X-Ray Specs

Because I have a (relatively mild) form of autoimmune arthritis, I've had a lot of x-rays in my life. I'm very familiar with my skeleton, and sometimes read diagnostic radiology journals online for fun.

This past fall, I took an introductory course in Principles of Epidemiology. We were discussing study design, and the issue of exclusion criteria. In one of our examples, subjects with spondylitis (my particular form of arthritis) were excluded from a study about bladder cancer. My professor asked why people with this condition might be excluded from the study. Of course, my hand shot up immediately because I knew the answer: multiple x-rays. That is, people with spondylitis have an abnormal amount of x-rays in their pelvic and hip region and are at a higher risk for bladder cancer. They don't represent subjects with 'normal' exposure.

After this class it suddenly occurred to me that I was in this higher risk category. I had never really thought about my condition in this way before. To date, while it's been irritating and has had an impact on my life to an extent, it never really made me feel anxious about my overall health prospects because my case is comparatively mild and while there's no cure, it's probably not going to kill me. I'm much more afraid of swine flu, or cancer, or Hanta virus, or water scarcity causing global unrest.

But suddenly I've been much more cognizant of the number of x-rays that I am prescribed. Rheumatologists love to send me to the radiology lab--dentists love to give me the bitewing x-rays--and of course there are mammograms (and while the researchers are arguing about whether women should start at age 40 or 50 for annual screening mammograms, most obgyns follow the recommendations that send patients at age 40).

So I've spent the last week or so reading up on radiation and risk, and found that there are some interesting tools that one can use to calculate your annual radiation dose.

Here is the EPA's calculator:


Here is one from the American Nuclear Society:


And yet another one by the Neighborhood Environmental Watch Network:


Some of the questions they ask to calculate exposure are pretty interesting. I'm not sure, for example, if I live within 50 miles of a nuclear power plant or a coal-fired power plant. I never really thought about how living in the Colorado Plateau gives you 63 mrems a year (as opposed to 16 mrems on the Atlantic coast). Having a gas camping lantern gives you 0.2 mrems annually and sharing a bed with someone gives you 1 mrem.

Here's what the American Nuclear Society says about dose:
The average dose per person from all sources is about 360 mrems per year. It is not, however, uncommon for any of us to receive far more than that in a given year (largely due to medical procedures we may undergo). International Standards allow exposure to as much as 5,000 mrems a year for those who work with and around radioactive material.
Because of my x-rays, my dose is twice as much as the norm. But I'm comforted by the fact that it's 4,373.93 rmems less than the allowable annual maximum permissible dose under the (somewhat frighteningly generous) International Standards.


CDC on Twitter

I must have died and gone to alarmists' heaven. You can now receive emergency alerts from the CDC on Twitter.


Climate Change Apocalypse: 'Extremely Frightening and Turbulent'

I never really thought of global warming as a public health issue...until now. Expect many more updates about my new favorite fear.

Thanks to Lydia M. for the warning:

CLIMATE: Warming may be world's biggest health threat -- study (Thursday, May 14, 2009)

Global warming has surpassed infectious disease, poverty and water shortages as the largest threat to public health, according to a new study from climatologists and medical professionals.

While poorer countries will be the first to feel the effects of a changing climate -- such as exacerbated food and water shortages and humanitarian crises of environmental refugees -- the problem will later cause real and lasting damage in wealthier Western nations, said Anthony Costello, a pediatrician at University College London, which conducted the report published today in The Lancet journal.

"Climate change is a health issue affecting billions of people, not just an environmental issue about polar bears and deforestation," Costello said. "We are setting up a world for our children and grandchildren that may be extremely frightening and turbulent."

The researchers said disruptions in climate could cause food, water and energy shortages and population shifts, resulting in wars over increasingly scarce resources (Cortez/Morales, Bloomberg, May 14). -- PR


Not a Fan of Watersports: N. fowleri

Sometimes people are like, Kim, why'd you start this blog? And I'm like, because where else can I describe my fear of Naegleria fowleri and how it keeps me out of lakes?

With summer coming up, I thought it was time for a PSA about my least favorite protist. Note that it has all of the features that I love to hate the most--it's rapidly fatal. Cases typically cause death within a week. And most horrible to my ears are these two words: delayed diagnosis.

Luckily, there's a way to avoid this brain-eating amoeba: stay out of fresh water lakes, especially when the weather is hot! And if you do have to wade into such a body of water, don't let it get up your nose, because that's how it gets you!

It's rare, for sure, but I'm not taking any chances:

'Naegleria fowleri, a free-living ameba, is the causal agent of primary amebic meningoencephalitis (PAM), which is an acute, fulminant, and rapidly fatal CNS infection. PAM develops within several days of exposure to the contaminated water source and typically causes death within 1–2 weeks after admittance to the hospital. Few individuals survive the infection, partly because of its rapid onset and partly because of delayed diagnosis.'


Facts about Viruses - Swine Flu (NYT)

The NYT had a great piece last Tuesday about viruses and Swine Flu. Here's part of it:

"The current outbreak shows how complex and mysterious the evolution of viruses is. Some viruses use DNA, like we do, to encode their genes. Others, like the influenza virus, use single-strand RNA. But viruses all have one thing in common, said Roland Wolkowicz, a molecular virologist at San Diego State University: they all reproduce by disintegrating and then reforming.

A human flu virus, for example, latches onto a cell in the lining of the nose or throat. It manipulates a receptor on the cell so that the cell engulfs it, whereupon the virus’s genes are released from its protein shell. The host cell begins making genes and proteins that spontaneously assemble into new viruses. 'No other entity out there is able to do that,” Dr. Wolkowicz said. “To me, this is what defines a virus.'

The sheer number of viruses on Earth is beyond our ability to imagine. “In a small drop of water there are a billion viruses,” Dr. Wolkowicz said. Virologists have estimated that there are a million trillion trillion viruses in the world’s oceans. A tank of 100 to 200 liters of sea water may hold 100,000 genetically distinct viruses.

Viruses are diverse because they can mutate very fast and can mix genes. They sometimes pick up genes from their hosts, and they can swap genes with other viruses. Some viruses, including flu viruses, carry out a kind of mixing known as reassortment. If two different flu viruses infect the same cell, the new copies of their genes get jumbled up as new viruses are assembled."

Read the whole story:


Some Thoughts about ALS, BFS, and Darcy Wakefield

About three years ago I developed this total irrational fear that I was developing ALS. It wasn't totally out of the blue; a grad school friend/acquaintance of mine, Darcy Wakefield, had died that year at age 35 from ALS. Her death really threw me. She was super-athletic and just kind of low-key and cool and quietly accomplished, the last person you'd expect to have to suffer such a terrible and rare disease. Her son was 2 or 3 when she passed away, and she'd been paralyzed nearly since his birth.

That summer was incredibly hot in LA, and I fainted one night outside a Mexican restaurant and had to be taken to the ER and evaluated for a seizure disorder (it turned out to be just dehydration). I then started having terrible panic episodes, and was positive that I had ALS. I was terrified all the time. My muscles were twitching and I had periods of numbness in my leg where I had trouble walking and climbing stairs. I sought comfort on the AboutBFS online forum (BSF stands for 'benign fasciculation syndrome,' which is, as the name suggests, a benign syndrome in which your muscles contract and twitch--but because of the similar symptomology to ALS, at least in the beginning of the disease, BFS sufferers are all really paranoid about ALS (on the site, they won't even write it out and refer to it as AL* or A*S or 'the disease'). Mind you, there's no real evidence that BFS leads to or is a risk factor for ALS. There is some minor overlap of symptoms, but most of what people with BFS suffer is different in nature than early onset of ALS. It just feels dire.

Anyway, after a few months, my twitching and numbness resided and my doctor figured I might have done some nerve damage exercising which caused the bodily uproar. With rest, and, I admit, a pretty good arsenal of anti-anxiety medication, I recovered and was fine.

For the past couple weeks recently, I've had a return of my twitching, except this time in my eardrums. Tonight I went back and visited AboutBFS and it was pretty much the same old postings, frightened people relatively new to the site delineating their symptoms and asking if it sounded like AL* while old-timers comforted them and said no, it didn't, that ALS was this or that while they had classic BFS symptoms. It is repeated so often it's ritualistic. I wanted to post a comforting email about how once I had managed to control my obsession about having ALS, I got better as my body calmed down and healed.

Since then, I've looked into the statistics of ALS, which has an incidence rate of 2-5 per 100,000 in the US. That's extraordinarily low. Even though the odds are very stacked in their favor, BFS'ers might want to look the disease in the eye (as Darcy did) and just confront what may or may not happen to them and make their choices from there.

I wish that I were more involved with ALS support, like donations or walks, etc. But I admit that I'm not. I do check in from time to time with the BSF folks because I really feel like they are my peeps--American Panic at its most vulnerable and often eloquent. I always try to help them because, despite my sometimes-continued craziness, I think I'm a lot better.

Anyway, without wanting to be maudlin or exploitative of Darcy's death, I do just want to say that I still think about her even though I really only glancingly knew her back in the mid-90's. I know that I probably will not suffer from a motor neurone disease, but being sick that summer made me realize that you can or should never discount what could happen to you. We're not that special. Bad things will, eventually happen to you as they will to everyone. So keep that in mind and live your life.



Swine Flu tracker app for iPhone

This is just what I need. Not really.

Swine flu tracker app for iPhone allows you to panic anywhere.