It happened about four years ago, and the injury itself wasn't bad at all. I scratched my right calf on some brambles while clearing brush alongside a stairway in our backyard that leads to a boat dock. I didn't think much about it at the time, just wiped away the blood with my hand.
A day or two later, I had a temperature, chills, dizziness, and my wife thought I was a little confused. It was a Sunday, and she wanted me to go to a nearby doc-in-the-box; I wanted to take a few aspirins, suck it up, and then see our family practitioner the next day. That didn't happen. Within a couple of hours, my fever was sky-high, and I was shivering badly, so she took me to the ER instead. I was admitted immediately and ended up spending the next week in the hospital. It was sepsis, and they traced the original infection to the scratch on my leg. Thank goodness they caught it fairly early, and I never needed to go to the ICU.