Words of Wisdom

"There is no doubt that the first appearance of the mammal, with his unexplained need to push his testicles out of their proper home into the air, made a mess of the three-layered abdominal wall that had done the reptiles well for 200 million years."

-Sir William Heneage Ogilvie

A-licious

One of the liver's many functions is to store Vitamin A. There have been reports of Vitamin A intoxication after eating various livers, especially polar bear livers. When the time comes in your life that you are eating a polar bear, avoid the liver.

Scared....muscleless?

And now back, after a brief encounter with what was hopefully H1N1 (so I don't have to deal with it later) and the subsequent biochem quiz!

I present to you this fantastically funny video (don't worry, the goats aren't hurting):

http://www.youtube.com/watch?v=RGz97dxGHV8&feature=related

Myotonia is a disease that is thought to be caused by a defective ion channel in muscle. The chloride channel is responsible for allowing muscles to relax after they have been stimulated to contract. In people and animals, a defective chloride channel in skeletal muscles leads to a short delay (about 5-7 seconds, if you watch the video carefully) before the muscles can relax. This is normally only triggered when there is extreme muscle stimulation, so people learn to cope with this disease by moving slowly. Fortunately for our amusement, goats have not figured out this little trick.

Collapsed Lung- House vs. Real Life

If you have been introduced to the formulaic awesomeness that is the weird-shit solving of House MD then you have probably seen a representation of a collapsed lung, because it's basically their second favorite thing to do (right after anal bleeding). Here is a rough summary of House's version of a collapsed lung:

Patient has weird symptoms. Patient suddenly starts gasping and choking and maybe flailing. Incredibly hot doctor put a stethoscope on the chest and shouts "his lung's collapsed". Second incredibly hot doctor runs over and pokes a thin metal tube through patient's chest. One hissing sound later, and the patient is perfectly fine again and no one mentions how he's now got a metal tube through his chest.

REAL collapsed lung is much more boring. It also has a much more complicated name, pneumothorax (pneumo=air, thorax=chest). To understand pneumothorax, you have to understand how we breathe.

Our lungs are sitting in our chest cavity, which is created by our ribcage on the top and sides, and our diaphragm on the bottom. And maybe some muscles in there too, if you're not a skeleton. But just the diaphragm on the bottom. In the active portion of breathing, inhalation (inspiration), we contract muscles that pull the diaphragm downward which enlarges the chest cavity. However, there is no way for air to get into the chest cavity (important-remember this later) so this creates a negative pressure. This negative pressure basically pulls the lung tissue outward, transferring the negative pressure to the inside of the lungs. This negative pressure in the lungs causes air to rush in, just like a vacuum.

Exhaling (expiration) is the easy part- all muscles relax, the diaphragm rises to its natural position and air is pushed out.

The simplest scenario to create a collapsed lung is if there is an injury to the chest cavity (say, like, someone poked a thin metal tube through your chest. Huh.) Now what happens? The diaphragm moves downward, and the chest cavity expands, creating a negative pressure in the chest cavity. NOW however, there is a way for air to get into the cavity. So instead air rushes in to fill the chest cavity. Your lung does not get pulled open, so no air enters them, so you don't get oxygen. You breathe out and the air gets pushed back out, but when you try to breathe in the air again just fills the chest cavity and not the lungs.

The fortunate catch is that your chest cavity is actually divided, one for each lung, so lung collapses occur individually. You can still breathe with your other lung. So a collapsed lung is not in fact a medical emergency- people can go quite some time with a pneumothorax, and most small pneumothoraxes actually just fix themselves.

So does House lie?!

Only a little. What House is showing is actually a tension pneumothorax. Same deal as before, but instead of an open hole, you have a little flap that can bend into your chest but not out. When you try to breathe in, air fills your left chest cavity (because your injury is on your left cause I said so). But when you try to breathe out, the pressure holds the flap closed and no air escapes. Breathe in- a little more air in the cavity. Try to breathe out- air doesn't leave. Basically, you are blowing up your left chest cavity like a balloon. Unfortunately, there are other things in your chest, like your heart, good lung, esophagus, trachea, and other mildly important things that don't appreciate being squished. As they start being compressed, the tension pneumothorax becomes an immediate medical emergency. And this is when the thin metal tube comes in.

Basically, what House (and real doctors) are doing here is turning a tension pneumothorax into a plain old boring pneumothorax. Sure, one lung is still collapsed, but at least your heart and other lung are functioning, and breathing and beating are useful for living. The actual collapsed lung will take several days to weeks to fully re-inflate, and will probably require some suction of air out of the chest cavity.

It is good to note that normal pneumothorax should be treated as well, because it does place some strain on the heart, and this can be damaging over time.