How Does a Shotgun Pellet Migrate?

Plus, can birdshot give you lead poisoning?

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The man Dick Cheney inadvertently blasted with a shotgun suffered a minor heart attack on Tuesday morning. A pellet lodged in Harry Whittington’s torso appears to have migrated to his heart. Doctors say that Whittington may have between six and 200 pieces of birdshot lodged in his body. How does a pellet move around once it’s inside you? And can birdshot give you lead poisoning?

Gravity can move a pellet of birdshot lower in your body, at least until enough scar tissue has built up to hold it in place. If the pellet ends up in a hollow organ like the stomach, it can jostle around or make its way through your digestive tract. Bullets in the brain seem to pose an especially serious risk of further injury—people who get shot in the head have to worry about “moving bullet syndrome.”

Bullets or pellets can also move around in your bloodstream. If a pellet manages to pierce one side of a blood vessel but not the other, it might get swept into circulation. The smaller the projectile, the more likely it is to move around in the blood. Heavier bullets tend to migrate downward, while a tiny pellet might be carried along toward the heart. In 1992, the Associated Press described a man who had been shot in the left side of his face. A fragment of the bullet had lodged in his jugular vein; doctors finally removed it from one of the chambers of his heart.

Can birdshot cause lead poisoning? Yes, but it doesn’t happen very often. Birdshot is usually made of either steel or lead, but doctors routinely leave pellets (or bullets) in the body because the risks of surgery are deemed greater then the possibility of poisoning. We don’t know what kind of birdshot Cheney was using; experts quoted in the news seem to discount the dangers of lead for his victim. Still, numerous case reports and several studies have demonstrated that gunshot injury can cause lead toxicity. A recent survey of about 500 shooting victims in South Central Los Angeles found a significant and consistent increase in blood lead levels over the months following an injury.

The chance of getting lead poisoning increases with the number of bullet fragments or pellets you have lodged inside of you. A large number of very small lead pellets—perhaps like those lodged in Whittington’s head, neck, and chest—would be the most dangerous on account of their large surface area. Pellets that end up near large joints are especially problematic; the synovial fluid contained in these spaces seems to increase the rate at which lead dissolves.

The symptoms of lead poisoning might appear within a few days after someone gets shot, but they can also turn up decades later.

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Explainer thanks James Evans of the State University of New York and William Manton of University of Texas.