[ELI5] When you accidentally inhale something, like water or food, and you cough it mostly up and are fine, how does the rest get out of your lungs and how do you not get pneumonia?

Question

[ELI5] When you accidentally inhale something, like water or food, and you cough it mostly up and are fine, how does the rest get out of your lungs and how do you not get pneumonia?

In: Biology

Answer 1

So I’m a radiologist. One of the tests I do has lots of names but the most straightforward is “video swallow” which I perform with a speech pathologist.

They mix up different liquids and foods with a material called barium sulfate that shows up on X rays. You eat and drink them while I take like “video style” low dose x rays called fluoroscopy.

What we we are looking for is making sure food goes down the right pipe. Your windpipe (trachea) is in front of your food pipe (esophagus) and the windpipe has a little flap of tissue (epiglottis) that covers it when you swallow to direct food back to esophagus.

Now, sometimes your swallow muscles are paralyzed or weak. This could be from a stoke or other neurologic condition or radiation/surgery. This causes liquid or food to get under that flap and down the windpipe. Sometimes the people hack and cough (as you do when it goes down the wrong pipe) but often they may not even notice if they have a neurologic condition. This food going down the wrong pipe and beyond the vocal cords is called aspiration.

The reason I bring this up is because even when people aspirate, it’s a small fraction of what they ingest. Most still goes back. And your body does have defenses like mucous and inflammatory cells to protect your lungs. So a little tea or mashed potatoes slipping past once a year isn’t going go to do that much. However, if it’s happening with every bite or drink every meal them that DOES cause bad pneumonias.

Also, when a healthy person aspirates and hacks and coughs, you’re actually clearing out a lot of that material that went the wrong way before it’s past the cords. Maybe a drop or so falls but that causes such a reaction you protect yourself.

Note, this is a very different process to aspirated foreign bodies like pieces of a toy or hotdogs with children or when someone “can’t breath” and needs the heimlich. If you or someone you know is worried that something substantial was aspirated, seek medical attention.