. 2005. “Insight From Studying Human Sleep Disorders.” Nature 437: 1279-1285.
Raggi, A. et al. 2008. “The behavioral features of fatal familial insomnia: A new Italian case with pathological verification.” Sleep Medicine 10: 581-585.
Krasnianski, A. et al. 2008. “Fatal Familial Insomnia: Clinical Features and Early Identification.” Annals of Neurology 63: 658-661.
Gallassi, R. et al. 1996. “Fatal familial insomnia: Behavioral and cognitive features.” Neurology 46: 935-939.
Medori, R. et al. 1992. “Fatal familial insomnia: A prion disease with a mutation at codon 178 of the prion protein gene.” The New England Journal of Medicine 326: 444-449.
Special thanks to Elizabeth, who first alerted me to the existence of this ailment during an evening of dancing and karaoke.
Friday, October 8, 2010
CPR stands for Cardiopulmonary Resuscitation. That means the heart and lungs are the organs of focus. The target audience for CPR is anyone experiencing cardiac arrest outside of a hospital setting. In cardiac arrest the heart stops circulating blood (and thus oxygen), causing the victim’s breathing to be impaired. This is the problem that performing CPR is aiming to fix. CPR does not address realigning dislocated shoulders, sucking venom out snake bites, escaping a burning building and countless other first-aid and wilderness-survival emergencies. You’ll need to go elsewhere to acquire those skills. However, CPR is potentially life saving to those for whom regular heartbeat and breathing have suddenly ceased.
CPR training got an overhaul in 2005. In the late 1990’s The American Heart Association (AHA) commissioned a reevaluation of existing guidelines for providing CPR, and the new guidelines were based on these findings. The biggest changes were made to how laypeople are taught to do CPR. In the past, we would have been given instructions similar to those designed for healthcare providers. However, things have been significantly dumbed down for our frail civilian brains. The reasons for this can be distilled to the observation that laypeople often forgot the intricacies of their training soon after obtaining it and then, when faced with an emergency, worried about screwing up. They lost valuable time fretting over making things worse when almost anything would have been better than nothing. With this in mind, the 2005 AHA guidelines dropped distinctions in the chest compression-to-ventilation ratio for different ages (sizes) of people. Every man, woman, child and infant now receives cycles of 30 chest compression and 2 breaths. You’re just told not to press as hard on the smaller humans (2 hands for an adult, 1 hand for a child, 2 fingers for a baby).
Another innovation by omission is that laypeople are no longer instructed to take the pulse of the suspected victim of cardiac arrest. We are only to check for breathing. No breathing = CPR. Why? Apparently we were being really slow about it. Locating a pulse is harder than it looks, and this was found to delay the initiation of CPR. With CPR, sooner is better than later.
And something is better than nothing. The rescue breathing is optional. If for whatever reason you do not feel comfortable blowing into a stranger’s mouth, the AHA says to just go ahead and do the chest compressions. There’s been much talk lately that switching to a “hands-only” protocol in general might be beneficial. The logic behind this echoes the above-mentioned concerns about bystanders being more likely to rapidly initiate CPR if it is made as uncomplicated as possible. Just press on the person’s chest in a rhythm similar to a normal heartbeat†. Also noted was that the ick-factor of the breathing might deter more germ-phobic would-be-rescuers.
A number of studies have examined this, 2 of which were recently published in the New England Journal of Medicine. Both studies were conducted by having emergency dispatchers deliver randomized different sets of instructions to callers reporting cardiac arrest emergencies: some were instructed to provide chest compression and breaths, the others chest compression only. ‡ What the authors found was the while recipients of the hands-only CPR did not fare significantly better than those who received the traditional sets of compressions and breaths, they certainly didn’t fare worse. Additionally, in one of the studies, those whose cardiac arrests had cardiac causes (as opposed to non-cardiac causes such as drug overdose) tended toward better outcomes when given just chest compressions and no breaths. It can be argued that, since at the time of a sudden cardiac arrest the body still has a decent volume of oxygen available (roughly 10 minutes worth), rescue breathing is not as important in the first few minutes and it is best to minimize interrupting chest compressions, other than to reassess breathing.
There has yet to be a consensus as to which version of CPR is best. Our class taught the chest compressions and rescue breathing version, although at least 2 members of our small class (myself and the lady who posed the question) were already aware of the debate.
I had a number of other questions for our instructor. What if the unconscious person might have choked on something (as small children are prone to do)? Answer: still perform CPR, it won’t make anything worse and might help. Can I get sued for doing this? Answer: in America, anyone can get sued for anything, but such cases are generally dismissed.
Had I consulted with others prior to attending the class, I would also have inquired if, once I got my CPR certification card, I could get sued for not performing CPR. One friend claimed to have been told something to that effect during his CPR certification, but I have yet to find any confirmation of this. Either way, I will gladly administer chest compressions to any of you who have heart attacks in my presence. Although I can’t make any promises about doing the rescue breathing.
* For our purposes here, a layperson is anyone who is not a healthcare provider, regardless of how brilliantly you did on your college biology exams.
† The EMS guy who taught our CPR class informed us that the song “Stayin’ Alive” has a suitably paced beat to it, so you can always hum the Bee Gees to yourself if you’re unsure of what a normal heart rate feels like.
‡ If you’re thinking that it sounds like people were participating in these studies without consenting, you’re absolutely correct. However, the authors assure us that ethics committees and “appropriate review boards” signed off on their methods. If it makes you feel any better, surviving participants of one of the studies were eventually informed of their contribution to science. And now you’re probably thinking, “What about the friends and families of the non-survivors?” and I just don’t have an answer for you. I’m guessing no?
Who told you this?
2005. “Overview of CPR.” Circulation 112: IV-12-IV-18.
Sayre, M.R. et al. 2008. “Hands-Only (Compression-Only) Cardiopulmonary Resuscitation: A Call to Action for Bystander Response to Adults Who Experience Out-of-Hospital Sudden Cardiac Arrest.” Circulation 117: 2162-2167.
Weisfeldt, M.L. 2010. “In CPR, Less May Be Better.” New England Journal of Medicine 363: 481-483.
Rea, T.D. et al. 2010. “CPR with Chest Compression Alone or with Rescue Breathing.” New England Journal of Medicine 363: 423-433.
Svensson, L. et al. 2010. “Compression-Only or Standard CPR in Out-of-Hospital Cardiac Arrest.” New England Journal of Medicine 363: 434-442.
Helpful and patient CPR instructor whose name I forgot.
Friday, October 1, 2010
Up until fairly recently I had assumed that the Tasmanian devil was a mythical creature, like a unicorn or a narwhal*, invented by the people at Warner Brothers. Sometime over this past summer, a friend was kind enough to rescue me from this fog of ignorance and explain that the devils not only exist, but that they exist, as their name insinuates, in Tasmania.
It would be an entertaining twist if I could report that Tasmanian devils are quiet, cuddly and sociable vegetarians, but I am bound by the facts and must therefore admit that their temperament is pretty accurately depicted by the animated character seen in Bugs Bunny cartoons of yore. The devils were given their name after European settlers observed their characteristic growling, snarling and bearing of sharp teeth. The animals are nocturnal scavengers and quarrel ferociously over their finds with others of their species. During my research for this article I listened to some audio recordings of the animals and found them to be evocative of scenes in The Exorcist.
What They Eat
As scavengers, the devils have a wide diet including but not limited to snakes, birds, fish, amphibians, smalls mammals and various carrion. They’ve been known to eat animals caught in hunters’ snares and occasionally to make off with poultry from farms, as well as helping themselves to larger livestock that were already dead.† Tasmanian devils are similarly unfussy as to cuts of meat and will eat any and all parts of their food – hair, organs, and even bones. They are, however, strictly carnivorous.
Where They Live
Tasmanian devils were once found on the Australian mainland but have since gone extinct there.‡ Today they exist in the wild only on the island of Tasmania. They travel at night in search of food. Distance traveled varies with availability of food but has been recorded at as much as 10 miles.
Birth and Death
Like kangaroos and opossums, Tasmanian devils are marsupials and females are equipped with pouches to carry their newly born offspring. Females give birth to 20 to 30 little devils at a time but bodily resources only allow for the survival of 4. Often times just 2 or 3 make it to adulthood. The animals are ready to go it alone at about 8 months and typically live in the wild for about 5 years.
Some Bad News
While their numbers climbed after they achieved protected species status in 1941, the devils encountered a new threat in the mid 90’s – Devil Facial Tumor Disease (DFTD). The disease is a contagious cancer that causes the growth of large lumps on the animal’s face. These impede eating and can eventually lead to starvation. Before you start feeling too sad, let me assure you that scientists are already on it, working with both captive breeding and genomic research in order to save the beasties from extinction. With any luck, you will still be able to see a devil on your next trip to Tasmania.
Can They Hurt You?
The Tasmanian devil has a powerful jaw and can deliver a wallop of a bite relative to its size. However they’re not that big, ranging from about 9 to 26 lbs.§ You’ll probably be fine as long as you don’t try to pick them up and incorporate them into your vacation photos.
* Kidding, kidding. Narwhals are real and will possibly be discussed at length here at some future date.
† Tasmania’s Parks and Wildlife website praises the Tasmanian devils’ consumption of farm carcasses as a way of maintaining agricultural hygiene (nobody likes blowflies). However, farmers once believed that the devils were killing livestock and made much attempt to eradicate the perceived pests until Tasmanian devils were made a protected species in 1941.
‡ There is some debate as to when this extinction occurred. Some have claimed that it was as recent as 500 years ago. However, the current opinion is that they disappeared from Australia somewhere between 3000 and 4000 years ago, which would correspond to the introduction of dingoes from Asia. In any event, Tasmanian devils were already absent from the Australian mainland by the time Europe showed up, so for once we can’t blame them.
§ For what it’s worth, they are still the world’s largest carnivorous marsupial.